Publications by authors named "Wan Mohtar Wan Yusoff"

A new isolate of the solvent-producing YM1 was used to produce butanol in batch culture fermentation. The effects of glucose concentration, butyric acid addition and C/N ratio were studied conventionally (one-factor-at-a-time). Moreover, the interactions between glucose concentration, butyric acid addition and C/N ratio were further investigated to optimize butanol production using response surface methodology (RSM).

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The effect of pH and butyric acid supplementation on the production of butanol by a new local isolate of YM1 during batch culture fermentation was investigated. The results showed that pH had a significant effect on bacterial growth and butanol yield and productivity. The optimal initial pH that maximized butanol production was pH 6.

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The role of lactic acid bacteria (LAB) in honey as antifungal activity has received little attention and their mechanism of inhibitory of fungi is not fully understood. In this study, LAB were isolated from honey samples from Malaysia, Libya, Saudi Arabia, and Yemen. Twenty-five isolates were confirmed LAB by catalase test and Gram staining, and were screened for antifungal activity.

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Improvement in the butanol production selectivity or enhanced butanol:acetone ratio (B:A) is desirable in acetone-butanol-ethanol (ABE) fermentation by Clostridium strains. In this study, artificial electron carriers were added to the fermentation medium of a new isolate of Clostridium acetobutylicum YM1 in order to improve the butanol yield and B:A ratio. The results revealed that medium supplementation with electron carriers changed the metabolism flux of electron and carbon in ABE fermentation by YM1.

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The locally isolated filamentous fungus Cunninghamella bainieri 2A1 was cultivated in a 5 L bioreactor to produce lipid and gamma-linolenic acid (GLA). The optimization was carried out using response surface methodology based on a central composite design. A statistical model, second-order polynomial model, was adjusted to the experimental data to evaluate the effect of key operating variables, including aeration rate and agitation speed on lipid production.

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Background: Trichoderma sp. SL2 has been previously reported to enhance rice germination, vigour, growth and physiological characteristics. The use of Potato Dextrose Agar as carrier of Trichoderma sp.

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The biosynthesis of biomedical products including lipid and gamma-linolenic acid (GLA) by Cunninghamella bainieri 2A1 was studied in repeated batch fermentation. Three key process variables, namely, glucose concentration, ammonium tartrate concentration, and harvesting time, were optimized using response surface methodology. Repeated batch fermentation was carried out by the cultivation of Cunninghamella bainieri 2A1 in nitrogen-limited medium with various nitrogen concentration (1-4 g/L) and glucose concentration (20-40 g/L) at three time intervals (12 h, 24 h, and 48 h).

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Trichoderma spp., a known beneficial fungus is reported to have several mechanisms to enhance plant growth. In this study, the effectiveness of seven isolates of Trichoderma spp.

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The production of biobutanol was studied by the cultivation of Clostridium acetobutylicum NCIMB 13557 in P2 medium including date fruit as the sole substrate. The effect of P2 medium and the effect of different concentrations of date fruit ranging from 10 to 100 g/L on biobutanol production were investigated. Anaerobic batch culture was carried out at 35 °C incubation temperature and pH 7.

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Date fruit juice contains high concentration of simple sugars ranging from 65 to 75% (w/w) in dry form. In this study, the potential of date fruit juice as biobutanol fermentation medium by C. acetobutylicum was investigated.

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Microbial mannanases have become biotechnologically important in industry but their application is limited due to high production cost. In presents study, the extraction of mannanase from fermented Palm Kernel Cake (PKC) in the Solid State Fermentation (SSF) was optimized. Local isolate of Aspergillus terreus SUK-1 was grown on PKC in (SSF) using column bioreactor.

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Rice bran (RB) and de-oiled rice bran (DRB) have been treated and used as the carbon source in acetone-butanol-ethanol (ABE) production using Clostridium saccharoperbutylacetonicum N1-4. The results showed that pretreated DRB produced more ABE than pretreated RB. Dilute sulfuric acid was the most suitable treatment method among the various pretreatment methods that were applied.

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Lipid biosynthesis and fatty acids composition of oleaginous zygomycetes, namely Cunninghamella bainieri 2A1, cultured in media with excess or limited nitrogen were quantitatively determined at different times of culture growth. Accumulation of lipids occurred even when the activity of NAD(+)-ICDH (β-Nicotinamide adenine dinucleotide-isocitrate dehydrogenase) was still detectable in both media. In C.

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The production of beta-mannanase from palm kernel cake (PKC) as a substrate in solid substrate fermentation (SSF) was studied using a laboratory column bioreactor. The simultaneous effects of three independent variables, namely incubation temperature, initial moisture content of substrate and airflow rate, on beta-mannanase production were evaluated by response surface methodology (RSM) on the basis of a central composite face-centered (CCF) design. Eighteen trials were conducted in which Aspergillus niger FTCC 5003 was cultivated on PKC in an aerated column bioreactor for seven days under SSF process.

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The bioremediation of polluted groundwater, wastewater aeration pond and biopond sites was investigated using bacteria isolated from these sites located at the oil refinery Terengganu Malaysia. Out of 62 isolates, only 16 isolates from groundwater (8) and wastewater aeration pond (3) and biopond (5) were chosen based on growth medium containing 1% (v/v) Tapis crude oil. Only four isolates; Acinetobacter faecalis, Staphylococcus sp.

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