I would like to thank to all people who help and encourage me during the completion of my thesis,... more I would like to thank to all people who help and encourage me during the completion of my thesis, especially to all my classmates and PhD students in the Process Integration Department. Last but not least, my warmest thanks to my parents. Without their constant love, understanding and encouragement this thesis would never been possible.
Journal of Tropical Resources and Sustainable Science (JTRSS), 2021
Understanding of the correlative effects of combined variables on the growth rate of the cyanobac... more Understanding of the correlative effects of combined variables on the growth rate of the cyanobacteria is fundamental to the exploitation of cyanobacteria as a biological mechanism to produce biofuels. Cyanobacteria (blue-green algae) are phototrophic microorganisms that offers attractive benefits, among which is a direct conversion of CO2 to a range of valuable products such as carbon-based biofuels. One model of cyanobacteria species is the cyanobacterium Synechococcus sp. PCC 7002. This paper describes the model developed to investigate the combined impacts of the variables on the growth of the Synechococcus sp. PCC 7002. The variables understudy include the temperature of the media, light intensity, the concentration of NaNO3, and the concentration of the NPK. The data is obtained from a lab scale study in which the Synechococcus sp. PCC 7002 underwent mutagenesis procedures. It is hypotheses that certain combination of the variables plays a key role in determining the growth ra...
The need of energy from fossil fuel has become a global issue that is challenging to the humanity... more The need of energy from fossil fuel has become a global issue that is challenging to the humanity due to its high demand. However, fossil fuel is a non renewable form of energy which, in turn, will lead to the energy scarcity. As a matter of fact, researcher has put a strong emphasize to find the alternative source of energy. Biohydrogen produced from the waste has a potential to be an alternative energy for the future. Numerous papers have discussed biohydrogen process technology using several methods such as dark fermentation, photofermentation and integration of both methods. Unfortunately, there is still lack of papers addressing specifically on what is the most suitable bacteria for biohydrogen production. On the other hand, dark fermentative bacterium is a robust bacterium. Dark fermentative bacteria are reported to have capability in consuming sludge and waste to synthesize biohydrogen. Therefore, this paper aims to discuss the correlation between dark fermentative bacteria a...
Liquid smoking in preserving protein-based foods such as meat, fish and cheese has been increasin... more Liquid smoking in preserving protein-based foods such as meat, fish and cheese has been increasingly utilized, giving a pleasant flavour and inhibit the effects of pathogens. Liquid smoke is the product of pyrolysis system and distillation process. The smoke produced by incomplete combustion reaction involves the decomposition of polymers into low molecular weight of organic compound due to the effect of oxidation reaction, polymerization and condensation. Coconut Shell Liquid Smoke (CSLS) has been reported to be safe and not toxic to animals and human health. In this study, coconut shells are used to produce the liquid smoke using pyrolysis and condensation processes. The main objective of this research is to produce liquid smoke from coconut shell using 230 L pilot plant of pyrolysis system. The process conditions and characteristics for high yield of coconut shell liquid smoke production were determined. The composition and characteristics of coconut shell liquid smoke was also a...
Scarcity of petroleum and constant concern over environmental problems caused by diesel fuels has... more Scarcity of petroleum and constant concern over environmental problems caused by diesel fuels has promoted production of biodiesel from renewable sources. Biodiesel synthesized from transesterification methods in the presence of catalyst or enzyme requires huge amount of solvent, particularly from alcohol to affirm high production yield. Inevitably, the process results in bulky waste that demands appropriate attention. In attempt to tackle the problem, ionic liquid has been identified to be the most potential substitute for conventional catalyst and solvent required in the biodiesel conversion. Ionic liquid that is widely known as ‘green chemical’ can be synthesized to meet reaction requirement by careful selection of anion and cations, with correct proportion of each to produce desired mixture. This paper reviews recent applications of ionic liquid in biodiesel production as catalyst, solvent and co-solvent. Since there are few ways in which ionic liquid can be categorized, this pa...
Utilization of modified-polyHIPE polymer matrix in the immobilization cell system is probably can... more Utilization of modified-polyHIPE polymer matrix in the immobilization cell system is probably can substitute conventional cell matrix. The confined microenvironment was designed to promote the bacterium growth and its metabolic activity. The applied forced-flow seeding technique yielded a more uniform distribution of cells within the polymeric support, which also helps to improve nutrient transport. This also prevents significant growth of cells around the outer surface of matrix. The microstructure of the matrix with respect to its physico-chemical characteristics, which include appropriate pore and interconnect sizes as well as surface chemistry (i.e. hydrophobic, hydrophilic), are very important with respect to the flow of nutrients and waste material and also for cell migration. As a result, the developed immobilized matrix can be performed effectively and essential in the area of bioprocess development specifically for microbial fermentations.
This paper reviews reported studies on the hydrolysis of starch especially sago via acid and enzy... more This paper reviews reported studies on the hydrolysis of starch especially sago via acid and enzyme. The review begins with overview of sago palm and the starch industry, followed by process of extracting the starch from sago pith. Physicochemical properties of sago starch were tabulated for better understanding of hydrolysis process. Factors or process condition influencing hydrolysis process is discussed based on results from previous researches. Advantages and disadvantages of each hydrolysis is also discussed. Generally, there are very few researches dedicated on sago starch as compared to other starches. It can be concluded that, enzyme hydrolysis gives higher yield at milder process conditions. However, the reaction rate of enzyme hydrolysis is still low compared to acid hydrolysis.
Aim: Microalgae is one of the bioremediation agents in wastewater treatment due to its ability to... more Aim: Microalgae is one of the bioremediation agents in wastewater treatment due to its ability to degrade nutrients and organic compounds. Several studies reported that co-cultivation of microalgae and bacteria, i.e. Microalgae Growth Promoting Bacteria (MGPB) could improve the nutrients removal process. This MGPB helps to degrade complex nutrient compounds into smaller components before being taken up by microalgae. The objective of this study is to investigate the effectiveness of co-cultured (microalgae and bacteria) system compared to axenic microalgae system in the removal of major nutrients (ammonium and phosphorus) and chemical oxygen demand (COD) in synthetic wastewater. Methodology and result: In this study, two different strains of microalgae (Chlorella vulgaris and Scenedesmus quadricauda) were each co-cultured with a MGPB (Azospirillum brasilense) and their effectiveness in the removal of major nutrients and COD were compared. The results show that, the nutrients and COD removal were higher in cocultured system compared to the axenic microalgae under similar cultivation conditions for both microalgae strains. Higher percentage removal was obtained from co-cultured C. vulgaris compared to that from co-cultured S. quadricauda which were 86% and 48%, 44% and 31%, 62% and 35% for ammonium, phosphorus and COD removal respectively. Conclusion, significance and impact of study: The findings of this study demonstrate the potential of the co-culture of C. vulgaris and A. brasilense to be applied in wastewater treatment, specifically replacing the aerobic digestion process in secondary stage of conventional wastewater treatment. This study provides an important insight into developing an efficient and environmental friendly method to treat wastewater by incorporating the green technology in the treatment system.
Photosynthetic microorganism such as cyanobacteria emerge attractive due to its diverse potential... more Photosynthetic microorganism such as cyanobacteria emerge attractive due to its diverse potential uses in the biotechnology field. It is also useful for CO 2 sequestration and biofuel production. However different CO 2 concentrations supplied to the culture affect cell growth and lipid production in different ways. This paper focuses on the influences of CO 2 concentrations (i.e. 15%(v/v) to 30% (v/v)), which was supplied for 30 minutes every day (i.e. total of 7 days of experiment duration) to the culture system, on the growth of Synechococccus sp. (PCC 7002 strain), total lipid production, culture pH and CO 2 removal. The results showed that the highest growth and total lipid were obtained when the culture was supplied with 15%(v/v) and 30%(v/v) of CO 2 , respectively. The CO 2 removal was decreasing when the concentration was at 30%(v/v). Finally, the pH of cultures reduced as the CO 2 concentration increased.
The concern about our dependency on non-renewable resources and overwhelming environmental issues... more The concern about our dependency on non-renewable resources and overwhelming environmental issues such as pollution caused by non-degradable packaging materials has prompted researchers to come up with alternatives to solve this problem. Thermoplastic polylactic acid (PLA) has been gaining interest due to its versatility and easy processability, thus this study was carried out to find out the properties of PLA reinforced with pineapple fibers. However, surface of the natural fibers need to be treated for better properties enhancement in the polymer matrices. Considering this, the fibers were treated with 10% (w/v) concentration of potassium hydroxide (KOH) and then continued for mixing with PLA at a fixed ratio of plasticizer by using internal mixer, and then the composites were prepared into sheet via hot press. Characterization for the mechanical and morphological was conducted by using tensile testing and scanning electron microscopy, respectively. After the analysis, it is found...
Recently, mutagenesis on cyanobacteria has been performed to enhance carbon dioxide (CO2) bio-mit... more Recently, mutagenesis on cyanobacteria has been performed to enhance carbon dioxide (CO2) bio-mitigation. The physical and chemical mutagens have been introduced on cyanobacteria to induce genetic mutation. Physical mutagen includes electromagnetic radiation, such as gamma rays, x-rays, and ultraviolet (UV) light, while the chemical mutagen includes are ethyl methanesulphonate (EMS), and N-methyl-N?-nitro-N-nitrosoguanidine (MNNG). Different types of mutagen, concentration, incubation period and temperature affect the rate of mutagenesis. As a result, various kinds of observation were produced. Thus, this review aims at providing an updated account of the research progress in mutagenesis on cyanobacteria and its application in CO2 mitigation enhancement.
Prediction of significant factors in the production of ethanol by ragi tapai co-culture using Tag... more Prediction of significant factors in the production of ethanol by ragi tapai co-culture using Taguchi methodology
The usage of non-degradable polymer as the main matrix for a cosmetic patch raises concern, as it... more The usage of non-degradable polymer as the main matrix for a cosmetic patch raises concern, as it can cause environmental pollution when discarded in landfill. Thus, biodegradable polylactic acid (PLA) was chosen in this study, as PLA has non-toxic properties and similar mechanical properties to conventional plastic materials. An active ingredient in a cosmetic patch serves the purpose of providing beneficial ingredients to the skin; therefore, phycocyanin, an extract from spirulina, was chosen, as it possesses antioxidant and anti-inflammatory properties. Alginate was also incorporated with the phycocyanin for fabrication onto the PLA matrix. A preliminary study was first carried out to identify the antioxidant properties and cytotoxic effect of the phycocyanin on skin cells. It was observed that phycocyanin had no cytotoxic effect on the skin and showed good antioxidant activity. PLA/phycocyanin–alginate composite was fabricated using a solvent casting method, and optimization of ...
The concentrations of nutrient elements together with several physical parameters were screened t... more The concentrations of nutrient elements together with several physical parameters were screened to find out the significant factors for the production of L-asparaginase from newly isolated strain, Bacillus sp. from Sg Klah, Hot Spring, Perak. Then, the significant factors were optimized for enhancing L-asparaginase production from the bacterium strain. Two statistical designs, Two Level Factorial Design and Face Centered Composite Design (FCCD), Design expert @version 8.0 were employed in screening and optimization of the process variables, respectively. The results for all experiment runs were analyzed by analysis of variance (ANOVA). Peptone (nitrogen source) concentration and temperature were found as significant factors, positively influenced the production of L-asparaginase. The two factors were then optimized to increase the desired enzyme production. The optimum peptone concentration and the temperature were found at 1.4 g/L and 30ºC, respectively. The L-asparaginase producti...
IOP Conference Series: Materials Science and Engineering
Sago wastewater (SWW) is one of by-products from sago starch industry. In most practice, SWW is d... more Sago wastewater (SWW) is one of by-products from sago starch industry. In most practice, SWW is discharged to the nearby rivers. As it contains high amount of organic compounds, usual practice of disposing the wastewater will cause a detrimental impact to the environment. The organic compounds found in SWW such as starch can be utilized as substrate for biofuel and biohydrogen fermentations. However, this starch needs to first undergo pretreatment process to breakdown its complex sugars to the simpler ones. This study aimed to investigate the effect of microwave-assisted acid pretreatment of SWW for fermentable sugar (glucose) production using sulphuric acid (H2SO4). Three parameters that influenced microwaveassisted acid pretreatment were chosen for optimization which are residence time (3-9 min), acid concentration (0.2-0.6 M) and solid loading (5-15% w/v). Faced Centered Central Composite Design (FCCCD) tool under Response Surface Methodology (RSM) in Design Expert v9.0.6.2 software was used for designing the experiments and optimization purposes. The response was the amount of glucose converted (g/L). The maximum fermentable sugar produced was 3.920 g/L, obtained at 9 minutes with 15% solid loading using 0.6 M of H2SO4. Then, the kinetic study of acid hydrolysis was performed by following the first order reaction kinetics. The rate constant of reaction obtained was 0.1684 min-1. It can be concluded that microwave-assisted acid pretreatment of SWW is able to produce high amount of fermentable sugar within a short residence time.
Desaru is a popular tourist destination located on the east coast of the state of Johor. The area... more Desaru is a popular tourist destination located on the east coast of the state of Johor. The area has been identified for further development to enhance tourism. This presents a pollution risk to its surrounding watercourses. The purpose of this study was to assess the potential risk of contamination towards rivers located in the crux of the development region, namely the Terumpah, Che Minah, Semangar, Beluntu, Penawar Besar, and Mertang Besar Rivers. Water quality and hydraulic measurements were made at these rivers, with the intention of developing a numerical model. The model results showed deterioration in BOD5 and NH3-N in the Semangar River, up to 4.0 mg/dm 3 and 0.34 mg/dm 3 , respectively. The Beluntu River experienced the highest degradation, to about 14.0 mg/dm 3 of BOD5 and 0.8 mg/dm 3 of NH3-N. The waste assimilative capacity (WAC) for the Matang Besar, Che Minah and Beluntu Rivers were very limited, with a class III BOD5 limit of 15, 43, and 10 kg/day, respectively, whereas the Terumpah River is not able to accept any BOD load without breaching the same threshold.
Biohydrogen has been recognized to be one of the future renewable energy sources and has the pote... more Biohydrogen has been recognized to be one of the future renewable energy sources and has the potential in solving the greenhouse effects. In this study, Enterobacter aerogenes (E. aerogenes) was used as the biohydrogen producer via dark fermentation process using sago wastewater as the substrate. However, pretreatment of sago wastewater is required since it consists of complex sugars that cannot be utilized directly by the bacteria. This study aimed to use acid pretreatment method to produce high amount of glucose from sago wastewater. Three different types of acid: sulfuric acid (H2SO4); hydrochloric acid (HCl) and nitric acid (HNO3) were screened for the best acid in producing a maximum amount of glucose. H2SO4 gave the highest amount of glucose which was 9.406 g/L. Design of experiment was done using Face-centred Central Composite Design (FCCCD) tool under Response Surface Methodology (RSM) in Design Expert 9 software. The maximum glucose (9.138 g/L) was recorded using 1 M H2SO4 ...
I would like to thank to all people who help and encourage me during the completion of my thesis,... more I would like to thank to all people who help and encourage me during the completion of my thesis, especially to all my classmates and PhD students in the Process Integration Department. Last but not least, my warmest thanks to my parents. Without their constant love, understanding and encouragement this thesis would never been possible.
Journal of Tropical Resources and Sustainable Science (JTRSS), 2021
Understanding of the correlative effects of combined variables on the growth rate of the cyanobac... more Understanding of the correlative effects of combined variables on the growth rate of the cyanobacteria is fundamental to the exploitation of cyanobacteria as a biological mechanism to produce biofuels. Cyanobacteria (blue-green algae) are phototrophic microorganisms that offers attractive benefits, among which is a direct conversion of CO2 to a range of valuable products such as carbon-based biofuels. One model of cyanobacteria species is the cyanobacterium Synechococcus sp. PCC 7002. This paper describes the model developed to investigate the combined impacts of the variables on the growth of the Synechococcus sp. PCC 7002. The variables understudy include the temperature of the media, light intensity, the concentration of NaNO3, and the concentration of the NPK. The data is obtained from a lab scale study in which the Synechococcus sp. PCC 7002 underwent mutagenesis procedures. It is hypotheses that certain combination of the variables plays a key role in determining the growth ra...
The need of energy from fossil fuel has become a global issue that is challenging to the humanity... more The need of energy from fossil fuel has become a global issue that is challenging to the humanity due to its high demand. However, fossil fuel is a non renewable form of energy which, in turn, will lead to the energy scarcity. As a matter of fact, researcher has put a strong emphasize to find the alternative source of energy. Biohydrogen produced from the waste has a potential to be an alternative energy for the future. Numerous papers have discussed biohydrogen process technology using several methods such as dark fermentation, photofermentation and integration of both methods. Unfortunately, there is still lack of papers addressing specifically on what is the most suitable bacteria for biohydrogen production. On the other hand, dark fermentative bacterium is a robust bacterium. Dark fermentative bacteria are reported to have capability in consuming sludge and waste to synthesize biohydrogen. Therefore, this paper aims to discuss the correlation between dark fermentative bacteria a...
Liquid smoking in preserving protein-based foods such as meat, fish and cheese has been increasin... more Liquid smoking in preserving protein-based foods such as meat, fish and cheese has been increasingly utilized, giving a pleasant flavour and inhibit the effects of pathogens. Liquid smoke is the product of pyrolysis system and distillation process. The smoke produced by incomplete combustion reaction involves the decomposition of polymers into low molecular weight of organic compound due to the effect of oxidation reaction, polymerization and condensation. Coconut Shell Liquid Smoke (CSLS) has been reported to be safe and not toxic to animals and human health. In this study, coconut shells are used to produce the liquid smoke using pyrolysis and condensation processes. The main objective of this research is to produce liquid smoke from coconut shell using 230 L pilot plant of pyrolysis system. The process conditions and characteristics for high yield of coconut shell liquid smoke production were determined. The composition and characteristics of coconut shell liquid smoke was also a...
Scarcity of petroleum and constant concern over environmental problems caused by diesel fuels has... more Scarcity of petroleum and constant concern over environmental problems caused by diesel fuels has promoted production of biodiesel from renewable sources. Biodiesel synthesized from transesterification methods in the presence of catalyst or enzyme requires huge amount of solvent, particularly from alcohol to affirm high production yield. Inevitably, the process results in bulky waste that demands appropriate attention. In attempt to tackle the problem, ionic liquid has been identified to be the most potential substitute for conventional catalyst and solvent required in the biodiesel conversion. Ionic liquid that is widely known as ‘green chemical’ can be synthesized to meet reaction requirement by careful selection of anion and cations, with correct proportion of each to produce desired mixture. This paper reviews recent applications of ionic liquid in biodiesel production as catalyst, solvent and co-solvent. Since there are few ways in which ionic liquid can be categorized, this pa...
Utilization of modified-polyHIPE polymer matrix in the immobilization cell system is probably can... more Utilization of modified-polyHIPE polymer matrix in the immobilization cell system is probably can substitute conventional cell matrix. The confined microenvironment was designed to promote the bacterium growth and its metabolic activity. The applied forced-flow seeding technique yielded a more uniform distribution of cells within the polymeric support, which also helps to improve nutrient transport. This also prevents significant growth of cells around the outer surface of matrix. The microstructure of the matrix with respect to its physico-chemical characteristics, which include appropriate pore and interconnect sizes as well as surface chemistry (i.e. hydrophobic, hydrophilic), are very important with respect to the flow of nutrients and waste material and also for cell migration. As a result, the developed immobilized matrix can be performed effectively and essential in the area of bioprocess development specifically for microbial fermentations.
This paper reviews reported studies on the hydrolysis of starch especially sago via acid and enzy... more This paper reviews reported studies on the hydrolysis of starch especially sago via acid and enzyme. The review begins with overview of sago palm and the starch industry, followed by process of extracting the starch from sago pith. Physicochemical properties of sago starch were tabulated for better understanding of hydrolysis process. Factors or process condition influencing hydrolysis process is discussed based on results from previous researches. Advantages and disadvantages of each hydrolysis is also discussed. Generally, there are very few researches dedicated on sago starch as compared to other starches. It can be concluded that, enzyme hydrolysis gives higher yield at milder process conditions. However, the reaction rate of enzyme hydrolysis is still low compared to acid hydrolysis.
Aim: Microalgae is one of the bioremediation agents in wastewater treatment due to its ability to... more Aim: Microalgae is one of the bioremediation agents in wastewater treatment due to its ability to degrade nutrients and organic compounds. Several studies reported that co-cultivation of microalgae and bacteria, i.e. Microalgae Growth Promoting Bacteria (MGPB) could improve the nutrients removal process. This MGPB helps to degrade complex nutrient compounds into smaller components before being taken up by microalgae. The objective of this study is to investigate the effectiveness of co-cultured (microalgae and bacteria) system compared to axenic microalgae system in the removal of major nutrients (ammonium and phosphorus) and chemical oxygen demand (COD) in synthetic wastewater. Methodology and result: In this study, two different strains of microalgae (Chlorella vulgaris and Scenedesmus quadricauda) were each co-cultured with a MGPB (Azospirillum brasilense) and their effectiveness in the removal of major nutrients and COD were compared. The results show that, the nutrients and COD removal were higher in cocultured system compared to the axenic microalgae under similar cultivation conditions for both microalgae strains. Higher percentage removal was obtained from co-cultured C. vulgaris compared to that from co-cultured S. quadricauda which were 86% and 48%, 44% and 31%, 62% and 35% for ammonium, phosphorus and COD removal respectively. Conclusion, significance and impact of study: The findings of this study demonstrate the potential of the co-culture of C. vulgaris and A. brasilense to be applied in wastewater treatment, specifically replacing the aerobic digestion process in secondary stage of conventional wastewater treatment. This study provides an important insight into developing an efficient and environmental friendly method to treat wastewater by incorporating the green technology in the treatment system.
Photosynthetic microorganism such as cyanobacteria emerge attractive due to its diverse potential... more Photosynthetic microorganism such as cyanobacteria emerge attractive due to its diverse potential uses in the biotechnology field. It is also useful for CO 2 sequestration and biofuel production. However different CO 2 concentrations supplied to the culture affect cell growth and lipid production in different ways. This paper focuses on the influences of CO 2 concentrations (i.e. 15%(v/v) to 30% (v/v)), which was supplied for 30 minutes every day (i.e. total of 7 days of experiment duration) to the culture system, on the growth of Synechococccus sp. (PCC 7002 strain), total lipid production, culture pH and CO 2 removal. The results showed that the highest growth and total lipid were obtained when the culture was supplied with 15%(v/v) and 30%(v/v) of CO 2 , respectively. The CO 2 removal was decreasing when the concentration was at 30%(v/v). Finally, the pH of cultures reduced as the CO 2 concentration increased.
The concern about our dependency on non-renewable resources and overwhelming environmental issues... more The concern about our dependency on non-renewable resources and overwhelming environmental issues such as pollution caused by non-degradable packaging materials has prompted researchers to come up with alternatives to solve this problem. Thermoplastic polylactic acid (PLA) has been gaining interest due to its versatility and easy processability, thus this study was carried out to find out the properties of PLA reinforced with pineapple fibers. However, surface of the natural fibers need to be treated for better properties enhancement in the polymer matrices. Considering this, the fibers were treated with 10% (w/v) concentration of potassium hydroxide (KOH) and then continued for mixing with PLA at a fixed ratio of plasticizer by using internal mixer, and then the composites were prepared into sheet via hot press. Characterization for the mechanical and morphological was conducted by using tensile testing and scanning electron microscopy, respectively. After the analysis, it is found...
Recently, mutagenesis on cyanobacteria has been performed to enhance carbon dioxide (CO2) bio-mit... more Recently, mutagenesis on cyanobacteria has been performed to enhance carbon dioxide (CO2) bio-mitigation. The physical and chemical mutagens have been introduced on cyanobacteria to induce genetic mutation. Physical mutagen includes electromagnetic radiation, such as gamma rays, x-rays, and ultraviolet (UV) light, while the chemical mutagen includes are ethyl methanesulphonate (EMS), and N-methyl-N?-nitro-N-nitrosoguanidine (MNNG). Different types of mutagen, concentration, incubation period and temperature affect the rate of mutagenesis. As a result, various kinds of observation were produced. Thus, this review aims at providing an updated account of the research progress in mutagenesis on cyanobacteria and its application in CO2 mitigation enhancement.
Prediction of significant factors in the production of ethanol by ragi tapai co-culture using Tag... more Prediction of significant factors in the production of ethanol by ragi tapai co-culture using Taguchi methodology
The usage of non-degradable polymer as the main matrix for a cosmetic patch raises concern, as it... more The usage of non-degradable polymer as the main matrix for a cosmetic patch raises concern, as it can cause environmental pollution when discarded in landfill. Thus, biodegradable polylactic acid (PLA) was chosen in this study, as PLA has non-toxic properties and similar mechanical properties to conventional plastic materials. An active ingredient in a cosmetic patch serves the purpose of providing beneficial ingredients to the skin; therefore, phycocyanin, an extract from spirulina, was chosen, as it possesses antioxidant and anti-inflammatory properties. Alginate was also incorporated with the phycocyanin for fabrication onto the PLA matrix. A preliminary study was first carried out to identify the antioxidant properties and cytotoxic effect of the phycocyanin on skin cells. It was observed that phycocyanin had no cytotoxic effect on the skin and showed good antioxidant activity. PLA/phycocyanin–alginate composite was fabricated using a solvent casting method, and optimization of ...
The concentrations of nutrient elements together with several physical parameters were screened t... more The concentrations of nutrient elements together with several physical parameters were screened to find out the significant factors for the production of L-asparaginase from newly isolated strain, Bacillus sp. from Sg Klah, Hot Spring, Perak. Then, the significant factors were optimized for enhancing L-asparaginase production from the bacterium strain. Two statistical designs, Two Level Factorial Design and Face Centered Composite Design (FCCD), Design expert @version 8.0 were employed in screening and optimization of the process variables, respectively. The results for all experiment runs were analyzed by analysis of variance (ANOVA). Peptone (nitrogen source) concentration and temperature were found as significant factors, positively influenced the production of L-asparaginase. The two factors were then optimized to increase the desired enzyme production. The optimum peptone concentration and the temperature were found at 1.4 g/L and 30ºC, respectively. The L-asparaginase producti...
IOP Conference Series: Materials Science and Engineering
Sago wastewater (SWW) is one of by-products from sago starch industry. In most practice, SWW is d... more Sago wastewater (SWW) is one of by-products from sago starch industry. In most practice, SWW is discharged to the nearby rivers. As it contains high amount of organic compounds, usual practice of disposing the wastewater will cause a detrimental impact to the environment. The organic compounds found in SWW such as starch can be utilized as substrate for biofuel and biohydrogen fermentations. However, this starch needs to first undergo pretreatment process to breakdown its complex sugars to the simpler ones. This study aimed to investigate the effect of microwave-assisted acid pretreatment of SWW for fermentable sugar (glucose) production using sulphuric acid (H2SO4). Three parameters that influenced microwaveassisted acid pretreatment were chosen for optimization which are residence time (3-9 min), acid concentration (0.2-0.6 M) and solid loading (5-15% w/v). Faced Centered Central Composite Design (FCCCD) tool under Response Surface Methodology (RSM) in Design Expert v9.0.6.2 software was used for designing the experiments and optimization purposes. The response was the amount of glucose converted (g/L). The maximum fermentable sugar produced was 3.920 g/L, obtained at 9 minutes with 15% solid loading using 0.6 M of H2SO4. Then, the kinetic study of acid hydrolysis was performed by following the first order reaction kinetics. The rate constant of reaction obtained was 0.1684 min-1. It can be concluded that microwave-assisted acid pretreatment of SWW is able to produce high amount of fermentable sugar within a short residence time.
Desaru is a popular tourist destination located on the east coast of the state of Johor. The area... more Desaru is a popular tourist destination located on the east coast of the state of Johor. The area has been identified for further development to enhance tourism. This presents a pollution risk to its surrounding watercourses. The purpose of this study was to assess the potential risk of contamination towards rivers located in the crux of the development region, namely the Terumpah, Che Minah, Semangar, Beluntu, Penawar Besar, and Mertang Besar Rivers. Water quality and hydraulic measurements were made at these rivers, with the intention of developing a numerical model. The model results showed deterioration in BOD5 and NH3-N in the Semangar River, up to 4.0 mg/dm 3 and 0.34 mg/dm 3 , respectively. The Beluntu River experienced the highest degradation, to about 14.0 mg/dm 3 of BOD5 and 0.8 mg/dm 3 of NH3-N. The waste assimilative capacity (WAC) for the Matang Besar, Che Minah and Beluntu Rivers were very limited, with a class III BOD5 limit of 15, 43, and 10 kg/day, respectively, whereas the Terumpah River is not able to accept any BOD load without breaching the same threshold.
Biohydrogen has been recognized to be one of the future renewable energy sources and has the pote... more Biohydrogen has been recognized to be one of the future renewable energy sources and has the potential in solving the greenhouse effects. In this study, Enterobacter aerogenes (E. aerogenes) was used as the biohydrogen producer via dark fermentation process using sago wastewater as the substrate. However, pretreatment of sago wastewater is required since it consists of complex sugars that cannot be utilized directly by the bacteria. This study aimed to use acid pretreatment method to produce high amount of glucose from sago wastewater. Three different types of acid: sulfuric acid (H2SO4); hydrochloric acid (HCl) and nitric acid (HNO3) were screened for the best acid in producing a maximum amount of glucose. H2SO4 gave the highest amount of glucose which was 9.406 g/L. Design of experiment was done using Face-centred Central Composite Design (FCCCD) tool under Response Surface Methodology (RSM) in Design Expert 9 software. The maximum glucose (9.138 g/L) was recorded using 1 M H2SO4 ...
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