Influence of iron (II) oxide nanoparticle on biohydrogen production in thermophilic mixed fermentation

The effect of initial pH, metal oxide and concentration of nanoparticles (NP) on hydrogen production were investigated in batch assays using glucose-fed anaerobic mixed bacteria in thermophilic condition of 60 �C. Two type of metal oxide nanoparticles, iron (II) oxide and nickel oxide, were tested and both metal capable of increasing the hydrogen yield about 34.38% and 5.47% higher than the control test. The experiments on the effect of initial pH were done without adding the nanoparticles to determine the optimum pH for maximum hydrogen production, in which at pH 5.5, the maximum hydrogen yield has reached about 1.78 mol H2/mol glucose. However, at pH 5.5 and the optimal iron (II) oxide concentration of 50 mg/L, the maximum hydrogen yield has reached to 1.92 mol H2/mol glucose, and the hydrogen content was 51%. Furthermore, the analysis of metabolites has indicated that the hydrogen production follows the acetic acid pathway. In all experiments with metal oxide nanoparticles, the metal NP was not consumed by the microbes, and the amount of it at the end of the fermentation was similar to the starting amount, which can be concluded that it was acting as an enhancer to the system to improve the hydrogen production. These results suggest that the addition of iron (II) oxide nanoparticles in the system is the vital factor to enhance the hydrogen production

Kinetic Model of Thermophilic Biohydrogen Production from POME

The study of fermentation kinetic parameters are crucial to understanding the environmental factors affect on biohydrogen production. Kinetic models for hydrogen production from anaerobic digestion of palm oil mill effluent (POME) by mixed culture were developed based on published work. The models accounted for substrate limitation, substrate inhibition, hydrogen production, and endogenous decay rate. Data from previous literature were used to compare four microbial growth kinetic models for hydrogen production in an ASBR system. The estimated values of the maximum specific growth rate (μm) were found to be 0.371 h-1. In this study, the parameters of Y, kd, and B0 calculated were 2.64 gVSS/gCOD, 0.053 h-1, and 0.133 L H2/gCOD, respectively. The model fitting was found to be in good agreement with the experimental and can be utilized for the optimization and design of the process

Biohydrogen production in semicontinuous system using immobilized cell membrane

Hydrogen is considered to be the fuel of the future because of its high energy content (122 kJ/g), and water is the only byproduct of its use. Moreover, the production of hydrogen via fermentation of organic wastes is carbon neutral. This study was conducted to evaluate the performance of immobilized cells on PVDF membrane for biohydrogen production using a sequencing batch reactor by varying the hydraulic retention times (HRT) of the system and to compare the efficiency between suspended and attached systems on the production of biohydrogen. It was found that the biohydrogen fermentation performance was improved in a semi-continuous system, especially with immobilized cells. The optimum HRT that supports the highest biohydrogen yield was for an HRT of 12 hours, where the performance of hydrogen production was improved and in which the maximum hydrogen yield was achieved at 2.43 mol H2/mol and maximum hydrogen production rate (HPR) of 2.46 L H2/L.d as compared to other HRT for both systems. Therefore, the result of this study can be applied as the benchmark for scaling up the process

Expression of furfural reductase improved furfural tolerance in Antarctic bacterium pseudomonas extremaustralis

Whole-cell biocatalysis using Antarctic bacteria is presently hampered by a lack of genetic information, limited gene tools and critically, a poor range of cultivation conditions. In this work, biological engineering strategy was employed for developing Pseudomonas extremaustralis, a metabolically-versatile and biopolymer-producing Antarctic bacterium, as a new whole-cell biocatalytic host. For this purpose, gene cloning and plasmid construction were carried out for overexpression of furfural reductase (FucO), an industrially-important enzyme for degradation of toxic furfural compound commonly found in lignocellulosic biorefinery. FucO gene from Escherichia coli BL21 was cloned in pJM105 plasmid and transformed into competent cells of P. extremaustralis to generate a biologically-engineered pFucO strain. For functional characterization of the enzyme, furfural reductase activity was assayed, where the P. extremaustralis pFucO strain exhibited increased furfural reductase activity of about 15.6 U/mg, an 18.8-fold higher than empty plasmid-carrying control pJM105 strain (0.83 U/mg). Furfural detoxification activity using whole cells was also determined by which the overexpression of FucO led to increased tolerance and cell growth with an OD600 value of 5.3 as compared to the control pJM105 strain that was inhibited with 10 mM furfural during 48-hour cultivation. Therefore, the findings obtained in this study successfully demonstrated the development of P. extremaustralis as biocatalytic host for the production of recombinant furfural reductase. The bioengineering would serve as a modular biotechnological platform for polar strain and bioproduct development tailored towards industrial biotechnology applications

Oil palm biomass pretreatment and hydrolysis: a recent biotechnological venture towards bio-based lactic acid production

The effective utilisation of lignocellulosic biomass as fossil-based counterparts in the development of bio-based chemicals manufacturing is progressively relevant. Hence, many works are underway to shift from petrochemical industries to a sustainable lignocellulosic biomass biorefinery in lactic acid production. Malaysia is the leading country as a palm oil producer, with an enormous supply of inexpensive, renewable and non-food, yet untapped oil palm biomass resources. In this regard, oil palm fronds (OPF) rich in glucan content account for 60% of total agricultural biomass in Malaysia, which can accommodate 2 million metric tons per annum of fermentable sugar. The richness of carbohydrates in OPF serves as the key to unlocking bio-based lactic acid commercialization for future sustainable breakthroughs. This paper aims to provide insights into the exploitation of OPF as the novel feedstocks in bio-refinery processes. Special emphasis in this review is put on the technology, global demand, commercial status and future prospects of the production of second-generation lactic acid, as this process has received most research and development efforts so far. It reviews the current research attributed to the compositional analysis of OPF by primarily focusing on the National Renewable Energy Laboratories (NREL) protocol. It then focuses on the recent technological advancements of different pretreatment methods and hydrolysis for carbohydrate recovery in lactic acid production. Given with the tremendous potential, OPF can be exploited as an excellent sugar platform for the production of higher value products such as advanced biofuels, fine-platform chemicals and bioenergy

Synergistic enhancement of biohydrogen production by supplementing with green synthesized magnetic iron nanoparticles using thermophilic mixed bacteria culture

The production of biohydrogen can be improved by focusing on the nutrients needed by fermentative bacteria like iron. Iron reacts with the [Fe-Fe]-hydrogenase enzyme within the mixed bacteria culture for optimum hydrogen release. Iron nanoparticles (NPs) are attractive due to its unique properties and high reactivity. It can be produced through green synthesis, a more eco-friendly and relatively lower cost process, by using iron salt as precursor and green coconut shell extracted by deep eutectic solvent (DES) as reducing agent. The coconut shell extract consists of phytochemicals that help in producing poly�disperse magnetic iron oxide nanoparticles at ~75 nm in size. The addition of optimum concentration of 200 mg Fe/L magnetic iron NPs resulted in the maximum cumulative hydrogen production, glucose utilization and hydrogen yield of 101.33 mL, 9.12 g/L and 0.79 mol H2/mol glucose respectively. Furthermore, the kinetic analysis on Gompertz model using the optimum magnetic iron NPs concentration showed that the hydrogen production potential (P) and hydrogen production rate (Rm) increased to 50.69 mL and 3.30 mL/h respectively and the lag phase time reduced about 7.12 h as compared with the control experiment (0 mg Fe/L). These results indicated the positive effects of magnetic iron NPs supplementation on fermentative biohydrogen production of mixed bacteria culture and proved the feasibility of adding the magnetic iron NPs as the micronutrient for enhancement of such hydrogen production system

Biogas production under different inoculum to palm oil mill effluent ratio

Palm oil mill effluent (POME) is a wastewater generated from palm oil industries that rich with organic and nutrients which can becomes an excellent substrate for biogas production. A comprehensive study was carried out to study the effect of different ratio of inoculum to POME substrate for biogas production. In addition, the removal efficiencies of biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammoniacal nitrogen (AN), total nitrogen (TN) total suspended solid (TSS), volatile suspended solid (VSS) were also evaluated. Bio-methane potential (BMP) was used by manipulating temperature and HRT which were set to 28-32 °C and 30 days. The BMPs were operated under different ratio of inoculum to substrate at ratio of 20:80, 30:70 and 40:60. Highest cumulative biogas yield obtained was 1990 mL in the BMP containing 30:70 (inoculum:substrate) followed by the ratio of 40:60 with 1055 mL and 20:80 with 345 mL. Maximum TSS and VSS removal efficiency were 27% and 55%, recorded in 30:70 respectively, while in 40:60 and 20:80 were 23% and 12% and 8% and 51% respectively. The removal of TN was also high at 30:70 with 79% removal. Removal efficiency of COD was in BMP of 20:80 with 54% removal while BOD removal was seen the highest in 40:60 ratio BMP. Lastly, the AN were managed to be removed about 95% in 20:80 BMP. The results obtained in this study indicated that with different ratio od inoculum to POME substrate can enhance biogas production and quality of POME prior discharge to environment

Nanocellulose-Based Biomaterial Ink Hydrogel for Uptake/Release of Bovine Serum Albumin

This study explores the potential of using nanocellulose extracted from oil palm empty fruit bunch (OPEFB) as a biomaterial ink for 3D printing. The research focuses on using nanocellulose hydrogels for the controlled uptake and release of proteins, with the specific protein solution being Bovine Serum Albumin (BSA). To provide a suitable material for the bioprinting process, the study examines the characteristics and properties of the printed hydrogels through various analyses, such as morphology, functional group, crystallinity, and compression test. Several parameters, such as initial concentration, temperature, and the presence of calcium chloride as an additional crosslinker, affect the protein uptake and release capabilities of the hydrogel. The study is important for biomedicine as it explores the behavior of protein uptake and release using nanocellulose and 3D printing and can serve as a preliminary study for using hydrogels in biological materials or living cells

Isolation and characterization of biohydrogen-producing bacteria for biohydrogen fermentation using oil palm biomass-based carbon source

The effectiveness of biohydrogen conversion from biomass sources is governed by the selection of ideal biohydrogen-producing bacteria to achieve high and consistent production performance. The aim of this research was to isolate and identify a biohydrogen producer in local soil samples, as well as to evaluate its fermentability in biohydrogen production from oil palm empty fruit bunches (OPEFB). To this end, preliminary identification was performed using morphological, phenotype, biological, and 16s rRNA analyses. The fermentability of the isolate was further evaluated in a serum bottle and then in a 1.5 L anaerobic column bioreactor (ACBR) to investigate the potential for biohydrogen production using two OPEFB-based carbon sources: hydrolysate of ammonia fiber expansion (AFEX)-pretreated OPEFB and molasses from dilute acetic acid (DAA)-pretreated OPEFB. The isolated strain, Enterobacter sp. KBH 6958, was found to be capable of producing biohydrogen from various carbon sources via the pyruvate:ferredoxin oxidoreductase (PFOR) pathway. The cumulative conversion of AFEX OPEFB hydrolysate was 45% higher than that observed in DAA OPEFB molasses fermentation in the production of biohydrogen. The biohydrogen yield after fermenting AFEX OPEFB hydrolysate with Enterobacter sp. KBH 6958 was 1.55 mol H2/mol sugar, with a maximum productivity of 98.1 mL H2/h (4.01 mmol H2/L/h), whereas butyrate (10.6 mM), acetate (11.8 mM), and ethanol (4.56 mM) were found to be the major soluble metabolites. This study successfully demonstrated the biotechnological conversion of OPEFB into biohydrogen using a locally isolated strain, which not only solves environmental issues associated with the industry but may also offer a solution to the world’s energy insecurity

Strategi pengoptimuman lanjutan untuk meningkatkan penghasilan biohidrogen foto-fermentasi oleh bakteria ungu bukan sulfur

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 fotohidrogen 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-fermentasi oleh PNSB