Mohd Ali Hassan

The treatment of oil palm empty fruit bunch fibre for subsequent use as substrate for cellulase production by Chaetomium globosum Kunze

The feasibility of using treated oil palm empty fruit bunch (OPEFB) fibre as a substrate for cellulase production by Chaetomium globosum Kunze was studied using a shaking flask fermentation system. The use of 2-mm chemically untreated OPEFB fibre increased cellulase production by about two times compared to 10-mm fibre. The effect of the different chemicals (NaOH, HCl, HNO3, EDA and EDTA) on the 2-mm fibre was also investigated. Treatment with these chemicals significantly (P < 0·05) increased the cellulose and reduced the lignin contents. Fermentation using OPEFB fibre treated with HNO3(0·5% v/v) gave the highest cellulase production and this was related to its high cellulose content. Cellulase production increased further when autoclaved (121°C, 15 psi for 5 min), chemically treated OPEFB fibre was used. When autoclaved 2-mm OPEFB fibre treated with HNO3 was used as a substrate, the maximum FPase activity and yield obtained were 0·95 U ml−1 and 120·7 U g−1 cellulose, respectively. The cellulase produced by C. globosum contained a high proportion of β-glucosidase. The ratio of specific activity of β-glucosidase to FPase was about 8. The production of all three major components of cellulase (endoglucanase, cellobiohydrolase and β-glucosidase) using pretreated OPEFB fibre were about three times higher than those obtained in fermentations using pure cellulose (Avicel and carboxymethylcellulose).

Production of bacterial endoglucanase from pretreated oil palm empty fruit bunch by bacillus pumilus EB3

In this study, endoglucanase was produced from oil palm empty fruit bunch (OPEFB) by a locally isolated aerobic bacterium, Bacillus pumilus EB3. The effects of the fermentation parameters such as initial pH, temperature, and nitrogen source on the endoglucanase production were studied using carboxymethyl cellulose (CMC) as the carbon source. Endoglucanase from B. pumilus EB3 was maximally secreted at 37 degrees C, initial pH 7.0 with 10 g/l of CMC as carbon source, and 2 g/l of yeast extract as organic nitrogen source. The activity recorded during the fermentation was 0.076 U/ml. The productivity of the enzyme increased twofold when 2 g/l of yeast extract was used as the organic nitrogen supplement as compared to the non-supplemented medium. An interesting finding from this study is that pretreated OPEFB medium showed comparable results to CMC medium in terms of enzyme production with an activity of 0.063 U/ml. As OPEFB is an abundant solid waste at palm oil mills, it has the potential of acting as a substrate in cellulase production.

Effect of organic acid profiles during anaerobic treatment of palm oil mill effluent on the production of polyhydroxyalkanoates by Rhodobacter sphaeroides

A two-stage process for the production of polyhydroxy-alkanoates (PHA) from palm oil mill effuent (POME) is proposed. In the first stage, anaerobic treatment of POME by palm oil sludge was carried out to obtain organic acids, particularly acetic and propionic acids. The organic acids were then converted to PHA by a phototrophic bacterium, Rhodobacter sphaeroides (IFO 12203), in the second stage. During anaerobic treatment of POME by sludge, formic acid was formed when the pH was maintained at less than 4. By controlling the pH at different values, different organic acid profiles were obtained. This study was carried out to determine the effect of formic acid on the production of PHA from acetic and propionic acids by R. sphaeroides. The results clearly indicated that the presence of formic acid substantially decreased PHA yield (g·g−1-organic acid consumed) and PHA content in cells (g·g−1-cell weight). In the absence of formic acid, a PHA yield of 0.50 g·g−1 and a PHA content in cells of 67% were obtained. With increasing formic acid concentration, the PHA yield and content dropped to as low as 0.21 and 18%, respectively. Thus it is suggested that if POME is used for PHA production, a pH should be maintained at 7 in the anaerobic sludge treatment step, so that no formic acid is produced which would affect the maximum yield of PHA.

Optimization of growth media components for polyhydroxyalkanoate (PHA) production from organic acids by Ralstonia eutropha.

We employed systematic mixture analysis to determine optimal levels of acetate, propionate, and butyrate for cell growth and polyhydroxyalkanoate (PHA) production by Ralstonia eutropha H16. Butyrate was the preferred acid for robust cell growth and high PHA production. The 3-hydroxyvalerate content in the resulting PHA depended on the proportion of propionate initially present in the growth medium. The proportion of acetate dramatically affected the final pH of the growth medium. A model was constructed using our data that predicts the effects of these acids, individually and in combination, on cell dry weight (CDW), PHA content (%CDW), PHA production, 3HV in the polymer, and final culture pH. Cell growth and PHA production improved approximately 1.5-fold over initial conditions when the proportion of butyrate was increased. Optimization of the phosphate buffer content in medium containing higher amounts of butyrate improved cell growth and PHA production more than 4-fold. The validated organic acid mixture analysis model can be used to optimize R. eutropha culture conditions, in order to meet targets for PHA production and/or polymer HV content. By modifying the growth medium made from treated industrial waste, such as palm oil mill effluent, more PHA can be produced.

The production of polyhydroxyalkanoate from anaerobically treated palm oil mill effluent by Rhodobacter sphaeroides

Abstract Palm oil mill effluent (POME) was first subjected to anaerobic treatment for production of organic acids, particularly acetic and propionic acids, and later used for the production of polyhydroxyalkanoate (PHA) by a photosynthetic bacterium, Rhodobacter sphaeroides (IFO 12203). However, no PHA was produced by R. sphaeroides in the POME treated anaerobically which included sludge particles. On the other hand, after removal of the sludge, the PHA was continuously produced. At a dilution rate of 0.072 d−1, more than 1.0 g of PHA l−1 could be obtained from anaerobically treated POME containing 5.5 gl−1 of organic acids, corresponding to more than 30% of the dry cell weight. At a dilution rate of 0.024 d−1, more than 2 g of PHA l−1 could be obtained from POME containing 15 gl−1 of organic acids, corresponding to more than 60% of the dry cell weight.

Renewable sugars from oil palm frond juice as an alternative novel fermentation feedstock for value-added products.

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.

Enzyme production and profile by Aspergillus niger during solid substrate fermentation using palm kernel cake as substrate

The oil palm sector is one of the major plantation industries in Malaysia. Palm kernel cake is a byproduct of extracted palm kernel oil. Mostly palm kernel cake is wasted or is mixed with other nutrients and used as animal feed, especially for ruminant animals. Recently, palm kernel cake has been identified as an important ingredient for the formulation of animal feed, and it is also exported especially to Europe, South Korea, and Japan. It can barely be consumed by nonruminant (monogastric) animals owing to the high percentages of hemicellulose and cellulose contents. Palm kernel cake must undergo suitable pretreatment in order to decrease the percentage of hemicellulose and cellulose. One of the methods employed in this study is fermentation with microorganisms, particularly fungi, to partially degrade the hemicellulose and cellulose content. This work focused on the production of enzymes by Aspergillus niger and profiling using palm kernel cake as carbon source.

Modification of Oil Palm Mesocarp Fiber Characteristics Using Superheated Steam Treatment

In this study, oil palm mesocarp fiber (OPMF) was treated with superheated steam (SHS) in order to modify its characteristics for biocomposite applications. Treatment was conducted at temperatures 190–230 °C for 1, 2 and 3 h. SHS-treated OPMF was evaluated for its chemical composition, thermal stability, morphology and crystallinity. OPMF treated at 230 °C exhibited lower hemicellulose content (9%) compared to the untreated OPMF (33%). Improved thermal stability of OPMF was found after the SHS treatment. Moreover, SEM and ICP analyses of SHS-treated OPMF showed that silica bodies were removed from OPMF after the SHS treatment. XRD results exhibited that OPMF crystallinity increased after SHS treatment, indicating tougher fiber properties. Hemicellulose removal makes the fiber surface more hydrophobic, whereby silica removal increases the surface roughness of the fiber. Overall, the results obtained herewith suggested that SHS is an effective treatment method for surface modification and subsequently improving the characteristics of the natural fiber. Most importantly, the use of novel, eco-friendly SHS may contribute to the green and sustainable treatment for surface modification of natural fiber.

Production of cellulase by a wild strain of Chaetomium globosum using delignified oil palm empty-fruit-bunch fibre as substrate

Abstract Studies on the feasibility of using delignified oil palm empty-fruit-bunch (OPEFB) fibres as a substrate for cellulase production by Chaetomium globosum strain 414 were carried out in shake-flask cultures containing different types and concentrations of nitrogen source. Peptone, as nitrogen source, gave maximum production of all the three main components of the cellulase complex (endoglucanase or carboxymethylcellulase, cellobiohydrolase or filter-paper-hydrolysing enzyme and β-glucosidase), followed by yeast extract, urea, KNO3 and (NH4)2SO4. The maximum specific growth rate (μmax) of C. globosum strain 414 grown in medium containing OPEFB and peptone was 0.038 h−1. In all the fermentations, the fungus was able to produce all the three cellulases with significant amounts of β-glucosidase, except when using (NH4)2SO4 as nitrogen source, where β-glucosidase was not produced. With 6 g/l peptone and 10 g/l delignified OPEFB fibres, the fungus produced maximum concentrations of FPase, carboxymethylcellulase and β-glucosidase: 1.4, 30.8 and 9.8 U/ml, giving productivities of 10, 214 and 24 U l−1h−1, respectively. The cellulase mixture, partially purified by ammonium sulphate precipitation, was able to hydrolyse delignified OPEFB fibres, converting about 68 % of the cellulosics to reducing sugars after 5 days.

Influence of pretreated activated sludge for electricity generation in microbial fuel cell application.

Influence of different pretreated sludge for electricity generation in microbial fuel cells (MFCs) was investigated in this study. Pre-treatment has shown significant improvement in MFC electricity productivity especially from microwave treated sludge. Higher COD reduction in the MFC has been revealed from microwave treated sludge with 55% for total and 85% for soluble COD, respectively. Nonetheless, longer ozonation treatment did not give additional advantage compared to the raw sludge. On the other hand, samples from anodes were analyzed using the 16S rRNA gene-based pyrosequencing technique for microbial community analysis. There was substantial difference in community compositions among MFCs fed with different pretreated sludge. Bacteroidetes was the abundant bacterial phylum dominated in anodes of higher productivity MFCs. These results demonstrate that using waste sludge as the substrate in MFCs could achieve both sludge reduction and electricity generation, and proper pre-treatment of sludge could improve the overall process performance.