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Articles by M.A. Hassan
Total Records ( 16 ) for M.A. Hassan
  A. Sulaiman , M.R. Zakaria , M.A. Hassan , Y. Shirai and Z. Busu
  Problem statement: Refined Glycerin Wash Water (RGWW) from the oleochemical industry contains high Chemical Oxygen Demand (COD) and requires proper treatment before disposal. Unfortunately the wash water also contains high concentration of sodium chloride (NaCl) that could cause inhibition to the normal biological treatment process. However, there is feasibility of co-digesting the RGWW and Palm Oil Mill Effluent (POME) for its treatment and methane recovery. Approach: A large 500 m3 semi-commercial closed digester tank was used to study the effect of co-digesting POME and RGWW under mesophilic condition at different RGWW percentage. The digester performance in terms of COD removal efficiency and methane production rate and stability based on total Volatile Fatty Acids (VFA) accumulation, Mixed Liquor Volatile Suspended Solid (MLVSS) and pH were evaluated. Results: At 1.0% of RGWW co-digested, both COD removal efficiency and methane production rate showed satisfactory results with higher than 90% and 505 m3 day-1, respectively. However, once the percentage was increased to a maximum of 5.25%, COD removal efficiency remains high but the methane production rate reduced significantly down to 307 m3 day-1. At this stage, the digester was already unstable with high total VFA recorded of 913 mg L-1 and low cells concentration of 8.58 g L-1. This was probably due to the effect of plasmolysis on the methanogens at high concentration of NaCl in the digester of nearly 4000 mg L-1. Conclusion: Co-digesting of RGWW with high NaCl content and POME is satisfactory for COD removal but not for increasing the methane production.
  S. Abd-Aziz , L.G.A. Ong , M.A. Hassan and M.I.A. Karim
  The aims of this study are to optimised the process parameters involved for submerged fermentation of mannanase by Aspergillus niger FTC5003 using palm kernel cake (PKC) as carbon source. The parameters investigated include temperature, agitation speed, inoculum size and PKC concentration. The submerged fermentation was carried out for 10 days by using palm kernel cake as the sole carbon source with the addition of nitrogen source. Palm kernel cake can be considered as a suitable carbon source for the enzyme production due to it mainly consist of mannan and galactomannan, which is hemicellulose. The mannanase enzyme production using the optimised fermentation condition, which was conducted at agitation speed of 200 rpm, temperature 35 °C, 1x104 spores mL-1 of inoculum size and 2% of palm kernel cake with productivity of 13.00 U/mL/day.
  H.M.Y. Nazlina , A.R. Nor Aini , F. Ismail , M.Z.M. Yusof and M.A. Hassan
  The aim of this study was to establish the optimum operating parameters for biohydrogen production from food waste. Batch fermentation was conducted using a 150 mL serum vial incubated in anaerobic condition. Heat-treated Palm Oil Mill Effluent (POME) sludge was used as the seed culture for biohydrogen production. Biohydrogen production was performed at different temperatures (35, 40, 50, 55 and 60°C), initial pH (5, 6, 7 and 8) and various compositions of sludge to substrate (10:90, 20:80, 30:70 and 40:60% (v/v)). The highest biohydrogen yield was 593 mL H2 g-1 carbohydrate for the experiment conducted at a temperature of 55°C, initial pH 7 and composition of sludge to substrate at 30:70% (v/v). The biohydrogen production from the waste was accompanied by the production of organic acids and the ratio of Hac/HBu was 0.87. Treatment efficiency as shown by Total Carbohydrate (TC), Total Suspended Solids (TSS) and Total Volatile Solids (TVS) reduction were 38, 25 and 18%, respectively.
  K. Simarani , M.A. Hassan , S. Abd-Aziz , M. Wakisaka and Y. Shirai
  Sterilization process of oil palm fruits by-product can be satisfactorily used as alternative degradation method in production of value-added products from Empty Fruit Bunch (EFB). It could be considered as an auto hydrolysis technique in the regular pre-treatment methods. Other studies on lignocelluloses showed that they increase the pore volume of the wood which increases the available surface area for the enzyme. Changes in structure and properties of the EFB cellulose caused by sterilization were investigated by x-ray diffractometry and enzymatic hydrolysis of cellulosic biomass for fermentable sugar production (glucose). The enzymatic hydrolysis results showed that the highest hydrolysis of 53.77±1.38% (g/g biomass) conversion was obtained in EFB after 72 h incubation with glucose production, (Yp/x) of 12.55±0.33 g L-1. The increase in Crystallinity Index (CrI) of sterilized biomass increased the yield of glucose (g L-1) up to 44.55% compared to Fresh Fruit Bunches (FFB) as a control. Results obtained appear to be commercial significance showing the potential of sterilization process in a palm oil mill as a zero cost pre-treatment for the effective utilization of empty fruit bunch biomass for value added production from the palm oil industry.
  S.M. Akhir , S. Abd-Aziz , M.M. Salleh , R.A. Rahman , R.M. Illias and M.A. Hassan
  The optimization of fermentation medium for the production of chitinase by Bacillus licheniformis TH-1 was carried out using Response Surface Methodology (RSM) based on the two level factorial design. This procedure limited the number of actual experiments performed while allowing for possible interactions between 5 components. RSM was adopted to derive a statistical model for the effect of chitin, Yeast Extract (YE), peptone, NaNO3 and K2HPO4 on chitinase production. The p-value of the coefficient for linear effects of chitin, peptone and YE was 0.0001, suggesting that this was the principal experiment variable, having the greatest effect on the production of chitinase. The optimal combinations of media constituent for maximum chitinase production are determined as 10 g L-1 chitin, 0.5 g L-1 YE, 0.5 g L-1 peptone, 2.55 g L-1 NaNO3 and 1.55 g L-1 K2HPO4. The optimization of the fermentation medium resulted not only in a 5.4 fold increase of enzyme activity compared to unoptimized medium but also a reduced amount of the required medium constituents. The response surface analysis provided a useful tool for the optimization of a low cost enzyme producing medium for potential use on an industrial scale.
  Z. Zanirun , S. Abd-Aziz , F.H. Ling and M.A. Hassan
  Lignin peroxidase has been extensively studied and has been reported to produce by white rot fungus. The highest lignin peroxidase producer from local isolates, identified as Pycnoporus sp. was selected for the optimisation study. Factorial design approach was significant to determine the optimum conditions that significantly influenced the production of lignin peroxidase by Pycnoporus sp. Several factors were selected in a range indicated by -1 and +1 for lower and upper level, respectively. The results of ANOVA were analysed to check for the significant factors. Optimum condition for the highest lignin peroxidase activity of 51.1 U L-1 was obtained at 24 mM of nitrogen concentration, agitation speed at 110 rpm, pH 3.5, inoculum concentration of 6x106 spores mL-1 and with the addition of inducer (veratryl alcohol). Considering the results obtained, this statistical design was effective in improving the lignin peroxidase production from Pycnoporus sp.
  N.K. Abu Bakar , S. Abd-Aziz , M.A. Hassan and F.M. Ghazali
  In order to construct cellulolytic fungal mixed cultures, screening and isolation of cellulolytic fungi was done using rotten oil palm fruit bunches as microorganism source. Three isolated fungi had shown the ability to degrade cellulose based on decolorization of CMC selective agar using Gram’s iodine as color indicator. However, only two strains; KS1 and KS5 were selected for construction fungal mixed culture. Based on fungal interaction evaluation test done on PDA agar, both strains showed contact deadlock inhibition interaction with each other. In correlation to cellulase enzymes production, mixed cultures of strains KS1 and KS5 showed low enzymes activity compared to pure culture system. Although, the cellulase enzymes production is low, total cellulase enzymes composition was better than in pure culture system individually.
  A.S. Baharuddin , M. Wakisaka , Y. Shirai , S. Abd-Aziz , N.A. Abdul Rahman and M.A. Hassan
  The main objective of this study is to investigate the physicochemical changes of the co-composting Empty Fruit Bunch (EFB) with partially treated palm oil mill effluent (POME) in pilot scale. The partially treated POME from anaerobic pond was sprayed onto the shredded EFB throughout the treatment. The composting materials were turned over one to three times per week for aeration. Temperature and oxygen were monitored at different depths of the composting piles. Parameters such as C, N, pH, nutrients, heavy metals and total bacteria count were also determined. The temperature was increased up to 58.5 °C at day three of treatment, after that fluctuated between 50 to 62°C and then decreased in the latter stage of the process. The pH of the system (7.75-8.10) did not vary significantly during the treatment period while moisture content was reduced from 65-75% to about 60% at the end of the treatment. The initial C/N ratio of 45 was significantly reduced to 12 after 60 days of composting. The final cured compost contained a considerable amount of nutrients (carbon, nitrogen, phosphorus, potassium, calcium, magnesium, sulfur and iron) and trace amounts of manganese, zinc, copper. In addition, very low levels of heavy metals were detected in the compost. The number of bacteria involved in the composting process was decreased at the end of the composting period. The results obtained indicated that pilot scale of co-composting EFB with partially treated POME gave acceptable quality of compost and ease in operation. The compost product may useful in palm oil plantation as fertilizer and soil amendment.
  M.Z.M. Yusoff , M.A. Hassan , S. Abd-Aziz and N.A.A. Rahman
  Feasibility study of biohydrogen production from Palm Oil Mill Effluent (POME) using POME sludge as a mixed culture of natural inoculum was conducted. The experiment was done using a 150 mL serum bottle and 50 L Continuous Stirred Tank Reactor (CSTR) in batch and continuous modes, respectively. The biogas produced from both fermentations was free from methane due to heat treatment of the sludge prior to inoculation. The results obtained showed that the biohydrogen content in 150 mL serum bottle was higher (70%) than that of 50 L CSTR (25%). The biohydrogen rates for serum bottle and 50 L bioreactor were 74 and 33 NmL/h/L, respectively. Butyrate, propionate and acetate were the main soluble metabolites produced during the fermentation and reduced the pH of broth.
  A.M. Roslan , M.A. Hassan , S. Abd-Aziz and P.L. Yee
  In this study, Palm Oil Mill Effluent (POME) was selected as supplement in rice straw fermentation to replace commercial inducer due to its high concentration of simple carbohydrate and nitrogenous compounds. The cellulase activity of the enzyme produced were then determined individually and combined (enzyme cocktail) to observe increment in cellulase activity. Individually, filter paperase (FPAse), carboxymethyl cellulase (CMCase) and β-glucosidase activities increase for all 3 fungi used except FPAse for Aspergillus sp. (NEW). Highest FPAse and CMCase activities increment observed was from Phanerochaete chrysosporium which were 72 and 236% increment, respectively, while highest β-glucosidase activity was from Aspergillus terreus (AT) which was 298% increment. Meanwhile in cocktail cellulase, synergistic effect was observed especially for FPAse activity whereby highest FPAse activity observed was by cocktail of all the three species of fungi which show 393% increment. Though CMCase increment was observed in this mode, it was not as high as FPAse where the highest CMCase activity observed was cocktail by the three fungal species which increased by 41%. However, in β-glucosidase activity, only cocktail of NEW and AT showed increment from their average activity which was by 6%. It seems that β-glucosidase activity plays major role in determining the total cellulase activity. In the nutshell, supplementation of POME can improve cellulase activity.
  A.F. Hamisan , S. Abd-Aziz , K. Kamaruddin , U.K.Md. Shah , N. Shahab and M.A. Hassan
  In this study, Oil Palm Empty Fruit Bunch (OPEFB) were subjected to chemical and microbial pretreatment for bioconversion of lignocellulosic biomass to fermentable sugars. For chemical pretreatment, 2% (w/v) sodium hydroxide (NaOH) was been used for delignification while for microbial pretreatment, Phanerochaete chrysosporium ATCC 32629 was used as model microorganism by liquid and solid state culture techniques. Microbial pretreatment showed significant lignin removal with longer delignification time as compared to chemical pretreatment. For the same value of Klason lignin, delignification by chemical pretreatment need only 3 h as compared to 7 days for microbial pretreatment. The optimum value of Klason lignin for microbial pretreatment and chemical pretreatment were 5.89 and 5.93, respectively. In conclusion, delignification of OPEFB can be achieved via chemical and microbial pretreatment.
  A.M. Roslan , P.L. Yee , U.K.M. Shah , S.A. Aziz and M.A. Hassan
  Cellulase production in situ was considered as one of the alternatives to reduce bioethanol production cost. In this study, cellulase enzyme was produced from rice straw by locally isolated Aspergillus sp. in solid state fermentation. The crude cellulase was measured to have activity of 6.3 FPU g-1 rice straw. The rice straw was pretreated by few cycles of wet disc milling prior saccharified it using the crude cellulase produced. More than 90% glucose from total cellulose was released by the saccharification. The saccharified product was subjected to fermentation by yeast. The highest bioethanol yield produced from the fermentation was 0.102 g g-1 rice straw which is equivalent to 62.61% of theoretical bioethanol yield. It was concluded that the use of crude cellulase from rice straw onto rice straw can lead to a good yield of bioethanol, provided an effective pretreatment was used.
  M.Y. Waziri , W.J. Leong , M.A. Hassan and M. Monsi
  Problem statement: The major weaknesses of Newton method for nonlinear equations entail computation of Jacobian matrix and solving systems of n linear equations in each of the iterations. Approach: In some extent function derivatives are quit costly and Jacobian is computationally expensive which requires evaluation (storage) of nxn matrix in every iteration. Results: This storage requirement became unrealistic when n becomes large. We proposed a new method that approximates Jacobian into diagonal matrix which aims at reducing the storage requirement, computational cost and CPU time, as well as avoiding solving n linear equations in each iterations. Conclusion/Recommendations: The proposed method is significantly cheaper than Newton’s method and very much faster than fixed Newton’s method also suitable for small, medium and large scale nonlinear systems with dense or sparse Jacobian. Numerical experiments were carried out which shows that, the proposed method is very encouraging.
  S. Abd-Aziz , N.A. Ab-Razak , M.H. Musa and M.A. Hassan
  The aim of this study is to produce and profile the mannan-degrading enzymes from local fungal isolates by submerged fermentation and saccharification of PKC. Results showed that Aspergillus niger and Sclerotium rolfsii can produce mannan-degrading enzymes. The fungi were grown in submerged fermentation of PKC to produce mannan-degrading enzymes. The highest alpha-galactosidase was obtained on day 13 of fermentation (0.128 U mL-1) when using A. niger and on day 18 (0.126 U mL-1) when using S. rolfsii. Analysis also showed that enzyme activities for beta-mannanase using S. rolfsii were the highest at day 17 (3.166 U mL-1) and for A. niger (2.482 U mL-1) at day 8. Meanwhile the highest beta-mannosidase were obtained at day 16 for A. niger (0.128 U mL-1) and for S. rolfsii at day 16 (0.116 U mL-1).
  S.K. Hong , Y. Shirai , A.R. Nor Aini and M.A. Hassan
  The aim of this study was to improve organic acids production in semi and continuous anaerobic treatment of Palm Oil Mill Effluent (POME) using a locally fabricated 50 L Continuously Stirred Tank Reactor (CSTR). The organic acids obtained were then used for polyhydroxyalkanoate (PHA) production by Ralstonia eutropha ATCC 17699 in a 2 L bioreactor. The conditions used in the anaerobic treatment were controlled pH 6.5, sludge to POME ratio at 1:1 and Hydraulic Retention Time (HRT) of 4 days. The organic acids obtained were about 15 g L-1 at steady state for both treatments and the organic acids yield (based on BOD) was 58.3%. The selected organic acids obtained were acetic (51.5%), propionic (27%) and butyric (21.5%) acid. The recovery of the clarified and concentrated organic acids from the treated POME was made using a two-steps evaporation process. The clarified organic acids (distillate) obtained were comprising of 44.6, 20.1 and 22.5 g L-1 acetic, propionic and butyric acids, respectively with a recovery of 76%. The organic acids collected were then used for polyhydroxyalkanoates accumulation by Ralstonia eutropha ATCC 17699 using pH stat fed-batch fermentation under nitrogen limitation of C/N 40 in a 2 L fermenter. The highest PHA concentration of 11.4 g L-1 (>90% w/w) was achieved in this process.
  Z. Shahrim , V. Sabaratnam , N.A.A. Rahman , S. Abd-Aziz , M.A. Hassan and M.I.A. Karim
  Trichoderma sp. KUPM0001 showed good growth during solid substrate fermentation (SSF) of sago pith residue known as hampas, supplemented with 10% (v/w) of mineral salts solution containing 0.5% (w/v) (83.3 mM) urea as nitrogen source and an initial moisture content of 80% (v/w). Mycelium suspension of 10% (v/w) density was used as initial inoculum and SSF was carried out at 25±2°C in static condition over a period of 120 h. The parameters optimized included the initial moisture content of the substrate, mineral salts solution, urea concentration, inoculum density, incubation temperature and incubation time. Without optimized condition, the maximum reducing sugar obtained was 24 mg mL-1 compared to 46 mg mL-1 substrate during optimized SSF after 96 h incubation. The optimum parameters obtained were 80% (v/w) of initial moisture; 10% (v/w) of inoculums size; 1.0% of urea in 20% (w/v) of mineral solution and incubated at 30±2°C. The enzyme activities using optimized condition gave maximum α-amylase, glucoamylase, carboxymethyl cellulase, filter paperase and β-glucosidase of 3.19, 2.22, 1.66, 1.11 and 1.48 U mL-1, respectively.
 
 
 
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