Zahangir Alam

Optimization of process parameters for the bioconversion of activated sludge by Penicillium corylophilum, using response surface methodology

The optimization of process parameters for the bioconversion of activated sludge by Penicillium corylophilum was investigated using response surface methodology (RSM). The three parameters namely temperature of 33 degrees C, agitation of 150 r/min, and pH of 5 were chosen as center point from the previous study of fungal treatment. The experimental data on chemical oxygen demand (COD) removal (%) were fitted into a quadratic polynomial model using multiple regression analysis. The optimum process conditions were determined by analyzing response surface three-dimensional surface plot and contour plot and by solving the regression model equation with Design Expert software. Box-Behnken design technique under RSM was used to optimize their interactions, which showed that an incubation temperature of 32.5 degrees C, agitation of 105 r/min, and pH of 5.5 were the best conditions. Under these conditions, the maximum predicted yield of COD removal was 98.43%. These optimum conditions were used to evaluate the trail experiment, and the maximum yield of COD removal was recorded as 98.5%.

Enzymatic Hydrolysis of Plants and Algae for Extraction of Bioactive Compounds

Plants and algae contain novel biocompounds with therapeutic potentials. These compounds are either embedded within the cell wall matrix or bonded with polymers at cell cytoplasm, which hinders release of bioactive compounds during extraction. Enzymatic hydrolysis of cell wall and cytoplasm polymers enhances the release of biocompounds while preserving their biological potencies. Previous works have focused more on comparative studies of different enzymes, whereas other process parameters, such as agitation speed, substrate particle sizes, hydrolysis time, degree of hydrolysis, and multistage extraction, have received less attention. This review examines the extent of studies in this area and highlight current research gaps to be explored in future researches.

Enzymatic biodiesel production from sludge palm oil (SPO) using locally produced Candida cylindracea lipase

Biodiesel is a non-toxic, renewable and environmental friendly fuel. This study involved the production of biodiesel from sludge palm oil (SPO), a low-cost waste oil via enzymatic catalysis. The enzyme catalyst was a Candida cylindracea lipase, locally-produced using palm oil mill effluent as the low cost based medium. The results in solvent system for biodiesel production showed that ethanol gave higher yield of biodiesel as compared to methanol. One-factor-at-a time (OFAT) method was applied to investigate several factors for enzymatic biodiesel production. The optimum levels of ethanol-to-SPO molar ratio, enzyme loading, reaction temperature, mixing speed and reaction time were 4:1, 10 U, 40°C, 250 rpm and 24 h, respectively with maximum yield of biodiesel of 62.3% (w/w SPO). The SPO had a promising potential for enzymatic biodiesel production using locally-produced lipase.

Evaluation of nutritional components by Plackett- Burman design for Penicillium citrinum lipase production using palm oil mill effluent

A number of medium components influencing lipase production by Penicillium citrinum (ATCC 42799) were studied using palm oil mill effluent (POME) as the basal medium. The medium components (peptone, yeast extract, malt extract, NH4Cl, NaNO3, KH2PO4, CaCl2, MgSO4, olive oil and Tween-80) were analyzed in twelve experimental trials using Plackett‐Burman (PB) design. The most significant components affecting lipase production were found to be Tween-80, peptone, yeast extract, malt extract and NaNO3 at p < 0.05. The results indicate the efficiency of using PB design for screening processes. However, optimal concentration of the significant components can be determined by further statistical analysis.

Development of compatible fungal mixed culture for composting process of oil palm industrial waste

�Six filamentous fungal strains/isolates such as Aspergillus niger (A), Trichoderma viride (Tv), Trichoderma reesei (Tr), Penicillium sp. (P), Basidiomycete M1 (M1) and Panus tigrinus M609RQY (IMI 398363)(M6) were tested to find their mutual growth in the laboratory. Potato dextrose agar (PDA) as a media was used for their fifteen combinations and two different fungi were grown 4 cm apart in every combination. The results of this present study showed that the combinations of T. viride and Penicillium sp. (Tv/P), T. viride and Basidiomycete M1 (Tv/M1), T. reesei and P. tigrinus M609RQY (Tr/M6) may interact as compatible, while A. niger and T. viride (A/Tv), A. niger and T. reesei (A/Tr), T. viride and T. reesei (Tv/Tr) and Penicillium sp. And P. tigrinus M609RQY (P/M6) were partially compatible and the other combinations were incompatible or inhibited by each other. Furthermore, the cellulolytic fungus T. viride was the dominant in all its combinations, and its growth rate and hyphal expansion showed the highest responses as compared to all combinations. These compatible filamentous fungi would be useful for effective composting process in further study.

Effect of Process Parameters on Yield and Conversion of Jatropha Biodiesel in a Batch Reactor

In a quest for environmental friendly energy source with least pollutants emission due to issues of global warming coupled with dwindling reserve of the fossil fuel, researchers have intensified study on renewable fuels. Among these renewable energy sources, biodiesel stands prominent. Biodiesel production is largely by transesterification of transglycerides of fatty acids almost always in a batch reactor. Of importance in the yield generation and fatty acid methyl esters conversion is the feedstock purity, control of reagents use in production and operation parameters alteration. This is geared towards achieving optimum resource conservation while also minimizing cost and materials wastage. In this study biodiesel was produced from hydrolysate (free fatty acids from hydrolyzed Jatropha curcas oil) using calcinated niobic acid catalyst at controlled rates of process parameters. Yield and conversion up to 97.7% and 100% respectively of the alkyl esters produced. This informs the influence of process parameters significantly on the throughput of the final product.

Thermostable Lipases: an Overview of Production, Purification and Characterization

Thermostable lipases occupy a prominent position in aqueous and non-aqueous biocatalysis. Isolation of wild strains with novel properties has been on-going and recombinant strains are being constructed so as to meet the biotechnological applications of lipases. Different purification methods prove effective and the purity of the enzyme is dependent on the intended applications. Unlike medical and pharmaceutical applications where highly pure preparations are needed, partial purification can be sufficient for general applications. Thus, characterization associated with enzyme activity, specificity, thermostability, enatioselectivity and tolerance to various solvent systems are the prerequisite for thermostable lipase selection which make them highly demanding in lipase catalyzed reactions. This article intends to give an insight on thermostable lipases so as to stimulate researchers to explore other unique properties from wild and recombinant strains that could be of benefit for wider industrial applications.

Development of pretreatment of empty fruit bunches for enhanced enzymatic saccharification

To achieve an accomplished optimized condition for enzymatic saccharification of palm oil mill empty fruit bunches (EFB) for higher yield of sugar hydrolysis, a comprehensive pretreatment of EFB was carried out using the laboratory produced cellulase enzyme through bioconversion of palm oil mill effluent (POME) by the fungal strain, Trichoderma reesei RUT C-30. This study was conducted by using two different types of agents (physical and chemical). Heating, boiling and steaming are among the physical agents and different concentrations of nitric acid, sulfuric acid and sodium hydroxide (NaOH) were the chemical agents used for the pretreatment of EFB to enhance the enzymatic saccharification of EFB. NaOH was proved to be the best among all the pretreatment agents and 3% NaOH was far higher and 2.35 fold increment was achieved on the yield of reducing sugar (175.03 mg/g of EFB) after 96 h of saccharification. A maximum of 41.82% yield of reducing sugar was achieved with 5% (w/v) of EFB and 7% (v/v) of enzyme after 120 h of saccharification when eight important parameters, namely saccharification duration, EFB size, EFB dose, enzyme dose, Tween 80, triton 100, agitation and incubation temperature, were examined in an OFAT (one factor at-a-time) design.

Study the Growth of Microalgae in Palm Oil Mill Effluent Waste Water

This paper emphasizes mainly on the biomass productivity and lipids content of two microalgae strains known by their high lipids content namely: Botryoccoccus sudeticus and Chlorella vulgaris. These strains were first screened for the highest biomass and lipids content, then Plackett?Burman design was used to evaluate the significant media for the growth when using POME waste water as culture medium. Results show that Botryoccocus sudeticus contains high content of biomass and lipids yield. Moreover, all the three factors have positive effect on the biomass productivity, while using one nutrient factor gives much lower biomass. These results can be used further as an insight for optimizing the biomass and the oil productivity of the microalgae.

Chemical structure of sulfated polysaccharides from brown seaweed (Turbinaria turbinata)

ABSTRACT The chemical structure of three sulfated polysaccharides fractions (TtF1, TtF2, and TtF3) obtained from anion-exchange separation of aqueous extracts of brown seaweed (Turbinaria turbinate) were studied. The infrared spectra patterns showed that the fractions possess functional groups similar to that of sulfated polysaccharides. The sulfated polysaccharides fractions exhibited molecular weights of 223.5, 495.5, and 326.05 kDa, respectively, for TtF1, TtF2, and TtF3. 1H NMR spectra of TtF2 and TtF3 contain α-anomeric protons (5–5.6 ppm), ring protons (3.4–4.4), and methyl protons (1–1.3 ppm) while that of TtF1 only exhibited ring protons and methyl protons. Rheological data were fitted to power law which revealed that the fractions were Newtonian and/or presented weak pseudoplastic behavior. Consistency values increased with concentration in all fractions. Consistency values of TtF2 were the highest, followed by TtF1 and then TtF3. Thermal degradation patterns of TtF1 and TtF2 were similar but different from that of TtF3. This study confirmed that chemical and physical characteristics of sulfated polysaccharides fractions are interrelated and provided in-depth understanding of sulfated polysaccharides of brown algae.