Displaying publications 61 - 80 of 86 in total

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  1. Oil Palm Biomass Biorefinery for Sustainable Production of Renewable Materials
    Hassan MA, Ahmad Farid MA, Shirai Y, Ariffin H, Othman MR, Samsudin MH, et al.
    Biotechnol J, 2019 Jun;14(6):e1800394.
    PMID: 30925022 DOI: 10.1002/biot.201800394
    Oil palm biomass is widely known for its potential as a renewable resource for various value-added products due to its lignocellulosic content and availability. Oil palm biomass biorefinery is an industry that comes with sociopolitical benefits through job opportunities, as well as potential environmental benefits. Many studies have been conducted on the technological advancements of oil-palm biomass-derived renewable materials, which are discussed comprehensively in this review. Recent technological developments have made it possible to bring new and innovative technologies to commercialization, such as compost, biocharcoal, biocomposites, and bioplastics.
  2. Hydrothermal and wet disk milling pretreatment for high conversion of biosugars from oil palm mesocarp fiber
    Zakaria MR, Norrrahim MN, Hirata S, Hassan MA
    Bioresour Technol, 2015 Apr;181:263-9.
    PMID: 25659104 DOI: 10.1016/j.biortech.2015.01.072
    Eco-friendly pretreatment methods for lignocellulosic biomass are being developed as alternatives to chemical based methods. Superheated steam (SHS), hot compressed water (HCW) and wet disk milling (WDM) were used individually and with combination to partially remove hemicellulose and alter the lignin composition of recalcitrant structure of oil palm mesocarp fiber (OPMF). The efficiency of the pretreatment methods was evaluated based on the chemical compositions altered, SEM analysis, power consumption and degree of enzymatic digestibility. Hemicellulose removal (94.8%) was more pronounced under HCW compared to SHS, due to maximal contact of water and production of acetic acid which enhanced further degradation of hemicellulose. Subsequent treatment with WDM resulted in defibrillation of OPMF and expansion of the specific surface area thus increasing the conversion of cellulose to glucose. The highest glucose yield was 98.1% (g/g-substrate) when pretreated with HCW (200 °C, 20 min) and WDM which only consumed 9.6 MJ/kg of OPMF.
  3. Hydrothermal pretreatment enhanced enzymatic hydrolysis and glucose production from oil palm biomass
    Zakaria MR, Hirata S, Hassan MA
    Bioresour Technol, 2015 Jan;176:142-8.
    PMID: 25460995 DOI: 10.1016/j.biortech.2014.11.027
    The present works investigate hydrothermal pretreatment of oil palm empty fruit bunch and oil palm frond fiber in a batch tube reactor system with temperature and time range from 170 to 250°C and 10 to 20min, respectively. The behavior of soluble sugars, acids, furans, and phenols dramatically changed over treatment severities as determined by HPLC. The cellulose-rich treated solids were analyzed by SEM, WAXD, and BET surface area. Enzymatic hydrolysis was performed from both pretreated slurries and washed solid, and data obtained suggested that tannic acid derived from lignin degradation was a potential cellulase inhibitor. Both partial removal of hemicellulose and migration of lignin during hydrothermal pretreatment caused structural changes on the cellulose-hemicellulose-lignin matrix, resulting in the opening and expansion of specific surface area and pore volume. The current results provided important factors that maximize conversion of cellulose to glucose from oil palm biomass by hydrothermal process.
  4. Combined pretreatment using alkaline hydrothermal and ball milling to enhance enzymatic hydrolysis of oil palm mesocarp fiber
    Zakaria MR, Hirata S, Hassan MA
    Bioresour Technol, 2014 Oct;169:236-43.
    PMID: 25058299 DOI: 10.1016/j.biortech.2014.06.095
    Hydrothermal pretreatment of oil palm mesocarp fiber was conducted in tube reactor at treatment severity ranges of log Ro = 3.66-4.83 and partial removal of hemicellulose with migration of lignin was obtained. Concerning maximal recovery of glucose and xylose, 1.5% NaOH was impregnated in the system and subsequent ball milling treatment was employed to improve the conversion yield. The effects of combined hydrothermal and ball milling pretreatments were evaluated by chemical composition changes by using FT-IR, WAXD and morphological alterations by SEM. The successful of pretreatments were assessed by the degree of enzymatic digestibility of treated samples. The highest xylose and glucose yields obtained were 63.2% and 97.3% respectively at cellulase loadings of 10 FPU/g-substrate which is the highest conversion from OPMF ever reported.
  5. Indigenous cellulolytic and hemicellulolytic bacteria enhanced rapid co-composting of lignocellulose oil palm empty fruit bunch with palm oil mill effluent anaerobic sludge
    Zainudin MHM, Hassan MA, Tokura M, Shirai Y
    Bioresour Technol, 2013 Nov;147:632-635.
    PMID: 24012093 DOI: 10.1016/j.biortech.2013.08.061
    The composting of lignocellulosic oil palm empty fruit bunch (OPEFB) with continuous addition of palm oil mill (POME) anaerobic sludge which contained nutrients and indigenous microbes was studied. In comparison to the conventional OPEFB composting which took 60-90 days, the rapid composting in this study can be completed in 40 days with final C/N ratio of 12.4 and nitrogen (2.5%), phosphorus (1.4%), and potassium (2.8%), respectively. Twenty-seven cellulolytic bacterial strains of which 23 strains were closely related to Bacillus subtilis, Bacillus firmus, Thermobifida fusca, Thermomonospora spp., Cellulomonas sp., Ureibacillus thermosphaericus, Paenibacillus barengoltzii, Paenibacillus campinasensis, Geobacillus thermodenitrificans, Pseudoxanthomonas byssovorax which were known as lignocellulose degrading bacteria and commonly involved in lignocellulose degradation. Four isolated strains related to Exiguobacterium acetylicum and Rhizobium sp., with cellulolytic and hemicellulolytic activities. The rapid composting period achieved in this study can thus be attributed to the naturally occurring cellulolytic and hemicellulolytic strains identified.
  6. Renewable sugars from oil palm frond juice as an alternative novel fermentation feedstock for value-added products
    Zahari MA, Zakaria MR, Ariffin H, Mokhtar MN, Salihon J, Shirai Y, et al.
    Bioresour Technol, 2012 Apr;110:566-71.
    PMID: 22342083 DOI: 10.1016/j.biortech.2012.01.119
    In this paper, we report that pressed juice from oil palm frond (OPF) contained renewable sugars such as glucose, sucrose and fructose. By using a simple sugarcane press, 50% (wt/wt) of OPF juice was obtained from fresh OPF. The glucose content in the juice was 53.95±2.86g/l, which accounts for 70% of the total free sugars. We have examined the effect of various OPF juice concentrations on the production of poly(3-hydroxybutyrate), P(3HB) by Cupriavidus necator CCUG 52238(T). The cell dry mass in shake flask experiment reached 8.42g/l, with 32wt.% of P(3HB) at 30% (v/v) of OPF juice, comparable with using technical grade sugars. The biopolymer had a molecular mass, M(w) of 812kDa, with a low polydispersity index of 1.61. This result indicates that OPF juice can be used as an alternative renewable carbon source for P(3HB) production and has potential as a renewable carbon source.
  7. Cultivation of aerobic granular sludge for rubber wastewater treatment
    Rosman NH, Nor Anuar A, Othman I, Harun H, Sulong Abdul Razak MZ, Elias SH, et al.
    Bioresour Technol, 2013 Feb;129:620-3.
    PMID: 23317554 DOI: 10.1016/j.biortech.2012.12.113
    Aerobic granular sludge (AGS) was successfully cultivated at 27±1 °C and pH 7.0±1 during the treatment of rubber wastewater using a sequential batch reactor system mode with complete cycle time of 3 h. Results showed aerobic granular sludge had an excellent settling ability and exhibited exceptional performance in the organics and nutrients removal from rubber wastewater. Regular, dense and fast settling granule (average diameter, 1.5 mm; settling velocity, 33 m h(-1); and sludge volume index, 22.3 mL g(-1)) were developed in a single reactor. In addition, 96.5% COD removal efficiency was observed in the system at the end of the granulation period, while its ammonia and total nitrogen removal efficiencies were up to 94.7% and 89.4%, respectively. The study demonstrated the capabilities of AGS development in a single, high and slender column type-bioreactor for the treatment of rubber wastewater.
  8. Soluble inhibitors generated during hydrothermal pretreatment of oil palm mesocarp fiber suppressed the catalytic activity of Acremonium cellulase
    Zakaria MR, Hirata S, Fujimoto S, Ibrahim I, Hassan MA
    Bioresour Technol, 2016 Jan;200:541-7.
    PMID: 26524253 DOI: 10.1016/j.biortech.2015.10.075
    Oil palm mesocarp fiber was subjected to hydrothermal pretreatment under isothermal and non-isothermal conditions. The pretreated slurries were separated by filtration, pretreated liquids and solids were characterized. An enzymatic digestibility study was performed for both pretreated slurries and solids to understand the effect of soluble inhibitors generated during the pretreatment process. The highest glucose yield obtained from pretreated slurries was 70.1%, and gradually decreased with higher pretreatment severities. The highest glucose yield obtained in pretreated solids was 100%, after pretreatment at 210°C for 20min. In order to study the inhibitory effects of compounds generated during pretreatment with cellulase, technical grade solutions that mimic the pretreated liquid were prepared and their effect on Acremonium cellulase activity was monitored using Avicel. Xylo-oligomers and tannic acid were identified as powerful inhibitors of Acremonium cellulase, and the lowest hydrolysis rate of Avicel of 0.18g/g-glucose released/L/h was obtained from tannic acid.
  9. Combined pretreatment with hot compressed water and wet disk milling opened up oil palm biomass structure resulting in enhanced enzymatic digestibility
    Zakaria MR, Hirata S, Fujimoto S, Hassan MA
    Bioresour Technol, 2015 Oct;193:128-34.
    PMID: 26125612 DOI: 10.1016/j.biortech.2015.06.074
    Combined pretreatment with hot compressed water and wet disk milling was performed with the aim to reduce the natural recalcitrance of oil palm biomass by opening its structure and provide maximal access to cellulase attack. Oil palm empty fruit bunch and oil palm frond fiber were first hydrothermally pretreated at 150-190° C and 10-240 min. Further treatment with wet disk milling resulted in nanofibrillation of fiber which caused the loosening of the tight biomass structure, thus increasing the subsequent enzymatic conversion of cellulose to glucose. The effectiveness of the combined pretreatments was evaluated by chemical composition changes, power consumption, morphological alterations by SEM and the enzymatic digestibility of treated samples. At optimal pretreatment process, approximately 88.5% and 100.0% of total sugar yields were obtained from oil palm empty fruit bunch and oil palm frond fiber samples, which only consumed about 15.1 and 23.5 MJ/kg of biomass, respectively.
  10. Effect of oil palm biomass cellulosic content on nanopore structure and adsorption capacity of biochar
    Lawal AA, Hassan MA, Zakaria MR, Yusoff MZM, Norrrahim MNF, Mokhtar MN, et al.
    Bioresour Technol, 2021 Jul;332:125070.
    PMID: 33878542 DOI: 10.1016/j.biortech.2021.125070
    The influence of biomass cellulosic content on biochar nanopore structure and adsorption capacity in aqueous phase was scarcely reported. Commercial cellulose (100% cellulose), oil palm frond (39.5% cellulose), and palm kernel shell (20.5% cellulose) were pyrolyzed AT 630 °C, characterized and tested for the adsorption of iodine and organic contaminants. The external surface area and average pore size increased with cellulosic content, where commercial cellulose formed biochar with external surface area of 95.4 m2/g and average pore size of 4.1 nm. The biochar from commercial cellulose had the largest adsorption capacities: 371.40 mg/g for iodine, 86.7 mg/L for tannic acid, 17.89 mg/g for COD and 60.35 mg/g for colour, while biochar from palm kernel shell had the least adsorption capacities. The cellulosic content reflected the differences in biochar nanopore structure and adsorption capacities, signifying the suitability of highly cellulosic biomass for producing biochar to effectively treat wastewater.
  11. Production of acetoin from hydrothermally pretreated oil mesocarp fiber using metabolically engineered Escherichia coli in a bioreactor system
    Mohd Yusoff MZ, Akita H, Hassan MA, Fujimoto S, Yoshida M, Nakashima N, et al.
    Bioresour Technol, 2017 Dec;245(Pt A):1040-1048.
    PMID: 28946206 DOI: 10.1016/j.biortech.2017.08.131
    Acetoin is used in the biochemical, chemical and pharmaceutical industries. Several effective methods for acetoin production from petroleum-based substrates have been developed, but they all have an environmental impact and do not meet sustainability criteria. Here we describe a simple and efficient method for acetoin production from oil palm mesocarp fiber hydrolysate using engineered Escherichia coli. An optimization of culture conditions for acetoin production was carried out using reagent-grade chemicals. The final concentration reached 29.9gL(-1) with a theoretical yield of 79%. The optimal pretreatment conditions for preparing hydrolysate with higher sugar yields were then determined. When acetoin was produced using hydrolysate fortified with yeast extract, the theoretical yield reached 97% with an acetoin concentration of 15.5gL(-1). The acetoin productivity was 10-fold higher than that obtained using reagent-grade sugars. This approach makes use of a compromise strategy for effective utilization of oil palm biomass towards industrial application.
  12. Novel health monitoring method using an RGB camera
    Hassan MA, Malik AS, Fofi D, Saad N, Meriaudeau F
    Biomed Opt Express, 2017 Nov 01;8(11):4838-4854.
    PMID: 29188085 DOI: 10.1364/BOE.8.004838
    In this paper we present a novel health monitoring method by estimating the heart rate and respiratory rate using an RGB camera. The heart rate and the respiratory rate are estimated from the photoplethysmography (PPG) and the respiratory motion. The method mainly operates by using the green spectrum of the RGB camera to generate a multivariate PPG signal to perform multivariate de-noising on the video signal to extract the resultant PPG signal. A periodicity based voting scheme (PVS) was used to measure the heart rate and respiratory rate from the estimated PPG signal. We evaluated our proposed method with a state of the art heart rate measuring method for two scenarios using the MAHNOB-HCI database and a self collected naturalistic environment database. The methods were furthermore evaluated for various scenarios at naturalistic environments such as a motion variance session and a skin tone variance session. Our proposed method operated robustly during the experiments and outperformed the state of the art heart rate measuring methods by compensating the effects of the naturalistic environment.
  13. Fulltext Oil palm frond juice as future fermentation substrate: a feasibility study
    Maail CM, Ariffin H, Hassan MA, Shah UK, Shirai Y
    Biomed Res Int, 2014;2014:465270.
    PMID: 25057489 DOI: 10.1155/2014/465270
    Oil palm frond (OPF) juice is a potential industrial fermentation substrate as it has high sugars content and the OPF are readily available daily. However, maximum sugars yield and storage stability of the OPF juice are yet to be determined. This study was conducted to determine the effect of physical pretreatment and storage duration of OPF petiole on sugars yield. Storage stability of OPF juice at different storing conditions was also investigated. It was found that OPF petiole squeezed by hydraulic pressing machine gave the highest sugars recovery at almost 40 g/kg, accounting for a recovery yield of 88%. Storage of OPF petiole up to 72 hrs prior to squeezing reduced the free sugars by 11 g/kg. Concentrated OPF juice with 95% water removal had the best storage stability at both 4 and 30°C, when it was stored for 10 days. Moreover, concentrated OPF syrup prepared by thermal processing did not give any Maillard effect on microbial growth. Based on our results, OPF juice meets all the criteria as a good fermentation substrate as it is renewable, consistently available, and easy to be obtained, it does not inhibit microbial growth and product formation, and it contains no impurities.
  14. Fulltext Improved properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) produced by Comamonas sp. EB172 utilizing volatile fatty acids by regulating the nitrogen source
    Zakaria MR, Ariffin H, Abd-Aziz S, Hassan MA, Shirai Y
    Biomed Res Int, 2013;2013:237806.
    PMID: 24106698 DOI: 10.1155/2013/237806
    This study presents the effect of carbon to nitrogen ratio (C/N) (mol/mol) on the cell growth and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) accumulation by Comamonas sp. EB172 in 2 L fermenters using volatile fatty acids (VFA) as the carbon source. This VFA was supplemented with ammonium sulphate and yeast extract in the feeding solution to achieve C/N (mol/mol) 5, 15, 25, and 34.4, respectively. By extrapolating the C/N and the source of nitrogen, the properties of the polymers can be regulated. The number average molecular weight (M n ) of P(3HB-co-3HV) copolymer reached the highest at 838 × 10(3) Da with polydispersity index (PDI) value of 1.8, when the culture broth was supplemented with yeast extract (C/N 34.4). Tensile strength and Young's modulus of the copolymer containing 6-8 mol% 3HV were in the ranges of 13-14.4 MPa and 0.26-0.34 GPa, respectively, comparable to those of polyethylene (PE). Thus, Comamonas sp. EB172 has shown promising bacterial isolates producing polyhydroxyalkanoates from renewable carbon materials.
  15. Fulltext Recovery of glucose from residual starch of sago hampas for bioethanol production
    Awg-Adeni DS, Bujang KB, Hassan MA, Abd-Aziz S
    Biomed Res Int, 2013;2013:935852.
    PMID: 23509813 DOI: 10.1155/2013/935852
    Lower concentration of glucose was often obtained from enzymatic hydrolysis process of agricultural residue due to complexity of the biomass structure and properties. High substrate load feed into the hydrolysis system might solve this problem but has several other drawbacks such as low rate of reaction. In the present study, we have attempted to enhance glucose recovery from agricultural waste, namely, "sago hampas," through three cycles of enzymatic hydrolysis process. The substrate load at 7% (w/v) was seen to be suitable for the hydrolysis process with respect to the gelatinization reaction as well as sufficient mixture of the suspension for saccharification process. However, this study was focused on hydrolyzing starch of sago hampas, and thus to enhance concentration of glucose from 7% substrate load would be impossible. Thus, an alternative method termed as cycles I, II, and III which involved reusing the hydrolysate for subsequent enzymatic hydrolysis process was introduced. Greater improvement of glucose concentration (138.45 g/L) and better conversion yield (52.72%) were achieved with the completion of three cycles of hydrolysis. In comparison, cycle I and cycle II had glucose concentration of 27.79 g/L and 73.00 g/L, respectively. The glucose obtained was subsequently tested as substrate for bioethanol production using commercial baker's yeast. The fermentation process produced 40.30 g/L of ethanol after 16 h, which was equivalent to 93.29% of theoretical yield based on total glucose existing in fermentation media.
  16. Fulltext The potential of Olea europaea extracts to prevent TGFβ1-induced epithelial to mesenchymal transition in human nasal respiratory epithelial cells
    Razali RA, Nik Ahmad Eid NAH, Jayaraman T, Amir Hassan MA, Azlan NQ, Ismail NF, et al.
    BMC Complement Altern Med, 2018 Jun 26;18(1):197.
    PMID: 29940929 DOI: 10.1186/s12906-018-2250-5
    BACKGROUND: One of the molecular mechanisms involved in upper airway-related diseases is epithelial-to-mesenchymal transition (EMT). Olea europaea (OE) has anti-inflammatory properties and thus, great potential to prevent EMT. This study aimed to investigate the effect of OE on EMT in primary nasal human respiratory epithelial cells (RECs).

    METHODS: Respiratory epithelial cells were isolated and divided into four groups: control (untreated), treated with 0.05% OE (OE group), EMT induced with 5 ng/ml of transforming growth factor beta-1 (TGFβ1 group) and treated with 5 ng/ml TGFβ1 + 0.05% OE (TGFβ1 + OE group). The effects of OE treatment on growth kinetics, morphology and protein expression in RECs were evaluated. Immunocytochemistry analysis was performed to quantitate the total percentage of E-cadherin and vimentin expression from day 1 to day 3.

    RESULTS: There were no significant differences between untreated RECs and OE-treated RECs in terms of their morphology, growth kinetics and protein expression. Induction with TGFβ1 caused RECs to have an elongated spindle shape, a slower proliferation rate, a higher expression of vimentin and a lower expression of E-cadherin compared with the control. Cells in the TGFβ1 + OE group had similar epithelial shape to untreated group however it had no significant differences in their proliferation rate when compared to TGFβ1-induced RECs. Cells treated with TGFβ1 + OE showed significantly reduced expression of vimentin and increased expression of E-cadherin compared with the TGFβ1 group (P 

  17. Production of organic acids from kitchen wastes
    Loh CW, Fakhru'l-Razi A, Hassan MA, Karim MI
    Artif Cells Blood Substit Immobil Biotechnol, 1999 Sep-Nov;27(5-6):455-9.
    PMID: 10595448
    This study involves the production of short-chain organic acids from kitchen wastes as intermediates for the production of biodegradable plastics. Flasks, without mixing were used for the anaerobic conversion of the organic fraction of kitchen wastes into short-chain organic acids. The influence of pH, temperature and addition of sludge cake on the rate of organic acids production and yield were evaluated. Fermentations were carried out in an incubator at different temperatures controlled at 30 degrees C. 40 degrees C, 50 degrees C, 60 degrees C and uncontrolled at room temperature. The pH was also varied at pH 5, 6, 7, and uncontrolled pH. 1.0 M phosphate buffer was used for pH control, and 1.0 M HCl and 1.0 M NaOH were added when necessary. Sludge cake addition enhanced the rate of maximum acids production from 4 days to 1 day. The organic acids produced were maximum at pH 7 and 50 degrees C i.e., 39.84 g/l on the fourth day of fermentation with a yield of 0.87 g/g soluble COD consumed, and 0.84 g/g TVS. The main organic acid produced was lactic acid (65-85%), with small amounts of acetic (10-30%), propionic (5-10%), and butyric (5-20%) acids. The results of this study showed that kitchen wastes could be fermented to high concentration of organic acids, which could be used as substrates for the production of biodegradable plastics.
  18. Degumming of crude palm oil by membrane filtration
    Ong KK, Fakhru'l-Razi A, Baharin BS, Hassan MA
    Artif Cells Blood Substit Immobil Biotechnol, 1999 Sep-Nov;27(5-6):381-5.
    PMID: 10595436
    The application of membrane separation in palm oil refining process has potential for energy and cost savings. The conventional refining of crude palm oil results in loss of oil and a contaminated effluent. Degumming of crude palm oil by membrane technology is conducted in this study. The objective of this research is to study the feasibility of membrane filtration for the removal of phospholipids in the degumming of crude palm oil, including analyses of phosphorus content, carotene content free fatty acids (as palmitic acid), colour and volatile matter. A PCI membrane module was used which was equipped with polyethersulfone membranes having a molecular weight cut off of 9,000 (type ES209). In this study, phosphorus content was the most important parameter monitored. The membrane effectively removed phospholipids resulting in a permeate with a phosphorus content of less than 0.3 ppm The percentage removal of phosphorus was 96.4% and was considered as a good removal. Lovibond colour was reduced from 27R 50Y to 20R 30Y. The percentage removal of carotene was 15.8%. The removal of colour was considered good but the removal of carotene was considered insignificant by the membrane. Free fatty acids and volatile matter were not removed. Typical of membrane operations, the permeate flux decreased with time and must be improved in order to be adopted on an industrial scale. Membrane technology was found to have good potential in crude palm oil degumming. However, an appropriate method has to be developed to clean the membranes for reuse.
  19. Feasibility study on the utilization of rubber latex effluent for producing bacterial biopolymers
    Tang SN, Fakhru'l-Razi A, Hassan MA, Karim MI
    Artif Cells Blood Substit Immobil Biotechnol, 1999 Sep-Nov;27(5-6):411-6.
    PMID: 10595441
    Rubber latex effluent is a polluting source that has a high biochemical oxygen demand (BOD). It is estimated that about 100 million liters of effluent are discharged daily from rubber processing factories. Utilization of this effluent such as the use of a coupled system not only can reduce the cost of treatment but also yield a fermentation feedstock for the production of bioplastic. This study initially was carried out to increase the production of organic acids by anaerobic treatment of rubber latex effluent. It was found that through anaerobic treatment the concentration of organic acids did not increase. Consequently, separation of organic acids from rubber latex effluent by anion exchange resin was examined as a preliminary study of recovering acetic and propionic acids. However, the suspended solids (SS) content in the raw effluent was rather high which partially blocked the ion-exchange columns. Lime was used to remove the SS in the rubber latex effluent. After the lime precipitation process, organic acids were found to adsorb strongly onto the anion exchange resin. Less adsorption of organic acids onto the resin was observed before the lime precipitation. This was probably due to more sites being occupied by colloidal particles on the resin thus inhibiting the adsorption of organic acids. The initial concentration of organic acids in the raw effluent was 3.9 g/L. After ion exchange, the concentration of the organic acids increased to 27 g/L, which could be utilized for production of polyhydroxyalkanoates (PHA). For PHA accumulation stage, concentrated rubber latex effluent obtained from ion exchange resins and synthetic acetic acid were used as the carbon source. Quantitative analyses from fed batch culture via HPLC showed that the accumulation of PHA in Alcaligenes eutrophus was maximum with a concentration of 1.182 g/L when cultivated on synthetic acetic acid, corresponding to a yield of 87% based on its cell dry weight. The dry cell weight increased from 0.71 to 1.67 g/L. On the other hand, using concentrated rubber latex effluent containing acetic and propionic acids resulted in reduced PHA content by dry weight (14%) but the dry cell weight increased from 0.49 to 1.30 g/L. The results clearly indicated that the cells grow well in rubber latex effluent but no PHA was accumulated. This could be due to the high concentration of propionic acid in culture broth or other factors such as heavy metals. Thus further work is required before rubber latex effluent can be utilized as a substrate for PHA production industrially.
  20. Effect of physical and chemical properties of oil palm empty fruit bunch, decanter cake and sago pith residue on cellulases production by Trichoderma asperellum UPM1 and Aspergillus fumigatus UPM2
    Zanirun Z, Bahrin EK, Lai-Yee P, Hassan MA, Abd-Aziz S
    Appl Biochem Biotechnol, 2014 Jan;172(1):423-35.
    PMID: 24085387 DOI: 10.1007/s12010-013-0530-6
    The effect of cultivation condition of two locally isolated ascomycetes strains namely Trichoderma asperellum UPM1 and Aspergillus fumigatus UPM2 were compared in submerged and solid state fermentation. Physical evaluation on water absorption index, solubility index and chemical properties of lignin, hemicellulose and cellulose content as well as the cellulose structure on crystallinity and amorphous region of treated oil palm empty fruit bunch (OPEFB) (resulted in partial removal of lignin), sago pith residues (SPR) and oil palm decanter cake towards cellulases production were determined. Submerged fermentation shows significant cellulases production for both strains in all types of substrates. Crystallinity of cellulose and its chemical composition mainly holocellulose components was found to significantly affect the total cellulase synthesis in submerged fermentation as the higher crystallinity index, and holocellulose composition will increase cellulase production. Treated OPEFB apparently induced the total cellulases from T. asperellum UPM1 and A. fumigatus UPM2 with 0.66 U/mg FPase, 53.79 U/mg CMCase, 0.92 U/mg β-glucosidase and 0.67 U/mg FPase, 47.56 U/mg and 0.14 U/mg β-glucosidase, respectively. Physical properties of water absorption and solubility for OPEFB and SPR also had shown significant correlation on the cellulases production.
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