IWWT

Electrochemical harvesting of algae employing non-sacrificial carbon electrode. Anode depletion and accompanying metallic contamination can be completely avoided. Effect of operating condition on lipid recovery and composition are evaluated. Electrochemical process has no adverse effect on the lipid extraction process. Striking recovery at low energy consumption by applying nonsacrificial electrodes.

Biorefinery has emerged as a new concept to derive more than one utility product from biomass. The products from biorefinery include one or more biofuels (biodiesel, bioethanol, biomethane, and biohydrogen) along with other energy sources (syngas and bio-oil), pharmaceutical products, and commercially important chemicals. Biorefineries, thus could simultaneously produce biofuels, bio-based chemicals, heat, and power. The biomass production and its utilization as biofuel has a higher water footprint (WF) than fossil derived fuel. The biorefinery approach has the potential to bring down the WF. Similarly, biorefinery approach has the potential to bring down the carbon footprint. The value added product derived from biorefinery basket includes pigments, nutraceuticals, and bioactive compounds. The use of industrial refusals for biomass production includes wastewater as nutrient medium and utilization of flue gases (CO 2 ) as the carbon source for culture of microalgae. These processes have the potential to reduce fresh WF and carbon footprint.

h i g h l i g h t s Electrochemical harvesting of algae employing non-sacrificial carbon electrode. Anode depletion and accompanying metallic contamination can be completely avoided. Effect of operating condition on lipid recovery and composition are evaluated. Electrochemical process has no adverse effect on the lipid extraction process. Striking recovery at low energy consumption by applying nonsacrificial electrodes.

The production of biodiesel can be accomplished using a variety of feedstock sources. Plant and microalgae based feedstocks are prominent and are studied extensively. Plant based feedstocks cultivated as monoculture on wastelands and trees in forests can cater towards partial fulfillment of feedstock requirements for biodiesel industry. Synthesis of biodiesel from microalgal oil has gathered immense interest and has potential to cater to the increasing feedstocks demands of the biodiesel industry. The major advantage offered by microalgal oil, as compared to plant based oils, is its potential for culture on non-arable land. Despite of the advantages of microalgal oil as a feedstock for biodiesel, there are constraints that have to be overcome in order to make it economical and sustainable. Sustainable approaches for both the plant and microalgae as feedstocks have been drawn. Despite there being several plant species, few have been found to be desirable as feedstocks for biodiesel production based on their lipid profiles. Among the microalgae, there are thousands of species and several of these have been cultured for extracting the oil to explore their feasibility in utilization as biodiesel feedstocks. Though, several of the microalgal species have shown potential for high biomass growth and lipid productivity, only a few have been found to provide a high biodiesel yield and conversion. Due to the several steps involved in the extraction of oil which are energy intensive, the cost of biodiesel from microalgal oil is high as compared with that obtained from the plant oils. A sustainable approach for utilizing plant and microalgal oils as feedstocks for biodiesel have been discussed. The emerging cost effective methods in production of biodiesel have been described. The energy return and greenhouse gas emissions from biodiesel have been outlined. Together, the plant oil and microalgal oil can offer potential source of feedstocks for the production of biodiesel.

h i g h l i g h t s Non-sacrificial electrodes were applied for electrochemical harvesting of microalgae. Anode depletion and metallic contamination of biomass can be completely avoided. Addition of electrolyte is beneficial for the electrochemical harvesting process. ECH process has no adverse effect on the lipid extraction process. Electrolyte addition improves lipid extraction.

Harvesting of microalgal biomass is still a bottleneck to its commercial scale application, due to small cell size, low culture densities, colloidal stability and thus unfavourable economics. Centrifugation is an efficient technique but the high energy consumption makes it unsuitable for low value microalgal products. Chemical flocculation and filtration are inefficient and time consuming methods for harvesting of small size microalgae. In this study, an electrochemical harvesting (ECH) process was assessed for the harvesting of a small size microalga Ankistrodesmus falcatus by using non-sacrificial carbon electrodes. Harvesting efficiency of ECH was compared to centrifugation and flocculation using alum and chitosan. The highest recovery efficiency was obtained by centrifugation (93% after 15 min) followed by ECH process (91% after 30 min), alum (86% after 60 min) and chitosan (55% after 60 min). However, the energy consumption of ECH process (1.76 kWh kg −1) was much lower than the centrifugation process (65.34 kWh kg −1). The biochemical composition of harvested biomass was also assessed, and it was found that the ECH process has no deteriorating effect on the quality of biomass. High recovery efficiency, low energy consumption and the use of non-sacrificial electrodes make ECH a sustainable harvesting technique for small size microalgae.

Banana pseudostem (BPS) is an agricultural waste with a high holocellulose content, which, upon hydrolysis, releases fermentable sugars that can be used for bioethanol production. Different pretreatment methods, namely, 3% (w/v) NaOH, 5% (v/v) H2SO4, and liquid hot water, applied on the BPS resulted in the availability of 52%, 48%, and 25% cellulose after treatment, respectively. Saccharification of the pretreated BPS with 10 FPU/g dry solids (29.3 mg protein/g d.s) crude enzyme from Trichoderma harzianum LMLBP07 13-5 at 50°C and a substrate loading of 10 to 15% released 3.8 to 21.8 g/L and from T. longibrachiatum LMLSAUL 14-1 released 5.4 to 43.5 g/L glucose to the biomass. Ethanol was produced through separate hydrolysis and fermentation (SHF) of alkaline pretreated BPS hydrolysate using Saccharomyces cerevisiae UL01 at 30°C and 100 rpm. Highest ethanol produced was 17.6 g/L. Banana pseudostem was shown as a potentially cheap substrate for bioethanol production.

Sclerocarya birrea (Morula tree) is one of the indigenous trees bearing wild fruits with various applications in the African communities. Wine is a globally known beverage usually made from grapes; however, recently, other fruits, including wild fruits with a considerable amount of sugars, can be used for making wines. The marula fruit wine is also important in many communities for cultural activities and can be enjoyed by people of varying age groups depending on the age of the product. In recent years, there has been growing interest in shifting from traditional marula winemaking to developing technologies for the marula winemaking process and commercialisation. The process of marula winemaking is similar to the production of grape wines, which entails collection, selection and washing of the fruits; extraction of the juice and mashing; formation and removal of the scum; and ultimately spontaneous fermentation of the resulting juice. The new process in marula winemaking would take...

The production cost of cellulases is regarded as a limiting factor in the cellulosic ethanol production chain. Trichoderma and Aspergillus species were used to produce cellulases through solid-state fermentation (SSF) utilizing banana pseudostem (BPS) as a carbon source. The production of cellulases was investigated at various substrate moisture contents (65–80%), incubation temperatures (30–40 °C), substrate pre-treatment methods (3% w/v NaOH, 5% v/v H2SO4, and water), and with different co-culturing of microorganisms. Trichoderma longibrachiatum LMLSAUL 14-1 produced the maximum total cellulase (75 FPU/g d.s), endoglucanase (11.35 U/g d.s), and β-glucosidase (235.83 U/g d.s) activities at a 75% moisture content of the untreated BPS at 30 °C in static culture. Pre-treatment of BPS improved the production of specific enzymes. Aspergillus fumigatus LMLPS 13-4 produced more β-glucosidase (259.8 U/g d.s) when grown on acid-pre-treated BPS, whereas T. harzianum LMLBP07 13-5 produced the...

Cellulases are a group of hydrolytic enzymes that break down cellulose to glucose units. These enzymes are used in the food, beverage, textile, pulp, and paper and the biofuel industries. The aim of this study was to isolate fungi from natural compost and produce cellulases in submerged fermentation (SmF). Initial selection was based on the ability of the fungi to grow on agar containing Avicel followed by cellulase activity determination in the form of endoglucanase and total cellulase activity. Ten fungal isolates obtained from the screening process showed good endoglucanase activity on carboxymethyl cellulose-Congo Red agar plates. Six of the fungal isolates were selected based on high total cellulase activity and identified as belonging to the genera Trichoderma and Aspergillus. In SmF of synthetic media with an initial pH of 6.5 at 30°C Trichoderma longibrachiatum LMLSAUL 14-1 produced total cellulase activity of 8 FPU/mL and endoglucanase activity of 23 U/mL whilst Trichoderma...

Purpose The microorganisms that possess diverse and improved traits for biotechnological applications provide an opportunity to address some of the current industrial challenges such as sustainability of fuel energy and food. The aim of this study was to evaluate the potential of yeast isolates from sugarcane bagasse for single oil production. Methods Oleaginocity of the yeasts was confirmed through gravimetric analysis of lipids, Nile red, sulfo-phosphovanillin (SPV) and gas chromatography method for fatty acid methyl esters (FAME). Identification of the selected yeasts was carried out through 5.8S of the ribosomal internal transcribed spacer, ITS and 26S ribosomal DNA (rDNA) sequences. Results The yeast isolates accumulated lipids between 28% and 67% of the dry cell weight, and 22%-33% based on SPV assay, qualifying them as oleaginous yeasts. the isolated yeasts were identified as Candida ethanolica and Pichia manshuriica. Conclusion The lipids contained high level of fatty acids ...