Mashitah Mat Don

Biosorption of copper (II) onto immobilized cells of Pycnoporus sanguineus from aqueous solution : Equilibrium and kinetic studies

The ability of white-rot fungus, Pycnoporus sanguineus to adsorb copper (II) ions from aqueous solution is investigated in a batch system. The live fungus cells were immobilized into Ca-alginate gel to study the influence of pH, initial metal ions concentration, biomass loading and temperature on the biosorption capacity. The optimum uptake of Cu (II) ions was observed at pH 5 with a value of 2.76mg/g. Biosorption equilibrium data were best described by Langmuir isotherm model followed by Redlich-Peterson and Freundlich models, respectively. The biosorption kinetics followed the pseudo-second order and intraparticle diffusion equations. The thermodynamic parameters enthalpy change (10.16kJ/mol) and entropy change (33.78J/molK) were determined from the biosorption equilibrium data. The FTIR analysis showed that OH, NH, CH, CO, COOH and CN groups were involved in the biosorption of Cu (II) ions onto immobilized cells of P. sanguineus. The immobilized cells of P. sanguineus were capable of removing Cu (II) ions from aqueous solution.

Jewel of the seabed: sea cucumbers as nutritional and drug candidates

Marine sources have been attracting the attention of scientists and manufacturers worldwide hoping to find new alternatives for biological active substances. Promising new research indicates that sea cucumber, which is slug-like in appearance and has been a staple in Japan, China and other parts of East Asia since ancient times, is beginning to gain popularity as a dietary supplement in western countries. The roles of sea cucumber extracts in various physiological functions have spurred researchers to investigate the ability of sea cucumber to be an alternative in neutraceutical and medical applications. This article provides a brief introduction to sea cucumber and reviews its numerous bioactive compounds, such as triterpene glycosides, glycosaminoglycans, gangliosides, collagen, branched-chain fatty acid and lectins, which serve as potential sources of neutraceutical, pharmaceutical and cosmetic agents, thus providing a new platform in biochemical research.

Assessment of the properties, utilization, and preservation of rubberwood (Hevea brasiliensis): a case study in Malaysia

Rubber trees were introduced into the Malay Peninsula more than a century ago. The normal economical lifespan of a rubber tree is about 25 years, and, traditionally, rubberwood was used as firewood by the rural community. In recent decades, rubberwood has become an important timber for wood products, particularly in the furniture manufacturing sector, due to its attractive features, cream color, and good working properties. Sapstain, mold, and wooddecaying fungi are serious threats to rubberwood. Conventional chemical control has been a successful method of preventing staining fungal growth, but the effects of these chemicals are of concern because they create problems for the environment and public health. Thus, biological control has been recognized as an alternative approach to the problem. This article reviews the properties, potential utilization, and problems of protecting rubberwood against sapstain, mold, and wood-decaying fungi, and discusses the treatment methods available. Advances in biological control, particularly biofungicides, are emphasized as an alternative method for rubberwood treatment.

Nutrient improvement using statistical optimization for growth of Schizophyllum commune, and its antifungal activity against wood degrading fungi of rubberwood

Two statistical tools, Plackett‐Burman design (PBD) and Box‐Behnken design (BBD) were used to optimize the mycelia growth of Schizophyllum commune with different nutrient components. Results showed that 32.92 g/L of biomass were produced using a medium consisting of 18.74 g/L yeast extract, 38.65 g/L glucose, and 0.59 g/L MgSO4.7H2O. The experimental data fitted well with the model predicted values within 0.09 to 0.77% error. The biomass was also tested for antifungal activity against wood degrading fungi of rubberwood. Results showed that the minimum inhibitory concentration (MIC) values for antifungal activity range from 0.16 to 5.00 μg/μL. The GC‐MS analysis indicated that this fungus produced several compounds, such as glycerin, 2(3H)‐furanone, 5‐heptyldihydro‐, 4H‐pyran‐4‐one, 2,3‐dihydro‐3,5‐dihydroxy‐6‐methyl‐, and triacetin.

Assessment of bioethanol yield by S. cerevisiae grown on oil palm residues: Monte Carlo simulation and sensitivity analysis.

Oil palm trunk (OPT) sap was utilized for growth and bioethanol production by Saccharomycescerevisiae with addition of palm oil mill effluent (POME) as nutrients supplier. Maximum yield (YP/S) was attained at 0.464g bioethanol/g glucose presence in the OPT sap-POME-based media. However, OPT sap and POME are heterogeneous in properties and fermentation performance might change if it is repeated. Contribution of parametric uncertainty analysis on bioethanol fermentation performance was then assessed using Monte Carlo simulation (stochastic variable) to determine probability distributions due to fluctuation and variation of kinetic model parameters. Results showed that based on 100,000 samples tested, the yield (YP/S) ranged 0.423-0.501g/g. Sensitivity analysis was also done to evaluate the impact of each kinetic parameter on the fermentation performance. It is found that bioethanol fermentation highly depend on growth of the tested yeast.

Optimization of Process Variables for the Synthesis of Silver Nanoparticles by Pycnoporus sanguineus using Statistical Experimental Design

Sequential optimization strategy based on statistical experimental design and one-factor-at-a-time (OFAT) method were employed to optimize the process parameters for the enhancement of silver nanoparticles (AgNPs) production through biological synthesis using Pycnoporus sanguineus. Based on the OFAT method, three significant components influencing the size of AgNPs produced were identified as AgNO3 concentration, incubation temperature, and agitation speed. The optimum values of these process parameter for the synthesis of AgNPs were determined using response surface methodology (RSM) based on Box-Behnken design. The validity of the model developed was verified, and the statistical analysis showed that the optimum operating conditions were 0.001 M of AgNO3, 38°C, and 200 rpm with the smallest AgNPs produced at 14.86 nm. The disc diffusion method also suggested that AgNPs produced using optimum conditions have higher antimicrobial activity compared to the unoptimized AgNPs. The present study developed a robust operating condition for the production of AgNPs by P. sanguineus, which was 8.6-fold smaller than that obtained from un-optimized conditions.

Nonlinear process modeling of fructosyltransferase (FTase) using bootstrap re-sampling neural network model

Recently, the increased demand of fructooligosaccharides (FOS) as a functional food has alarmed researchers to screen and identify new strains capable of producing fructosyltransferase (FTase). FTase is the enzyme that converts the substrate (sucrose) to glucose and fructose. The characterization of complex sugar such as table sugar, brown sugar, molasses, etc. will be carried out and the sugar that contained the highest sucrose concentration will be selected as a substrate. Eight species of macro-fungi will be screened for its ability to produce FTase and only one strain with the highest FTase activity will be selected for further studies. In this work, neural networks (NN) have been chosen to model the process based on their excellent ‘resume’ in coping with nonlinear process. Bootstrap re-sampling method has been utilized in re-sampling the data in this work. This method has successfully modeled the process as shown in the results.

Modeling and Optimisation of Xylose Production by Enzymatic Hydrolysis using Neural Network and Particle Swarm Optimization

Abstract Particle swarm optimization (PSO) method is used for the optimization of an enzymatic hydrolysis process for the production of xylose from rice straw. The enzymatic hydrolysis process conditions such as temperature, agitation speed and concentration of enzyme were optimized by using PSO to obtain the optimum yield of xylose. Data collected from an experimental design using response surface methodology were necessitated to develop the neural network modeling. The neural network model is used as a model in objective function of PSO to predict the optimum conditions, which involved in the enzymatic hydrolysis process. The optimum value is obtained from the performance of the best particle swarm among the optimum conditions in PSO. The predicted optimum values were validated through the experiment of the enzymatic hydrolysis process. The optimum temperature, agitation speed and xylanase concentration is observed to be 50.3°C, 132 rpm and 1.6474 mg/ml, respectively. The optimal yield of xylose is predicted as 0.1845 mg/ml using PSO.

Flavonoid production by T. lactinea: screening of culture conditions via OFAT and optimization using response surface methodology (RSM)

The culture conditions for flavonoid production by the fungus Trametes lactinea was screened using one-factor-at-a-time (OFAT) and optimized with response surface methodology. T. Lactinea was found to grow well in Medium 3, and the highest flavonoid was produced in Medium 2. Medium 2 contains yeast extract, glucose, KH2PO4, Na2HPO4 · 12H2O, MgSO4 · 7H2O, and (NH4)2 · SO4, whereas Medium 3 contains yeast extract, glucose and peptone. Four selected parameters in OFAT were further optimized for flavonoid production by T. lactinea using response surface methodology via Box Behnken design (BBD). Interactions of culture conditions and optimization of the system were then studied using BBD with four levels of the four variables in a batch flask culture. Experimentation showed that the model developed based on BBD had predicted flavonoid production with R2=0.9983. The predicted flavonoid production was optimum (20.02 μg/mL) when the culture conditions were at 8.1 days of incubation period, 5.2 mL of inoculum, incubation temperature at 34.6°C, and the production medium with initial pH 6. The results indicated that BBD method was effective in optimizing the culture conditions of flavonoid production by T.lactinea.

The feasibility of growing cells of Saccharomyces cerevisiae for citronellol production in a continuous-closed-gas-loop bioreactor (CCGLB)

The present work aims to address the gas-phase biotransformation of geraniol into citronellol using growing cells of Saccharomyces cerevisiae (bakers yeast) in a continuous-closed-gas-loop bioreactor (CCGLB). This study revealed that the gaseous geraniol had a severe effect on the production of biomass during the growing cell biotransformation resulting in the decrease in the specific growth rate from 0.07 to 0.05 h⁻¹. The rate of reaction of the growing cell biotransformation was strongly affected by agitation and substrate flow rates. The highest citronellol concentration of 1.18 g/L and initial rate of reaction of 7.06 × 10⁻⁴ g/min g(cell) were obtained at 500 rpm and 8 L/min, respectively.