Bioproduction of 1,3-propanediol (1,3-PDO) is regarded as a low carbon footprint bioprocess with ... more Bioproduction of 1,3-propanediol (1,3-PDO) is regarded as a low carbon footprint bioprocess with a 33% reduction of greenhouse gas (GHG) emissions compared to conventional chemical processes. In line with Sustainable Development Goal (SDG) 12, bioproduction of 1,3-PDO closes the loop between biodiesel waste glycerol and biobased 1,3-PDO to establish a circular bioeconomy. There are limited studies on the bioconversion of biodiesel-derived glycerol into 1,3-PDO via the immobilized cell biocatalysis route. In this study, the production of 1,3-PDO was enhanced by the wild-type Clostridium butyricum JKT 37 immobilized on the activated carbon of coconut shell (CSAC) as supporting material using the acidicpretreated glycerol as a carbon source. Among various mesh sizes of CSAC tested, the 6-12 mesh immobilizer had enhanced cell density by about 94.43% compared to the suspended cell system. Following the acidic pretreatment in 37% (v/v) HCl, the pretreated glycerol had 85.60% glycerol with complete removal of soaps. The immobilized cell fermentation using pretreated glycerol produced 8.04 ± 0.34 g/L 1,3-PDO with 0.62 ± 0.02 mol/mol of yield, 15.81% and 27.78% higher than the control, respectively. Five repeated batches of immobilized cell fermentation had resulted in the average 1,3-PDO titer, yield, and productivity of 16.40 ± 0.58 g/L, 0.60 ± 0.03 mol/mol, and 0.68 ± 0.02 g/L.h, respectively. The metabolism pathway gradually shifted to a reductive branch when immobilized cells were reused in repeated batch fermentation, proven by the reduction in organic acid formation and the increased ratio of 1,3-PDO-to-total organic acids.
International Journal of Biomass Utilization and Sustainable Energy (IJBUSE), Jul 17, 2023
White-rot fungus are known as natural source of antioxidant compounds such as flavonoids, phenoli... more White-rot fungus are known as natural source of antioxidant compounds such as flavonoids, phenolic, and other enzymes through extraction processes. In this study, Phanerochaete chrysosporium and Panus tigrinus biomass were subjected into different extraction conditions to determine the best optimal level for the extraction of phenolic and flavonoids compounds. P. chrysosporium produced high yield of phenolic (0.7041 mg/mL) and flavonoids (0.0286 mg/mL) compared to P. tigrinus; 0.3755 mg/mL and 0.0109 mg/mL of phenolic and flavonoids compounds, respectively. P. chrysosporium has higher antioxidant activity (70.31%) compared with P. tigrinus (25.30%). Therefore, P. chrysosporium was selected to determine the optimum condition for extraction method of phenolic and flavonoids compounds using aquoues-two phase system. The conditions used in the extraction was time within the range of 30 min to 180 min and temperature range from 250°C to 650°C. The conditions were optimized using Response Surface Method (RSM) under Central Composite Design. The best optimum condition was 105 min and 450°C, this condition produced the highest concentrations of phenolic, flavonoids, and antioxidant activity (AA%) at 0.4269 mg/mL, 0.0695 mg/mL, and 76.13% respectively. Thin Layer Chromatography (TLC) was used to determine the presence of phenolic and flavonoids in the sample. The Rf value from P. chrysosporium was 0.98 closed to the Rf values of gallic acid and 3,4-hydroxybenzoic acid at 0.95 and 0.97, respectively. Fourier Transform Infrared (FTIR) spectroscopy shows that P. chrysosporium have gallic acid, 3,4 hydroxybenzoic acid and small amount of quercetin.
International Journal of Hydrogen Energy, Nov 1, 2017
The availability of fermentable sugars in POME is one of the critical factors that determine the ... more The availability of fermentable sugars in POME is one of the critical factors that determine the fermentative biohydrogen production yield. This study was carried out to determine the pretreatment conditions viz., temperature, hydrolysis time and acid concentration that can yield the highest monomeric sugars, to be utilized for production of biohydrogen from POME by mixed culture dark fermentation. Two different acids were used, nitric acid and phosphoric acid in the pretreatment of POME. Batch fermentation was performed to determine the potential of pretreated POME as a substrate for the production of biohydrogen under the tested pretreatment conditions. Higher hydrogen yield was successfully achieved using pretreated POME as compared to raw POME by mixed culture. Maximum hydrogen production was 0.181 (mmol/L/h), which corresponded to the yield of 1.24 mol H 2 /mol glucose achieved at 0.8% (w/v) phosphoric acid with initial total reducing sugar concentration of 18.47 g/L. Hence, the results implied that POME pretreated with 0.8% (w/v) phosphoric acid is a potential substrate for efficient biohydrogen fermentation yield that is 97% higher than untreated POME. While POME pretreated with 1% (w/v) of nitric acid showed 65% improvement in biohydrogen yield as compared to untreated POME. Therefore, the results implied that both pretreatment methods of POME showed significant increase in the biohydrogen production.
Proses foto-fermentasi ialah suatu laluan penghasilan hidrogen yang menarik. Walau bagaimanapun, ... more Proses foto-fermentasi ialah suatu laluan penghasilan hidrogen yang menarik. Walau bagaimanapun, didapati bahawa kecekapan penukaran cahaya dan penghasilan biohidrogen foto-fermentasi oleh bakteria ungu bukan sulfur (PNSB) adalah sangat rendah. Maka, pelbagai pendekatan pengoptimuman telah dikaji bagi meningkatkan penghasilan foto-hidrogen dan prestasi keseluruhannya. Ulasan ini membincangkan strategi pengoptimuman lanjutan untuk meningkatkan penghasilan biohidrogen foto-fermentasi secara menyeluruh. Antara strategi yang dibincangkan merangkumi pengoptimuman makronutrien dalam media penghasilan biohidrogen, faktor abiotik dan rejim pencahayaan semasa proses foto-fermentasi berlaku. Pendekatan ini menunjukkan keputusan positif dalam meningkatkan penghasilan foto-hidrogen oleh PNSB. Pendekatan gabungan yang mengintegrasikan strategi pengoptimuman individu yang berbeza dipercayai mungkin dapat mendatangkan peningkatan yang sinergistik terhadap produktiviti dan hasil biohidrogen foto-fe...
This work aimed to comprehensively examine the pretreatment efficiency of oil palm empty fruit bu... more This work aimed to comprehensively examine the pretreatment efficiency of oil palm empty fruit bunches (EFB) using two different types of deep eutectic solvent (DES) mixtures, i.e., choline chloride/imidazole (DES-I) and choline chloride/glycerol (DES-G) in terms of pretreated EFB structural composition and enzymatic hydrolysis. The influence of the pretreatment temperature (55 °C, 90 °C, 125 °C, 160 °C, and 195 °C), EFB to solvent ratio (1:5, 1:10, 1:15, and 1:20), and pretreatment time (2 h, 4 h, and 6 h) on the performance of pretreated EFB and the generated black liquor was examined. The optimal conditions for EFB pretreatment were 160 °C, 1:5 ratio, and 2 h using DES-I solvent, and 160 °C, 1:10 ratio and 4 h using DES-G solvent. The structural carbohydrates of empty fruit bunch pretreated with DES-I, DES-I EFB1 and DES-G, DES-G EFB2 increased to 66.1%, and 64.6%, respectively. The enzymatic hydrolysis of DES-I EFB1 resulted in higher glucan conversion (92.4%) compared to DES-G ...
Production of cross-linked enzyme aggregate-lipase from channel catfish (ictularus punctatus) viscera
Cross linked enzyme aggregates technology is one of the latest methods in immobilization of enzym... more Cross linked enzyme aggregates technology is one of the latest methods in immobilization of enzymes. This technique provides biocatalysts with higher activity, stability and reusability in industrial applications. In this research, lipase was extracted from the viscera of river channel catfish (Ictularus punctatus) and was immobilized based on cross-liked enzyme aggregate methodology. Glutaraldehyde was used as a cross-linker, acetone as precipitant and bovine serum albumin as an additive to improve the formation of CLEA-lipase. Experimental design was carried out by Response Surface Methodology using central composite design to find the optimum conditions for immobilization which was 50 mM of glutaraldehyde, 60% (v/v) Acetone and 0.11 mM of BSA. Finally, CLEA-lipase’s specific activity was 1.713 U/mg that is 20.43% higher than the free lipase activity.
Techno-economic analysis of two-stage anaerobic system for biohydrogen and biomethane production from palm oil mill effluent
Journal of Environmental Chemical Engineering, 2021
Abstract The proliferation of biobased-renewable fuel industries was driven by the depletion of t... more Abstract The proliferation of biobased-renewable fuel industries was driven by the depletion of the finite fossil fuel reserves and the rising consciousness on sustainable and environmental consequences. Hence, the present study aims to establish baseline economics for a two-stage anaerobic system by performing a comprehensive analysis using a set of assumptions for what can plausibly be achieved within a twenty-year timeframe. The techno-economic analysis was carried out to elucidate the viability of the proposed anaerobic system that produces biohydrogen (BioH2), and biomethane (BioCH4) from locally generated palm oil mill effluent (POME). Process modelling and economic analysis were performed using a modelling software SuperPro Designer. The plant conditions were temperature at 50 °C for both stages, and HRT of 1 and 10 days for BioH2 and BioCH4, respectively. The economic profitability assessment demonstrated the feasibility of the project with the dynamic payback period (DPP), return on investment (ROI), internal rate of return (IRR), and net present value (NPV) of 8.01 years, 19.87%, 21.48% and USD 4624,705, respectively. Furthermore, the economics of this system was most sensitive to POME quality and product selling prices. The results revealed that a two-stage anaerobic system might both expand the production of renewable energy and enable improved productivity and revenue of palm oil mills to move forward cleaner production industry.
Optimization of Chlorella biomass harvesting by flocculation and its potential for biofuel production
Journal of Applied Phycology, 2021
Optimization of microalgal biomass harvesting is essential to produce effective and optimum outco... more Optimization of microalgal biomass harvesting is essential to produce effective and optimum outcomes that can contribute towards a feasible and economical harvesting technique. Two Chlorella species were used, namely, C. vulgaris and C. sorokiniana UKM3. Two essential factors affecting microalgal biomass harvesting via flocculation, namely, the initial pH of the microalgal broth and flocculant (chitosan) concentration were studied. The optimization process was conducted by using a response surface methodology (RSM) based on the model of face-centered-central composite design (FC-CCD). The potential for biofuel application of the harvested biomass was evaluated based on the production of fatty acid methyl esters (FAMEs) by transesterification. The quadratic models obtained from the RSM significantly fitted the experiment data as the p-values were less than 0.05. The initial pH of the microalgal suspension was found to have a more significant effect on the flocculation process than flocculant concentration. For C. vulgaris, the highest flocculant efficiency of 98.7% was obtained at a chitosan concentration of 0.2 g L−1 and an initial pH of 12.0, whereas for C. sorokiniana UKM3, at 0.15 g L−1 of chitosan and initial pH of 12.0 produced the highest efficiency of 97.1%. The harvested biomass of both species exhibited a high content of palmitic acid (C16:0) with 29.74 wt% and 11.81 wt% of dry biomass for C. vulgaris and C. sorokiniana UKM3, respectively. This study showed that Chlorella species can be harvested efficiently using the flocculation process and manifested an excellent potential for biodiesel production where palmitic acid (C16:0) is one of the main compounds for high-acid oil-biodiesel.
Enhancement of biohydrogen production from palm oil mill effluent (POME): A review
International Journal of Hydrogen Energy, 2021
Abstract Palm oil mill effluent (POME), a wastewater from the most significant agricultural indus... more Abstract Palm oil mill effluent (POME), a wastewater from the most significant agricultural industry in Southeast Asia is produced in tremendous amounts that requires proper management to mitigate its negative environmental effects. The feasibility of treating POME in a closed dark fermentation (DF) system to replace the existing inefficient open ponding treatment has been thoroughly investigated. Theoretically, the maximum H2 yield obtained by DF process is 4 molH2/molglucose, however, it is not achievable due to the nature of POME. In this study, several enhancement methods for increasing H2 yield and DF process stability were discussed. An apprehension into the different pre-treatment methods on POME including physicochemical, chemical and biological and their effects on the characteristics of POME including pH, temperature, sugar content, solid content, viscosity, nutrients and by-product toxicity on the biohydrogen production and effluent quality were reviewed. Various bioreactor designs were used for biohydrogen from POME, the modifications applied on the system design to increase the stability and productivity of POME treatment have been examined. Moreover, higher biohydrogen productivity could be obtained with the addition of nanoparticle nutrients and introducing genetically modified H2-producing bacteria. Finally, further investigation in the future shall focus on the development of a more inclusive and efficient POME treatment via DF process that favours biohydrogen production, environmental benign and economically viable.
This study compared the performance of thermophilic and mesophilic digesters of an anaerobic dige... more This study compared the performance of thermophilic and mesophilic digesters of an anaerobic digestion system from palm oil mill effluent (POME), in which temperature is a key parameter that can greatly affect the performance of anaerobic digestion. The digesters were incubated at two distinct temperatures of 55 and 37 °C, and operated with varying organic loading rates (OLRs) of 2.4, 3.2, and 4.0 g COD/L.d by altering the chemical oxygen demand (COD) of acidified POME during feeding. The results indicated that the performance of anaerobic digestion increased as the OLR increased from 2.4 to 4.0 g COD/L.d. At the OLR of 4.0 g COD/L.d, the thermophilic condition showed the highest methane yield of 0.31 ± 0.01 L/g COD, accompanied by the highest COD removal and volatile solid reduction, which were found to be higher than the mesophilic condition. Microbial community analysis via denaturing gradient gel electrophoresis (DGGE) revealed that Methanothermobacter sp. emerges as the dominan...
Various biotechnological approaches applied on photo-fermentation are reviewed. H 2 yield improve... more Various biotechnological approaches applied on photo-fermentation are reviewed. H 2 yield improved by optimisation on medium, abiotic factors and lighting regime. Novel photoluminating nanomaterials is promising to increase H 2 yield. Additional H 2 enhancement strategies are recommended for further research.
This study aimed to enhance the crystallizability of bio-based succinic acid for its efficient re... more This study aimed to enhance the crystallizability of bio-based succinic acid for its efficient recovery while maintaining the end product at the highest purity. Immobilization of Actinobacillus succinogenes was initially evaluated based on three different carriers: volcanic glass, clay pebbles, and silica particles. The adsorption capacity of metabolites with a low concentration (10 g/L) and a high concentration (40 g/L) was investigated. It was demonstrated that clay pebbles adsorbed the least succinic acid (< 11 mg/g clay pebbles). The repeated batch-fermentation trials with immobilized cells highlighted that succinic acid with an average concentration of up to 36.3 g/L with a metabolite-production ratio of 3:1 (succinic acid to by-products) could be attained within 130 h. Subsequently, the purification of succinic acid through crystallization was assessed in terms of pH, temperature, crystallization time, initial succinic acid concentration and multiple recrystallization processes. Increasing the crystallization time from 6 h to 9 h afforded an improvement of 17% in the recovery of succinic acid crystals. Moreover, a fourfold concentration coefficient of the broth yielded the highest purity percentage (99.9%). The crystallization in three consecutive stages at 9 h (with a fourfold concentration coefficient) successfully improved the total recovery percentage of succinic acid from 55.0 to 84.8%.
Effect of carbon/nitrogen ratio and ferric ion on the production of biohydrogen from palm oil mil... more Effect of carbon/nitrogen ratio and ferric ion on the production of biohydrogen from palm oil mill effluent (POME),
Palm oil mill effluent (POME), an agro-industrial wastewater with high solids content, was subjec... more Palm oil mill effluent (POME), an agro-industrial wastewater with high solids content, was subject to hydrolysis by 1% (w/v) nitric acid in order to increase its solubility and the fermentable sugar content from its cellulosic component. POME hydrolysate was then evaluated in an up-flow anaerobic sludge blanket (UASB) bioreactor for the production of biohydrogen gas via mixed culture under thermophilic conditions. The bioreactor was fed with pre-treated POME under varied hydraulic retention time (HRT) between 48-3 h at constant cycle length of 24 h to test the productivity of H 2 and the stability of UASB; no washout of biomass occurred at any cycle and the system managed to recover its H 2 production rate (HPR) after initial fluctuations. In this study, H 2 -producing granules (HPGs) were formed shortly after the start-up period, and were analysed by FESEM, FTIR, SEM-EDX, and their extracellular polymeric substances (EPS) content. The maximum HY and HPR achieved were 2.45 mol-H 2 /mol-sugar and 11.75 L H2 /L POME d -1 , respectively, at HRT 6 h. Acetic acid was found to be the major by-product at all HRTs, followed by butyric acid, while Clostridium spp. was found to be the most dominant H 2 -producing bacteria in the system. Results suggest that UASB has a good potential for stable H 2 production with high POME digestion rate.
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