Bioreactor Design and Optimization

In vitro modeling of brain tissue is a promising but not yet resolved problem in modern neurobiology and neuropharmacology. Complexity of the brain structure and diversity of cell-to-cell communication in (patho)physiological conditions make this task almost unachievable. However, establishment of novel in vitro brain models would ultimately lead to better understanding of development-associated or experience-driven brain plasticity, designing efficient approaches to restore aberrant brain functioning. The main goal of this review is to summarize the available data on methodological approaches that are currently in use, and to identify the most prospective trends in development of neurovascular unit, blood-brain barrier, blood-cerebrospinal fluid barrier, and neurogenic niche in vitro models. The manuscript focuses on the regulation of adult neurogenesis, cerebral microcirculation and fluids dynamics that should be reproduced in the in vitro 4D models to mimic brain development and its alterations in brain pathology. We discuss approaches that are critical for studying brain plasticity, deciphering the individual person-specific trajectory of brain development and aging, and testing new drug candidates in the in vitro models.

Micro-propagation is the primary technique for the mass propagation of greenhouse orchids. However, various factors, including culture media and cultivation systems, influence the scaling-up and efficient commercialization of in vitro techniques. The utilization of liquid cultivation systems and bioreactors are relatively cost-effective and has attracted significant attention for mass production. In this study, we evaluated the effects of eight culture media, in both semi-solid and liquid forms, on the growth of in vitro mini-plantlets of Phalaenopsis orchids. We subsequently assessed the performance of four selected media: half-strength modified Murashige and Skoog (1/2 MMS), modified FAST (MFAST), and two simplified media (SM1 and SM2), across four types of cultivation systems, including semi-solid media in glass jars, liquid media in a permanent immersion system using Erlenmeyer flasks on a shaker (PIS), and a temporary immersion system (TIS) in two forms: FA-Bio bioreactor (TIS-FA-Bio) and RITA® bioreactor (TIS-RITA®).

A demonstration Algal-Bacterial Selenium Removal (ABSR) Facility has been treating agricultural drainage water in the Panoche Drainage District on the west-side of the San Joaquin Valley since 1997. The goals of the project are to demonstrate the effectiveness of the ABSR Technology for selenium removal, to investigate potential wildlife exposure to selenium at fullscale facilities, and to develop an operational plant configuration that will minimize the life cycle cost for each pound of selenium removed. The Facility consists of a series of ponds designed to promote native microorganisms which remove nitrate and selenium. Previous treatment research efforts sought to reduce selenium concentrations to less than 51lglL, but the ABSR Facility demonstration focuses on providing affordable reduction of the selenium load that is discharged to the San Joaquin River. During 1997 and 1998, the best-performing ABSR plant configuration reduced nitrate over 95% and reduced total soluble selenium mass by 80%. Ongoing investigations at the Facility focus on optimizing operational parameters and determining operational costs and scale-up engineering requirements. The preliminary total cost estimate for a 10 acre-ftlday ABSR facility is less than $200 per acre-ft of treated drainage water. Solutions to Drainage Selenium Problem Agricultural drainage water treatment for selenium removal has been an active area of research for over a decade since the discovery of deformed waterfowl embryos at Kesterson Reservoir in the western San Joaquin Valley (Ohlendorf et ai., 1986). As yet no treatment technology has proven economically feasible for meeting the 5 Ilg/L State Water Resources Control Board objective for selenium discharged to receiving waters such as the San Joaquin River and Mud Slough (SWRCB, 1989; U.S. EPA, 1987). Agricultural drainage discharged into Mud Slough from the Grasslands Basin exceeds this concentration regularly (CVRWQCB, 1999).

Biomass accumulation and tropane alkaloids production by diploid and tetraploid hairy root cultures of Datura stramonium L. cultivated in stirred tank bioreactor at different aeration rates were investigated. The maximal growth for both hairy root cultures (ADB = 8.3 g/L and 6.8 g/L for diploid and tetraploid line, respectively) was achieved at aeration rate of 15.0 L/(L.h). The corresponding growth indexes were remarkably high (GIDW = 9.0 and 7.8 for diploid and tetraploid line, respectively) compared to the values, usually reported for other hairy root cultures. The optimal aeration rate for biomass accumulation was also optimal for alkaloids biosynthesis. According to our survey, the achieved maximal amounts of accumulated hyoscyamine (35.0 mg/L and 27.0 mg/L for diploid and tetraploid line) were the highest reported in the scientific literature for D. stramonium L. hairy roots. During the cultivation in stirred tank bioreactor, the hairy roots biosynthesized pharmaceutically important alkaloid scopolamine in minor concentrations. This is an important observation since scopolamine was not detected during submerged cultivation of these hairy root lines in other bioreactor types. However, the ploidy level was found to be the most important factor concerning scopolamine production by D. stramonium L. hairy roots cultures. The present work demonstrated the effect of ploidity levels on biomass accumulation and tropane alkaloids production by D. stramonium L. hairy roots cultivated in stirred tank bioreactor. This investigation show that the stirred tank bioreactor could be successfully applied for both maximal biomass accumulations, as well as for manipulation of tropane alkaloids production by diploid and tetraploid D. stramonium L. hairy root cultures.

The usual bacterial disease infecting mankind is urinary tract infection (UTI). Any illness that affects ureters, bladder, kidneys, or urethra is referred to UTI, where urinary bladder and urethra are highly affected. The women have been reported to be more prone to UTI, can cause discomfort and annoyance. If UTI spreads to kidneys, it may cause severe damage and dangerous repercussions. A UTI could be controlled by using different antibiotics. However, etiologists have recommended certain precautionary measures, which lower the risk of contracting a UTI in the first place. A significant component of UTI treatment consists of bactericidal antibiotics. However, self-medication and overdoses of these antibiotics given for prolonged periods may cause hamper patient's immune system and causing multiple drug resistance in the pathogenic microbes. The UTI has been reported to be caused by bacteria, fungi and some viruses (as opportunistic pathogen). The incidence of UTI prevails to higher extent in elderly women. The present study has been done extensively to study use of newer approaches in combating UTI, which may prove useful in understanding, preventing, managing, and curing this disease more effectively.

This study focuses on optimizing bioreactor design for enhanced biofuel production by integrating
Computational Fluid Dynamics (CFD), hybrid heuristic algorithms, and the Neighborhood Attraction Firefly
Algorithm (NaFA). The goal is to improve biofuel yield and process efficiency by optimizing the microalgae
cultivation environment. Using ANSYS-FLUENT software, we analyze fluid dynamics and mixing patterns
essential for efficient nutrient distribution and gas exchange. Advanced algorithms refine bioreactor
configurations, and NaFA boosts light penetration and nutrient delivery. Our approach contributes a novel
bioreactor design framework combining computational accuracy with bioengineering practices to advance
sustainable energy solutions.

The performances of radial-axial flow (Rushton-Maxflo impellers) and axialradial flow (Maxflo-Rushton impellers) mixers in the laminar-transitional flow regime were experimentally and numerically investigated with Newtonian and non-Newtonian fluids. The rheological properties for a fermentation broth consisting of the fungus Beauveria bassiana were studied under different hydrodynamic conditions in these systems. The bioreactor was a continuous stirred-tank reactor (CSTR), set at different stirring velocities. The rheology of the systems exhibited shear-thinning behavior which was modeled with the power law model. The experimental hydrodynamics and configuration modes were compared and simulated with a model fluid system and by numerical criteria (computational fluid dynamics). The R-M mode was found to be more efficient than the M-R rotating mode in terms of energy and homogenization time. The results will help in the optimization of scale-up production of these fungi.

This study specifically examines the process of producing and analyzing biodiesel made from castor oil using base-catalyzed transesterification. The catalyst used in this process is potassium hydroxide (KOH), and the methanol (CH₃OH) used has a purity of 99.9%. The biodiesel obtained was analyzed extensively to assess its quality. The characterization techniques employed were Gas Chromatography (GC) for compositional analysis, Flash Point measurement for safety assessment, Kinematic Viscosity evaluation for flow properties, and Density determination for mass-volume relationships. To perform a statistical analysis, the Response Surface Method (RSM) was employed to determine the optimal conditions that would yield the highest rate of biodiesel production among the potential solutions. This study focused on three key variables affecting the transesterification process: ultrasonic duty cycle (using a 24 kHz ultrasonic method varying the duty cycle from 20% to 100%), ultrasonic amplitude (varying from 20% to 100%), and reaction time (spanning from 10 to 15 minutes). This investigation achieved a biodiesel yield of 88.38% using a 60% ultrasonic amplitude, a single ultrasonic cycle, and a 15-minute reaction time. The regression model developed can be used to predict biodiesel's percentage conversion.

We greatly appreciate the time and effort the Reviewers and Editor have put into evaluating and improving our manuscript. We have copied the Reviewers' questions and comments below and followed them with our responses. Editor's comments: In addition to the changes requested by the referees, I would like you to consider whether figures 1 and 3 are really necessary. I like to keep papers concise and I cannot see that these figures add anything to the understanding of the text. According to the Editor's suggestion, Figures 1 and 3 have been eliminated. Reviewer #1: General comments. Methods. How was the degree of staining of the histological specimens quantified for the purpose of scoring (page 4), or was this done subjectively? The degree of staining was evaluated subjectively by Donald Salter, Professor of Osteoarticular Pathology at the University of Edinburgh, UK. This has been clarified in the revised text (Page 4, 2 nd paragraph) The measurement and calculation of tensile modulus could be more clearly explained, in particular the dimensions that were recorded during each test (with reference to Fig. 1b, or diagram) and how the measurements at each strain were processed to obtain the data presented in Fig. 6. Also, why were the same tests not performed on native meniscus for direct comparison? Data presented in Fig. 6 were obtained using standard calculations to derive the elastic modulus of materials based on stress-strain curves. In order to better characterize the dimensions recorded, the description has been revised as follows:"Changes in dimensions during loading were obtained with a digital image analysis system (Adapted QuickCam® Pro 3000, Logitech Europe S.A., Switzerland and the GNU Image Manipulation Program, www.gimp.org), and were always lower than 10% of the gauge length considered." (Methods, page 6, 1 st paragraph). The same tensile tests could not be performed on the inner or outer regions of native meniscus: in fact, out of those regions, having a semilunar shape, it would not be possible to punch ring-shaped specimens. This is now discussed in the following sentence: "Since mechanical tests used in this work are not standard and require specimens of specific geometries, a comparison of the compressive and tensile properties of the engineered constructs with those of the native meniscus could not be established or derived from data in the literature,, (Discussion, Page 10, 1 st paragraph) Discussion. The authors state that the mechanical properties of the HYAFF scaffold were negligible. Nevertheless, the scaffold must surely influence tissue formation: to what extent does the presence of the scaffold contribute (directly or indirectly) to the differences between the inner and outer regions reported here? We now clarify that "Since the mechanical properties of the non-woven mesh scaffold used are negligible, the mechanical functionality of the bi-zonal engineered constructs was mainly due to the differential deposition of extracellular matrix by chondrocytes." (Discussion, page 9, last paragraph) and discuss that "The HYAFF ®-11 non-woven meshes used in this study were supportive of the formation of bi-zonal tissues. The composition and open structure of the meshes may have contributed respectively to the deposition of GAG in the inner region and to the outgrowth of cells towards the outer capsule. " (Discussion, page 8, last paragraph) To what extent might these differences also be accounted for by the increase in cell number and viability when cultured under dynamic as opposed to static conditions? Likewise, is the preferential orientation of the collagen fibers not due simply to the increased rate of growth of the fibrous capsule when cultured under conditions of improved mass transport rather than hydrodynamic shear per se (N.B. the RCCS is considered a low shear environment)? We now describe that "In the outer capsule, cells were elongated and at a higher density than in the central region" (Results, Page 6, last paragraph) and discuss that "More fundamental studies would be required to determine the role of increased mass transport and/or increased cell density following application of hydrodynamic flow in the development of the bi-zonal tissues." (Page 9, 1 st paragraph) Response letter Introduction, page 1, third paragraph: reference # 16. Authors should not self-cite with manuscripts which were only submitted, without being accepted. Reference 16 is now In Press. The reference list has been updated Materials and methods, page 2 first paragraph: 0.15% type II collagenase does not clearly indicate the amount of enzyme used. An indication of the Units would be more accurate. In fact, 22 hours of digestion seems to be a long time, with respect to the overnight digestion of the common protocols. An indication of the vitality of the cells after the enzymatic isolation should also be indicated. We now detail that the activity of the enzymes used was varying between 180 to 250U/mg and that cell viability after digestion was greater than 80% (Methods, page 2, last paragraph) Results, page 6, second paragraph, second line: typo in "characterization".

The intent of the proposed system was to develop an insitu biotreatment system for swine manure that should involve minimum handling by the farmer. A demonstration plant has been installed in the Paris region. The intensive lagooning system consists of algal ponds, daphnid ponds and a polishing fish pond working in series with a total area of 2100 m 2 and a total volume of 3600 m ~. The performance of the system was evaluated under winter conditions with raw decanted swine manure by measuring N-NH; and P-PO~-removal, pH, temperature, water oxygen, algal biomass and daphnid productions. Results showed that low temperatures (< 5°C) did not allow any significant biomass production (0.41-t~68 g dry mass~m-' d). Ammonia-nitrogen, mostly stripped (98% lost by stripping), and phosphate removals were small. However, as soon as the temperature increased in spring (March), ammonia-nitrogen removal was improved with a large contribution (71%) due to stripping and the algal productivity increased to-~ 3"5 g dry mass/m e d; CO: appeared to be a limiting factor. Ammonia-nitrogen, nitrate, nitrite and orthophosphate showed marked variations that could be correlated with manure overdoses.

Photon arrival time statistics significantly affect the performance of the photosynthetic system under a pulsedlight regime when the average number of photons hitting the Chlorophyll antenna of PS II is small. As a result, the interpretation of measurements of the production rate of biomass or other products of unicellular algae under a pulsed-light regime and the comparison of the results with those obtained under continuous illumination depends crucially upon accounting for these statistics.

␣-Chymotrypsin encapsulated in reversed micelles formulated with dioleyl phosphoric acid has been used as a nanostructural bioreactor for the hydrolysis of amino acid derivatives in aqueous media. The enzymatic activity entrapped in the reversed micelles remained at more than 90% activity for the successive one month owing to an insulating environment for the enzyme.

A detailed review was conducted to explore waste cooking oil (WCO) as feedstock for biodiesel. The manuscript highlights the impact on health while using used cooking oil and the scope for revenue generation from WCO. Up to a 20% blend with diesel results in less pollutants, and it does not demand more modifications to the engine. Also, this reduces the country’s import bill. Furthermore, it suggests the scope for alternate sustainable income among rural farmers through a circular economy. Various collection strategies are discussed, a SWOC (strength, weakness, opportunity, and challenges) analysis is presented to aid in understanding different countries’ policies regarding the collection of WCO, and a more suitable method for conversion is pronounced. A techno-economic analysis is presented to explore the viability of producing 1 litre of biodiesel. The cost of 1 litre of WCO-based biodiesel is compared with costs Iran and Pakistan, and it is noticed that the difference among them is less than 1%. Life cycle assessment (LCA) is mandatory to reveal the impact of WCO biodiesel on socio-economic and environmental concerns. Including exergy analysis will provide comprehensive information about the production and justification of WCO as a biodiesel.
Keywords: waste cooking oil; biodiesel; circular economy; economic analysis

Tissue engineered heart valves (TEHV) have been observed to respond to mechanical conditioning in vitro by expression of activated myofibroblast phenotypes followed by improvements in tissue maturation. In separate studies, cyclic flexure, stretch, and flow (FSF) have been demonstrated to exhibit both independent and coupled stimulatory effects. Synthesis of these observations into a rational framework for TEHV mechanical conditioning has been limited, however, due to the functional complexity of trileaflet valves and the inherent differences of separate bioreactor systems. Toward quantifying the effects of individual mechanical stimuli similar to those that occur during normal valve function, a novel bioreactor was developed in which FSF mechanical stimuli can be applied to engineered heart valve tissues independently or in combination. The FSF bioreactor consists of two identically equipped chambers, each having the capacity to hold up to 12 rectangular tissue specimens (25 × 7.5 × 1 mm) via a novel "spiralbound" technique. Specimens can be subjected to changes-in-curvature up to 50 mm −1 and uniaxial tensile strains up to 75%. Steady laminar flow can be applied by a magnetically coupled paddlewheel system. Computational fluid dynamic (CFD) simulations were conducted and experimentally validated by particle image velocimetry (PIV). Tissue specimen wall shear stress profiles were predicted as a function of paddlewheel speed, culture medium viscosity, and the quasi-static state of specimen deformation (i.e., either undeformed or completely flexed). Velocity profiles predicted by 2D CFD simulations of the paddlewheel mechanism compared well with PIV measurements, and were used to determine boundary conditions in localized 3D simulations. For undeformed specimens, predicted inter-specimen variations in wall shear stress were on average ±7%, with an average wall shear stress of 1.145 dyne/cm 2 predicted at a paddlewheel speed of 2000 rpm and standard culture conditions. In contrast, while the average wall shear stress predicted for specimens in the quasi-static flexed state was ~59% higher (1.821 dyne/cm 2), flexed specimens exhibited a broad intra-specimen wall shear stress distribution between the convex and concave sides that correlated with specimen curvature, with peak wall shear stresses of ~10 dyne/ cm 2. This result suggests that by utilizing simple flexed geometric configurations, the present system can also be used to study the effects of spatially varying shear stresses. We conclude that the present design provides a robust tool for the study of mechanical stimuli on in vitro engineered heart valve tissue formation.

Gas holdup and liquid circulation velocity were studied in a two-dimensional air lift reactor. A comparison was made between bubble column and air lift operation. Four different gas spargers were studied, and several different gases: He, CO,, Ar. air and Freon 114. No influence on the measured variables could be attributed to gas distribution. The nature of the gas had a strong influence in the case of bubble column operation. Helium does not exhibit the maximum in the holdup which is characteristic of the "transition regime", and in general gives lower values. In air lift operation, the differences due to the nature of the gases are much smaller, and can be neglected. The liquid recirculation velocity depends on the gas superficial velocity, J,, raised to the power 0.4. This concurs with published data obtained in large air lift devices. It is concluded that a two-dimensional air lift can be used for research and development, since it presents the same basic fluiddynamic characteristics as large air lift reactors. In addition, the two-dimensional device allows the examination of flow patterns and configuration, which are decisive in design and scale-up of this type of reactor.

Lee (Republic of Korea); P. Adlercreutz (Sweden); 0. Yenigun (Turkey); P. N. Campbell (UK). ?The Commission has chosen this series with a view to intensify the interrelations of chemistry and biotechnology. By improving the knowledge of chemists in the field of biotechnology it is hoped to initiate more ideas for applying biological methods in chemistry, inspire more use of chemical knowledge in the biological sciences and help scientists in both fields to work closer together. In the articles in the series, to be published in this journal, outstanding experts in their respective fields will give (a) an overview on topics related to the practical use of biotechnological methods in organic chemistry, (b) an outlook on upcoming research topics, their impact on existing areas and their potential for future developments. The Commission solicits comments as well as suggestions for future topics, and will aim to help in providing answers to any questions in this field. Names of countries given after Members' names are in accordance with the ZUPAC Handbook 1991-93; changes will be effected in the 1994-95 edition. Republication of this report is permitted without the need for formal IUPAC permission on condition that an acknowledgement, with full reference together with IUPAC copyright symbol (0 1994 IUPAC), is printed. Publication of a translation into another language is subject to the additional condition of prior approval from the relevant IUPAC National Adhering Organization.

The chalcogens selenium (Se) and tellurium (Te) are rare earth elements, which are mainly present in the environment as toxic oxyanions, due to the anthropogenic activities. Thus, the increased presence of these chalcogen-species in the environment and the contamination of wastewaters nearby processing facilities led to the necessity in developing remediation strategies aimed to detoxify waters, soils and sediments. Among the different decontamination approaches, those based on the ability of microorganisms to bioaccumulate, biomethylate or bioconvert Se-and/or Te-oxyanions are considered the leading strategy for achieving a safe and eco-friendly bioremediation of polluted sites. Recently, several technologies based on the use of bacterial pure cultures, bacterial biofilms or microbial consortia grown in reactors with different configurations have been explored for Se-and Te-decontamination purposes. Further, the majority of microorganisms able to process chalcogen-oxyanions have been described to generate valuable Se-and/or Te-nanomaterials as end-products of their bioconversion, whose potential applications in biomedicine, optoelectronics and environmental engineering are still under investigation. Here, the occurrence, the use and the toxicity of Se-and Te-compounds will be briefly overviewed, while the microbial mechanisms of chalcogen-oxyanions bioprocessing, as well as the microbialbased strategies used for bioremediation approaches will be extensively described.

The thermophilic anaerobic metal-reducing bacterium Thermoanaerobacter sp. X513 efficiently produces zinc sulfide (ZnS) nanoparticles (NPs) in laboratory-scale (≤ 24-L) reactors. To determine whether this process can be up-scaled and adapted for pilot-plant production while maintaining NP yield and quality, a series of pilot-plant scale experiments were performed using 100-L and 900-L reactors. Pasteurization and N2-sparging replaced autoclaving and boiling for deoxygenating media in the transition from small-scale to pilot plant reactors. Consecutive 100-L batches using new or recycled media produced ZnS NPs with highly reproducible ~2-nm average crystallite size (ACS) and yields of ~0.5 g L(-1), similar to the small-scale batches. The 900-L pilot plant reactor produced ~320 g ZnS without process optimization or replacement of used medium; this quantity would be sufficient to form a ZnS thin film with ~120 nm thickness over 0.5 m width × 13 km length. At all scales, the bacteria pr...

We greatly appreciate the time and effort the Reviewers and Editor have put into evaluating and improving our manuscript. We have copied the Reviewers' questions and comments below and followed them with our responses. Editor's comments: In addition to the changes requested by the referees, I would like you to consider whether figures 1 and 3 are really necessary. I like to keep papers concise and I cannot see that these figures add anything to the understanding of the text. According to the Editor's suggestion, Figures 1 and 3 have been eliminated. Reviewer #1: General comments. Methods. How was the degree of staining of the histological specimens quantified for the purpose of scoring (page 4), or was this done subjectively? The degree of staining was evaluated subjectively by Donald Salter, Professor of Osteoarticular Pathology at the University of Edinburgh, UK. This has been clarified in the revised text (Page 4, 2 nd paragraph) The measurement and calculation of tensile modulus could be more clearly explained, in particular the dimensions that were recorded during each test (with reference to Fig. 1b, or diagram) and how the measurements at each strain were processed to obtain the data presented in Fig. 6. Also, why were the same tests not performed on native meniscus for direct comparison? Data presented in Fig. 6 were obtained using standard calculations to derive the elastic modulus of materials based on stress-strain curves. In order to better characterize the dimensions recorded, the description has been revised as follows:"Changes in dimensions during loading were obtained with a digital image analysis system (Adapted QuickCam® Pro 3000, Logitech Europe S.A., Switzerland and the GNU Image Manipulation Program, www.gimp.org), and were always lower than 10% of the gauge length considered." (Methods, page 6, 1 st paragraph). The same tensile tests could not be performed on the inner or outer regions of native meniscus: in fact, out of those regions, having a semilunar shape, it would not be possible to punch ring-shaped specimens. This is now discussed in the following sentence: "Since mechanical tests used in this work are not standard and require specimens of specific geometries, a comparison of the compressive and tensile properties of the engineered constructs with those of the native meniscus could not be established or derived from data in the literature,, (Discussion, Page 10, 1 st paragraph) Discussion. The authors state that the mechanical properties of the HYAFF scaffold were negligible. Nevertheless, the scaffold must surely influence tissue formation: to what extent does the presence of the scaffold contribute (directly or indirectly) to the differences between the inner and outer regions reported here? We now clarify that "Since the mechanical properties of the non-woven mesh scaffold used are negligible, the mechanical functionality of the bi-zonal engineered constructs was mainly due to the differential deposition of extracellular matrix by chondrocytes." (Discussion, page 9, last paragraph) and discuss that "The HYAFF ®-11 non-woven meshes used in this study were supportive of the formation of bi-zonal tissues. The composition and open structure of the meshes may have contributed respectively to the deposition of GAG in the inner region and to the outgrowth of cells towards the outer capsule. " (Discussion, page 8, last paragraph) To what extent might these differences also be accounted for by the increase in cell number and viability when cultured under dynamic as opposed to static conditions? Likewise, is the preferential orientation of the collagen fibers not due simply to the increased rate of growth of the fibrous capsule when cultured under conditions of improved mass transport rather than hydrodynamic shear per se (N.B. the RCCS is considered a low shear environment)? We now describe that "In the outer capsule, cells were elongated and at a higher density than in the central region" (Results, Page 6, last paragraph) and discuss that "More fundamental studies would be required to determine the role of increased mass transport and/or increased cell density following application of hydrodynamic flow in the development of the bi-zonal tissues." (Page 9, 1 st paragraph) Response letter Introduction, page 1, third paragraph: reference # 16. Authors should not self-cite with manuscripts which were only submitted, without being accepted. Reference 16 is now In Press. The reference list has been updated Materials and methods, page 2 first paragraph: 0.15% type II collagenase does not clearly indicate the amount of enzyme used. An indication of the Units would be more accurate. In fact, 22 hours of digestion seems to be a long time, with respect to the overnight digestion of the common protocols. An indication of the vitality of the cells after the enzymatic isolation should also be indicated. We now detail that the activity of the enzymes used was varying between 180 to 250U/mg and that cell viability after digestion was greater than 80% (Methods, page 2, last paragraph) Results, page 6, second paragraph, second line: typo in "characterization".

The last few decades have seen an overwhelming increase in the amount of research carried out on the use of inorganic nanoparticles. More fascinating is the tremendous progress made in the use of chalcogen and chalcogenide nanoparticles in cancer theranostics. These nanomaterials, which were initially synthesized through chemical methods, have now been efficiently produced using different plant materials. The paradigm shift towards the biogenic route of nanoparticle synthesis stems from its superior advantages of biosafety, eco-friendliness, and simplicity, among others. Despite a large number of reviews available on inorganic nanoparticle synthesis through green chemistry, there is currently a dearth of information on the green synthesis of chalcogens and chalcogenides for cancer research. Nanoformulations involving chalcogens such as sulfur, selenium, and tellurium and their respective chalcogenides have recently emerged as promising tools in cancer therapeutics and diagnosis. Sim...

Purpose Selenium (Se) toxicity or deficiency disorders are chiefly associated with Se concentration and speciation in soils. Elevated soil Se content may lead to contamination of water bodies and groundwaters due to the leaching caused by rainfall and irrigation. This study is focused on Se removal by in situ (biostimulation and bioaugmentation) and ex situ (soil washing) bioremediation as well as on its recovery. Materials and methods In this research, in situ bioremediation of Se-rich soil collected from rice fields in Ludhiana, Northwest India was studied in microcosms. The effect of biostimulation was determined by amending soil with different organic sources (fermentable, non-fermentable, and non-hydrolysable electron donors). The effect of bioaugmentation was determined by adding anaerobic granular sludge to the microcosms. With regard to ex situ bioremediation, the Se-rich soil was leached with water and the resulting leachate was biologically treated in an upflow anaerobic sludge blanket (UASB) reactor using lactate as electron donor. The UASB reactor was operated for 78 days in different conditions of lactate (electron donor) dosing to achieve maximum Se removal and recovery as elemental Se(0) on the granular sludge. The effluent of the UASB reactor was regularly analyzed to determine Se removal efficiencies. Results and discussion The effect of biostimulation and bioaugmentation showed no significant difference in terms of Se reduction profiles in the microcosms. This suggested that the indigenous Se-reducing microorganisms and oxidizable organic carbon present in the soil are sufficient for in situ soil bioremediation. During treatment of soil leachate in the UASB reactor, 90% Se removal was achieved irrespective of the lactate dosing and mineral salt medium composition of the reactor influent. Analysis of the granular sludge using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) and powder X-ray diffraction (P-XRD) confirmed the presence of elemental Se on the granular sludge. The total Se concentration in the anaerobic granular sludge amounted to 43.5 (± 0.7) μg Se per gram of granular sludge. Conclusions In situ bioremediation achieved Se reduction in the Se-rich soil investigated. However, risk of Se re-oxidation and leaching into groundwater after in situ remediation cannot be disregarded. In contrast, during ex situ treatment, effluent from the UASB reactor contained less than the USEPA guideline value 5 μg L −1 Se. This study showed biological treatment of Se-rich soils is suitable for cleaning the soil, Se recovery, and environmentally acceptable effluent discharge of the soil washing leachate treatment.

Aerobic methane-oxidizing bacteria are ubiquitous in the environment. Two well-characterized strains, Mc . capsulatus (Bath) and Methylosinus trichosporium OB3b, representing gamma- and alphaproteobacterial methanotrophs, respectively, can convert selenite, an environmental pollutant, to volatile selenium compounds and selenium-containing particulates. Both conversions can be harnessed for the bioremediation of selenium pollution using biological or fossil methane as the feedstock, and these organisms could be used to produce selenium-containing particles for food and biotechnological applications. Using an extensive suite of techniques, we identified precursors of selenium nanoparticle formation and also found that these nanoparticles are made up of eight-membered mixed selenium and sulfur rings.

Solid-state fermentation could be used to produce low-cost pectinases that could then be used to saccharify pectin in citrus waste biorefineries. Recently, we produced pectinases in a pilot-scale packed-bed bioreactor, growing Aspergillus niger on a substrate mixture consisting of 27 kg of wheat bran and 3 kg of sugarcane bagasse (dry mass). However, the agglomeration of particles and shrinkage of the bed created preferential flow paths, leading to overheating within the bed and poor uniformity of pectinase levels at the end of the fermentation. In the current work, we used intermittent agitation as a strategy to minimize agglomeration, comparing one agitation (10 h), three agitations (at 8, 10 and 12 h) and five agitations (every 2 h from 8 to 16 h). The pectinase activity in the bed was uniform after agitation, but poor uniformity occurred when the bed was left unmixed for more than 10 h. The best regime was that with three agitations: For 15 samples removed from different vertical and horizontal positions of the bed at 20 h, the average pectinase activity was 22 U g −1 , with a sample standard deviation of 2 U g −1. We conclude that the use of intermittently-mixed packed-bed bioreactors is a promising strategy for producing pectinases in solid-state fermentation.

In this work, valorisation of high acid value waste cooking oil (WCO) into biodiesel has been assessed using supercritical methanolysis. The effect of the water content in the feedstock has been critically investigated. Using supercritical methanolysis, the higher water content in the feedstock enhanced the hydrolysis of triglycerides to free fatty acids (FFAs) and the esterification of FFAs into fatty acid methyl esters (FAMEs) has been reported. The effect of water content has been investigated by adding different volumes of water to the feedstock prior to the reaction. Response Surface Methodology (RSM) using Central Composite Design (CCD) has been used to design the experiments and to optimise the experimental variables. Five controllable reaction parameters have been studied including methanol to oil (M:O) molar ratio, reaction temperature, reaction pressure, reaction time and water content. Biodiesel yield has been chosen as reaction response for the experimental runs. The linear effect of reaction parameters and their interactions on biodiesel yield has been analysed. It has been observed that increasing the water content of the feedstock decreases the yield of biodiesel at specific conditions. However, due to the high interactive effect between water content and reaction time, it has been observed increasing effect at longer reaction time. A quadratic model has been developed using the reported experimental results representing biodiesel yield function in all of the experimental parameters. The adequacy of the predicted model has been checked statistically using analysis of variance (ANOVA). Numerical optimisation has been applied to identify the optimal reaction conditions for maximum production of biodiesel. The developed optimal condition has reported 99.8% biodiesel yield at 10:1 M:O molar ratio, 245 o C, 125 bar, 6 vol% of water content within 19 min.

Transient and continuous recombinant protein expression by HEK cells was evaluated in a perfused monolithic bioreactor. Highly porous synthetic cryogel scaffolds (10ml bed volume) were characterised by scanning electron microscopy and tested as cell substrates. Efficient seeding was achieved (94% inoculum retained, with 91-95% viability). Metabolite monitoring indicated continuous cell growth, and endpoint cell density was estimated by genomic DNA quantification to be 5.2x10 8 , 1.1x10 9 and 3.5x10 10 at day 10, 14 and 18. Culture of stably transfected cells allowed continuous production of the Drosophila cytokine Spätzle by the bioreactor at the same rate as in monolayer culture (total 1.2 mg at d18) and this protein was active. In transient transfection experiments more protein was produced per cell compared with monolayer culture. Confocal microscopy confirmed homogenous GFP expression after transient transfection within the bioreactor. Monolithic bioreactors are thus shown to be a flexible and powerful tool for manufacturing recombinant proteins.

Cell‐based therapeutics, such as in vitro manufactured red blood cells (mRBCs), are different to traditional biopharmaceutical products (the final product being the cells themselves as opposed to biological molecules such as proteins) and that presents a challenge of developing new robust and economically feasible manufacturing processes, especially for sample purification. Current purification technologies have limited throughput, rely on expensive fluorescent or magnetic immunolabeling with a significant (up to 70%) cell loss and quality impairment. To address this challenge, previously characterized mechanical properties of umbilical cord blood CD34+ cells undergoing in vitro erythropoiesis were used to develop an mRBC purification strategy. The approach consists of two main stages: (a) a microfluidic separation using inertial focusing for deformability‐based sorting of enucleated cells (mRBC) from nuclei and nucleated cells resulting in 70% purity and (b) membrane filtration to ...

The performances of radial-axial flow (Rushton-Maxflo impellers) and axialradial flow (Maxflo-Rushton impellers) mixers in the laminar-transitional flow regime were experimentally and numerically investigated with Newtonian and non-Newtonian fluids. The rheological properties for a fermentation broth consisting of the fungus Beauveria bassiana were studied under different hydrodynamic conditions in these systems. The bioreactor was a continuous stirred-tank reactor (CSTR), set at different stirring velocities. The rheology of the systems exhibited shear-thinning behavior which was modeled with the power law model. The experimental hydrodynamics and configuration modes were compared and simulated with a model fluid system and by numerical criteria (computational fluid dynamics). The R-M mode was found to be more efficient than the M-R rotating mode in terms of energy and homogenization time. The results will help in the optimization of scale-up production of these fungi.

The project examined the optimization, design, and automation of small-scale production of biodiesel from waste cooking oil (WCO). It covered optimization proceedings (feedstock pretreatment and conditioning) that were aimed at ensuring maximum biodiesel yield from the WCO with fewer non-desired by-products such as glycerin through the esterification reaction reactions using sulphuric acid. It is noteworthy that the design generated can be used on different feedstocks. (With high Free Fatty Acids [FFA] and those without FFA). Pretreatment can be run concurrently with the Alkali catalyzed process or the processes independently of each other. Being a small-scale production, some recovery units such as the catalyst recovery unit were not employed given the economic infeasibility. The main transesterification reaction under implementation was the alkali-catalyzed process owing to its easily attainable reaction conditions and reaction time in contrast with the supercritical method and acid-catalyzed method whose major downfalls are extreme reaction conditions and longer reaction times respectively. The use of simulation program DWSIM version 8.3.5 (Classic UI, 64-bits) was employed to develop the process plant's design. The simulation was carried out at different FFA levels using a similar model developed in all cases. The data generated from the simulation was analyzed using MATLAB version R2022b and graphs describing relationships were generated. Finally, the automation of the process with aid of valves, a heater and heat exchangers.

Fermentation media consist of a large number of chemicals whose composition undergoes alteration during the course of fermentation. As a result of this, conventional methods and correlations for oxygen solubility measurement and prediction do not apply in these systems. Using a physical method, oxygen solubilities were measured in simulated chemical systems and in fermentation broths. Sugars, salts, and fermentation products were identified as major factors influencing oxygen solubility. Salt effect was correlated with electrical conductivity of the medium, which was easy to measure during fermentation. For mixtures and for fermentation medium, individual influences were found to be log-additive in accordance with Danckwerts (1970).

Souring in oil fields occurs mainly due to the activity of sulfate reducing bacteria (SRB). Most of the studies on SRB are performed using upflow packed-bed reactors that have a limitation to describe the region close to the injection wells in oil fields, which is characterized by void and saturated porous bed regions. Here, it is described the design and operation of a pilot scale system to investigate the SRB activity, inhibition and control in oil fields. The bioreactor is composed by two-compartments (empty and packed-bed). The reactor system has two parallel bioreactors that can be supplied with the same source of nutrients through a single pump or can be supplied separately with different solutions using two pumps. The hydrodynamics for conventional packed bed bioreactors has a mixing behavior dependent of the flow rate and has a significant bypass. In contrast, the two-compartment system presented here has a mixing behavior almost independent of the flow rate.

A novel method for treating sulfide-containing wastewater is described which involves treating sulfide-laden biogas produced in a bioreactor in a sulfide oxidizing unit (SOU). Oxidation in the SOU is monitored by an oxidation reduction potential (ORP) probe which minimizes the input of air/ oxygen to produce elemental sulfur without significant pro-US 8,366,932 B 1 1 MICRO-AERATION OF SULFIDE REMOVAL FROMBIOGAS CROSS-REFERENCE TO RELATED APPLICATIONS 2 hydrogen sulfide in off-gas, if sulfides in liquid are released to receiving steams, they are toxic to aquatic life and deplete oxygen concentration. This application claims priority under 35 U.S.C. § 119 of a provisional application Ser. No. 61/103,775 filed Oct. 8, 2008, which application is hereby incorporated by reference in its entirety. GRANT REFERENCE CLAUSE This invention was funded at least in part by the USDA Contract No. 2002-34188-1203 5. The government may have certain rights in this invention.

To further understand fermentation kinetics of sodium gluconate (SG) production by Aspergillus niger with different inlet oxygen concentrations, logistic model for cell growth and two-step models for SG production and glucose consumption were established. The results demonstrated that the maximum specific growth rate (µ) presented exponential relationship with inlet oxygen concentration and the maximum biomass (X) exhibited linear increase. In terms of SG production, two-step model with Luedeking-Piret equation during growth phase and oxygen-dependent equation during stationary phase could well fit the experimental data. Notably, high inlet oxygen concentration exponentially improved SG yield (Y), whereas biomass yield to glucose (Y) and cell maintenance coefficient (m) were almost independent on inlet oxygen concentration, indicating that high oxygen supply enhancing SG synthesis not only functioning as a substrate directly, but also regulating glucose metabolism towards SG formati...

Regenerative medicine has an exciting role in the treatment of disorders and conditions where there is an irreversible damage to a tissue or an organ or in immunodeficient state. Stem cells which have the potential to differentiate into specific types of cells, offers a new concept of regenerative medicine to treat spectrum of diseases including infections. Infections are one of the cause of high morbidity during injuries and in immunodeficient states. Induced pluripotent stem cells (iPSCs) are generated by genetically reprogramming the adult cells to an embryonic stem cell (ESC)-like state by being forced to express genes and factors essential for maintaining the defining properties of ESC. In infections, eosinophils play an important role as they are potent source of cytotoxic mediators such as eosinophil cationic protein (ECP) and major basic proteins (MBP). These substances play an important role in immune response to infections caused by bacteria, viruses, parasites and in resi...

This paper investigates the way modelling mixing phenomena occur in unsteady stirring conditions in agitated vessels. In particular, a new model of torus reactor including a well-mixed zone and a transport zone is proposed. The originality of the arrangement of ideal reactors developed here lies in the time-dependent location of the boundaries between the two zones. This concept is applied to model the positive influence of unsteady stirring conditions on homogenization process: the model avoids a mass balance discontinuity when the transition from steady to unsteady stirring conditions is performed. To ascertain the reliability of the model proposed, experimental runs with highly viscous fluids have been carried out in an agitated tank. The impeller used was a non-standard helical ribbon impeller, fitted with an anchor at the bottom. The degree of homogeneity in the tank was observed using a conductivity method after a tracer injection. It is shown that for a given agitated fluid and mixing system, model parameters are easy to estimate and that modelling results are in close agreement with experimental ones. Moreover, it would appear that this model allows the easy derivation of a control law, which is a great advantage when optimizing the dynamics of a mixing process.

Biodiesel is a potential renewable energy that can reduce greenhouse gas (GHG) emissions and increase energy security. Biodiesel has been shown to have lower carbon emissions compared to petroleum diesel, and it can reduce GHG by as much as 86%. Governments around the world have set targets for renewable energy, with a specific focus on the use of biofuels like biodiesel. Biodiesel can be derived from various feedstocks such as animal lipids, vegetable oils, and waste oils. It can be made through the transesterification of triglyceride with ethanol or methanol. This reaction requires strong base catalysts, such as sodium hydroxide or potassium hydroxide, in order to produce methyl esters. The potential of biodiesel has led to advancements in its production, such as the use of enzymatic transesterification, novel feedstocks, and the optimization of production parameters. Additionally, various companies have ventured into biodiesel production with a range of business models and approaches.

Two pilot-scale open raceway pond systems were designed and fabricated in the University of the Philippines Los Baños (UPLB) for the cultivation of Chlorella vulgaris Beijerinck to observe the biomass productivity of the alga in an open condition in the Philippines. One design was an oval track with a middle island, while the other was a multi-stage raceway pond (MSRP) consisted of several sections separated by baffles. The pond designs aimed to accommodate 1,000 L of culture. The nutrient media used was composed of urea, NPK (16-20-0), FeCl3, and Na2EDTA – a locally formulated medium that sustains the growth of the species. Paddlewheel was installed to provide mixing, which was turned on during the daytime, while aeration was continuously supplied through perforated air-distributor PVC pipes installed on the pond floor. Only natural light was utilized, and no lighting was provided during the night. The growth rate was generated by monitoring the biomass concentration in the pond th...

Upflow two-compartment packingfree/packed-bed bioreactors have been used in petroleum microbiology due to their similarity with the oil field close to the injection or production wells. This two-compartment configuration gives a particular hydrodynamics to the liquid phase. In this study the hydrodynamics of a pilot reactor filled with glass beads was studied using tracer experiments. The residence time distribution was calculated and interpreted. The results for interstitial Reynolds number (ReLi &lt;0.3) show curves with a peak at the beginning and a long tail that is distorted by the solution flow rate. A model composed of a continuous stirred tank, plug flow and cross-flow reactors was used to describe the flow patterns.

Regenerative medicine has an exciting role in the treatment of disorders and conditions where there is an irreversible damage to a tissue or an organ or in immunodeficient state. Stem cells which have the potential to differentiate into specific types of cells, offers a new concept of regenerative medicine to treat spectrum of diseases including infections. Infections are one of the cause of high morbidity during injuries and in immunodeficient states. Induced pluripotent stem cells (iPSCs) are generated by genetically reprogramming the adult cells to an embryonic stem cell (ESC)-like state by being forced to express genes and factors essential for maintaining the defining properties of ESC. In infections, eosinophils play an important role as they are potent source of cytotoxic mediators such as eosinophil cationic protein (ECP) and major basic proteins (MBP). These substances play an important role in immune response to infections caused by bacteria, viruses, parasites and in resi...

Regenerative medicine has an exciting role in the treatment of disorders and conditions where there is an irreversible damage to a tissue or an organ or in immunodeficient state. Stem cells which have the potential to differentiate into specific types of cells, offers a new concept of regenerative medicine to treat spectrum of diseases including infections. Infections are one of the cause of high morbidity during injuries and in immunodeficient states. Induced pluripotent stem cells (iPSCs) are generated by genetically reprogramming the adult cells to an embryonic stem cell (ESC)-like state by being forced to express genes and factors essential for maintaining the defining properties of ESC. In infections, eosinophils play an important role as they are potent source of cytotoxic mediators such as eosinophil cationic protein (ECP) and major basic proteins (MBP). These substances play an important role in immune response to infections caused by bacteria, viruses, parasites and in resi...

Achieving a resource-protecting and environment friendly provide chain whereas following economic development has consistently been the target of countries across the world. Bleaching of soybean, canola, olive, sunflower and palm oils by ultrasonic horn reactor as a green process was simulated by computational fluid dynamics (CFD) to determine the effect of viscosity, amplitude (180 and 360 W), frequency (25 and 40 kHz) and temperature (35 and 65 °C). Multiphase, unsteady and axisymmetric modeling of the process examined led to the determination of shear rates. In addition, the viscosity power law model was applied to predict the vegetable oils' viscosity with high accuracy. Besides that, the fatty acid composition of vegetable oils was measured by gas chromatography. ΣPUFA/(ΣMUFA + ΣSFA) content was highest for soybean (1.39) and lowest for palm oil (0.07). A positive relation was found between the color of bleached oil and ultrasound frequency and viscosity. It was found that the flow shear rate reduced with increasing the temperature and power of sonication. The creation of regions with a high velocity gradient and, consequently, elevated shear rates (especially near the horn tips or at the corners) affected oil viscosity. Sunflower oil behaved as a shear thinning fluid, except at moderate shear rates where Newtonian properties were observed. Rheological characteristics of palm oil were similar to those of olive oil as a shear thinning fluid. Semi-empirical correlations are proposed to determine the viscosity of oil as a function of its shear rate for this green process.

Spirulina is blue-green microalgae grows abundantly on organic matters rich water bodies. In normal condition the algae uses up the organic matters effectively and improves the quality of water through decreasing of biochemical oxygen demand (BOD5) and chemical oxygen demand (COD); while in overpopulated condition the algae may worsens water quality. This characteristic has shown that the algae can be used to improve water quality up to certain population density. However, until now this algae has not been used to improve the quality of liquid waste particularly come from beef cattle production. Therefore, the objective of study was to determine the effect of Spirulina population densities toward the reduction of BOD5 and COD of beef cattle slurry. This study was done experimentally based on Completely Randomized Design with four treatments of population density in term of dilution factors, viz.D1 = 10, D2 = 10, D3=10 and D4= 10. Each treatment was in four replicates. The effect of ...

Microalgae in the wild often form consortia with other species promoting their own health and resource foraging opportunities. The recent application of microalgae cultivation and deployment in commercial photobioreactors (PBR) so far has focussed on single species of algae, resulting in multi-species consortia being largely unexplored. Reviewing the current status of PBR ecological habitat, this article argues in favor of further investigation into algal communication with conspecifics and interspecifics, including other strains of microalgae and bacteria. These mutualistic species form the 'phycosphere': the microenvironment surrounding microalgal cells, potentiating the production of certain metabolites through biochemical interaction with cohabitating microorganisms. A better understanding of the phycosphere could lead to novel PBR configurations, capable of incorporating algal-microbial consortia, potentially proving more effective than single-species algal systems.

Red blood cells mature within the erythroblastic island (EI) niche that consists of specialized macrophages surrounded by differentiating erythroblasts. Here we establish an in vitro system to model the human EI niche using macrophages that are derived from human induced pluripotent stem cells (iPSCs), and are also genetically programmed to an EI-like phenotype by inducible activation of the transcription factor, KLF1. These EI-like macrophages increase the production of mature, enucleated erythroid cells from umbilical cord blood derived CD34+ haematopoietic progenitor cells and iPSCs; this enhanced production is partially retained even when the contact between progenitor cells and macrophages is inhibited, suggesting that KLF1-induced secreted proteins may be involved in this enhancement. Lastly, we find that the addition of three secreted factors, ANGPTL7, IL-33 and SERPINB2, significantly enhances the production of mature enucleated red blood cells. Our study thus contributes to...

Glucocorticoids are endogenous steroid hormones that regulate several biological functions including proliferation, differentiation and apoptosis in numerous cell types in response to stress. Synthetic glucocorticoids, such as dexamethasone (Dex) are used to treat a variety of diseases ranging from allergy to depression. Glucocorticoids exert their effects by passively entering into cells and binding to a specific Glucocorticoid Receptor (GR) present in the cytoplasm. Once activated by its ligand, GR may elicit cytoplasmic (mainly suppression of p53), and nuclear (regulation of transcription of GR responsive genes), responses. Human GR is highly polymorphic and may encode &gt; 260 different isoforms. This polymorphism is emerging as the leading cause for the variability of phenotype and response to glucocorticoid therapy observed in human populations. Studies in mice and clinical observations indicate that GR controls also the response to erythroid stress. This knowledge has been ex...