Norazwina Zainol

Adsorption of vanillin using macroporous resin H103

Six resins (Amberlite XAD-16, Amberlite XAD-2, Sepabeads SP207, DIAION HP-20, DM11 and H103) were tested for vanillin adsorption in aqueous solution. All of the resins gave more than 95% adsorption rate except for Amberlite XAD-2 and DM11. Resin H103 was selected for the subsequent work due to its high adsorption capacity and low cost. A kinetic analysis revealed that the adsorption process followed pseudo-second-order kinetic model and occurred rapidly. The equilibrium point was reached after 90 minutes of reaction. Adsorption isotherm was also determined at 25 °C and it was fitted to Langmuir and Freundlich equations using linear regression and non-linear regression (sum of squares) methods. The regression shows that the adsorption of vanillin onto resin H103 followed Langmuir model (R2 = 0.9984) with a maximum capacity of 73.015 mg/g.

Kinetics of Biogas Production from Banana Stem Waste

Biogas produced in anaerobic digesters consists of methane (50%–80%), carbon dioxide (20%–50%), and trace levels of other gases such as hydrogen, carbon monoxide, nitrogen, oxygen, and hydrogen sulfide. Anaerobic digestion is a biological process in which organic material is decomposed by bacteria in the absence of air. The general technology of anaerobic digestion of complex organic matter is well known and has been applied for over 60 years as part of domestic sewage treatment to stabilize organic wastes. Bal & Dhagat (2001) points out that the anaerobic process is more advantageous than the aerobic process in organic waste treatment because of the high degree of waste stabilization, low production of excess biological sludge, low nutrient requirement and production of methane gas as a useful byproduct. Several studies have been carried out for evaluating kinetic parameters and model equations for anaerobic digestion by Siles et al. (2010), Borja et al. (2005), Jimenez et al. (2004), Raposo et al. (2009), Rincon et al. (2009) and Hu et al. (2002); these are all based on the Monod kinetic model (Monod 1950) and on the revised kinetic model developed by Chen et al. (1980) and Hashimoto et al. (1981).

Kinetic Modeling of Biogas Generation from Banana Stem Waste

A kinetic model for biogas generation from banana stem waste was proposed on the basis of the obtained experimental results. The system consists of an anaerobic sequencing batch reactor for the first stage and an anaerobic fixed bed reactor for the second stage, which is operating at hydraulic retention times (HRT) of nine days. The process was conducted at ambient temperature for the first stage and thermophilic temperature for the second stage. Four differential equations described the overall process. This study employed first order kinetics for hydrolysis of non-soluble organic matter and a Michaelis–Menten equation type for the soluble organic matter decomposition, total volatile acids consumption and methane production. The following kinetics constants were obtained for the above-mentioned anaerobic stages: (a) hydrolysis and solubilization of organic matter: k1 (kinetic constant for non-soluble organic matter degradation): 0.0037 day−1; k2 (maximum rate of soluble organic matter production): 0.0241 g soluble chemical oxygen demand (SCOD)/l day; k3 (saturation constant): 0.0236 g SCOD/l; (b) acidogenesis: k4 (maximum rate of soluble organic matter degradation): 0.0086 g SCOD/l day; k5 (saturation constant): 0.0189 g SCOD/l; and (c) methanogenesis: k6 (maximum rate of acetic acid (TVA) consumption): 0.0092 g TVA/l day; and k7 (saturation constant): 0.0003 g TVA/l. The kinetic constants obtained and the proposed equations were used to simulate the different steps of the anaerobic digestion process of banana stem waste and to obtain the theoretical values of non-soluble and soluble CODs, TVA and methane production.

Production of Lovastatin by Penicillium spp. Soil microfungi

Lovastatin is an important fungal secondary metabolite inhibiting the enzyme which catalyzes a rate-limiting step in the biosynthesis of cholesterol. As microfungi of the genus Penicillium are active producers of cholesterol lowering agents (statins), studies of this genus have gained considerable momentum. In Malaysia, both agricultural soils and those of natural ecosystems are valuable sources of filamentous fungi, whose biotechnological potential in terms of lovastatin production has not been well investigated. The aim of the present study is to determine lovastatin-producing potential of Penicillium spp. microfungi isolated from soil in Pahang State (Malaysia). Fungal cultures were isolated, purified, and classified based on characters of colony morphology and microscopic features. All identified representatives of Penicillium were tested for their ability to produce lovastatin. Isolates were cultivated in submerged fermentation. High-performance liquid chromatography (HPLC) was used for detection of lovastatin. Among 54 fungal cultures examined, four Penicillium strains were confirmed to produce this statin. The isolate Penicillium sp. ESF2M was the strongest lovastatin producer, with a yield of 20 mg/l. This strain should now be subjected to a further strain improvement program to maximize the yield of this important statin.

Biogas production from banana stem waste: optimisation of 10 l sequencing batch reactor

The performance of biogas production using banana stem waste in anaerobic system was investigated. Mixed culture for this study was from banana plantation soil and acclimatized in anaerobic condition. The performance was tested under the conditions of various temperatures (26degC-40degC), organic loading rates (OLR) (0.4 g TS/l.d-2 gTS/l.d), and hydraulic retention times (HRT) (3 d-20 d). Conditions for temperature, OLR and HRT in this study was based on the best range obtained from literature review The optimization test was done using design-expert software version 6.0.4 was utilized in this research to design the experiments and optimize the system. It was found that for maximum biogas yield the levels of the variables are as follows: temperature = 35.8degC, OLR = 1.42 gTS/l.d and HRT = 11.7 d. Experiments conducted with these optimised levels of variables gave an average biogas yield of 1.95 l/g COD. Factor analysis to both system discovered that all factors studied (OLR, HRT and temperature) gave significant effect to biogas production process.

Optimization of Ferulic Acid Production from Oil Palm Frond Bagasse

Ferulic acid (FA) is an organic acid that possesses multiple physiological properties including anti-oxidant, anti-microbial, anti-inflammatory, anti-thrombosis and anti-cancer activities. The applications of FA include being the source for vanillin and preservative production, thin film for food packaging, food supplement and skin care products. Oil palm frond (OPF) is the leaf and the branch part of the oil palm tree. In Malaysia, OPF is found in abundance as it is one of the by-products of the palm oil industry. The oil palm frond bagasse (OPFB) is obtained after some treatments that include pressing and drying of OPF, of which the resulting fibre is used for subsequent processes. Choice of using enzymatic hydrolysis to produce FA is more attractive compared to conventional chemical hydrolysis as enzymatic hydrolysis mainly focuses on utilizing the reaction caused by feruloyl esterase (FAE) to release FA from polysaccharide.

Process Simulation of Anaerobic Digestion Process for Municipal Solid Waste Treatment

A simulation of the anaerobic digestion process for municipal solid waste (MSW) treatment has been carried out using Aspen Plus software. Anaerobic digestion uses enzymes to solubilise particulate organic compounds so that they can be easily separated from inert waste such as plastic, metals and textiles. The complex substrates such as proteins, carbohydrates and fats are hydrolyzed into their respective monomers, such as amino acids, glucose and fatty acids. The hydrolyzed monomers then are converted into different volatile fatty acids (VFAs); later the VFAs are converted into carbon dioxide, acetic acid and hydrogen. A model of the anaerobic digestion process is represented by RSTOIC and RCSTR reactors in Aspen Plus. The hydrolysis reactions occur in RSTOIC reactor; meanwhile, amino acid degradation, acidogenic and acetogenic reactions are implemented in RCSTR reactor. The amount of dry matter content in bioliquid was 20 wt% which mainly consists of VFA. Sensitivity analysis has been performed in order to study the effect of residence time for the production of organic liquid fraction (bioliquid). The amount of bioliquid produced was increased as residence time was increased.

Data on modeling mycelium growth in Pleurotus sp. cultivation by using agricultural wastes via two level factorial analysis

In this article, five variables including type of substrates, sizes of substrates, mass ratio of spawn to substrates (SP/SS), temperature and pretreatment of substrates were used to model mycelium growth in Pleurotus sp. (oyster mushroom) cultivation by using agricultural wastes via two level factorial analysis. Two different substrates which were empty fruit bunch (EFB) and sugarcane bagasse (SB) were used. Analysis of Variance (ANOVA) for both mycelium extension rate (M) and nitrogen concentration in mycelium (N) showed that the confidence level was greater than 95% while p-value of both models were less than 0.05 which is significant. The coefficient of determination (R2) for both M and N were 0.8829 and 0.9819 respectively. From the experiment, the best condition to achieve maximum M (0.8 cm/day) and N (656 mg/L) was by using substrate B, 2.5 cm size of substrate, 1:14 for SP/SS, incubated at ambient temperature and application of steam treatment. The data showed that EFB can be used to replace sawdust as a media for the oyster mushroom cultivation. Data analysis was performed using Design Expert version 7.0.

Fatty acid profile from immobilised Chlorella vulgaris cells in different matrices

ABSTRACT The immobilisation of Chlorella vulgaris 211/11B entrapped in combinations of natural matrices to simplify the harvesting process was demonstrated in this study. Three combinations of matrices composed of calcium alginate (CA) and sodium alginate (SA), sodium carboxymethyl cellulose (CMC) and SA, and mixed matrices (SA, CA, and CMC) were investigated. The number of cells grown for each immobilised matrix to microalgae volume ratios (0.2:1–1:1) were explored and compared with using SA solely as a control. The optimum volume ratios obtained were 1:1 for SA, 0.3:1 for CA and SA, 1:1 for CMC and SA, and 0.3:1 for mixed matrices. The immobilised microalgae of mixed matrices exhibited the highest number of cells with 1.72 × 109 cells/mL at day 10 and 30.43% of oil extraction yield followed by CA and SA (24.29%), CMC and SA (13.00%), and SA (6.71%). Combining SA, CA, and CMC had formed a suitable structure which improved the growth of C. vulgaris and increased the lipid production compared to the immobilisation using single matrix. Besides, the fatty acids profile of the oil extracted indicates a high potential for biodiesel production.

Industry Involvement in Undergraduate Research Project for Chemical Engineering (Biotechnology) Programme

This paper reported on industry involvement in Undergraduate Research Project (URP) course. During the final year of study, Chemical Engineering (Biotechnology) (BKB) students were required to conduct a final year project. Undergraduate Research Project (URP) was divided into two which were URP I and URP II. In URP I, students have to prepare a research proposal and URP II was the continuation of URP I. In URP II the students were required to conduct the research and produce the dissertation. Rubrics for each evaluation have been developed to clearly define the assessments. In order to ensure a strong connection between students, staff and industry, BKB students were required to have at least 15% industrially linked/based URP topics. Starting from 2012, the faculty has invited external examiners from research institution and industries to assess students during their URP II presentation seminar. The presentation seminar was successfully conducted with the involvement of 14 industrial academic panels. The panels came from various industries, research institutes and consultation companies such as Petronas, MTBE Malaysia, Bio tropics Malaysia, MOX Gases, FRIM and Sime Darby. Their recommendations and suggestions during the presentation projects have benefited all students and lecturer towards improving their research works. Other than that, the requirement to have at least 15% industrially linked URP topics has strengthened the relationship between the faculty and industry. In addition, several URP projects has been sent for research exhibition, internal and externally.