Alawi Sulaiman

A Review: Potential Usage of Cellulose Nanofibers (CNF) for Enzyme Immobilization via Covalent Interactions

Nanobiocatalysis is a new frontier of emerging nanosized material support in enzyme immobilization application. This paper is about a comprehensive review on cellulose nanofibers (CNF), including their structure, surface modification, chemical coupling for enzyme immobilization, and potential applications. The CNF surface consists of mainly –OH functional group that can be directly interacted weakly with enzyme, and its binding can be improved by surface modification and interaction of chemical coupling that forms a strong and stable covalent immobilization of enzyme. The knowledge of covalent interaction for enzyme immobilization is important to provide more efficient interaction between CNF support and enzyme molecule. Enzyme immobilization onto CNF is having potential for improving enzymatic performance and production yield, as well as contributing toward green technology and sustainable sources.

Influential Parameters on Biomethane Generation in Anaerobic Wastewater Treatment Plants

Meisam Tabatabaei1,2, Alawi Sulaiman3, Ali M. Nikbakht4, Norjan Yusof5 and Ghasem Najafpour6 1Microbial Biotechnology and Biosafety Department, Agricultural Biotechnology Research Institute of Iran (ABRII), Karaj 2Department of Bioprocess Technology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Selangor 3Faculty of Plantation and Agrotechnology, Universiti Teknologi MARA, Shah Alam 4Department of Farm Machinery Engineering Faculty of Agriculture,Urmia University, Urmia 5Department of Biology, Faculty of Science and Mathematics Universiti Pendidikan Sultan Idris , Tanjong Malim, Perak 6Biotechnology Research Lab., Faculty of Chemical Engineering Noshirvani University of Technology, Babol 1,4,6Iran 2,3,5Malaysia

Enzymatic saccharification of Tapioca processing wastes into biosugars through immobilization technology (Mini Review)

Article history: Cassava is very popular in Nigeria, Brazil, Thailand and Indonesia. The global cassava production is currently estimated at more than 200 million tons and the trend is increasing due to higher demand for food products. Together with food products, huge amounts of cassava wastes are also produced including cassava pulp, peel and starchy wastewater. To ensure the sustainability of this industry, these wastes must be properly managed to reduce serious threat to the environment and among the strategies to achieve that is to convert them into biosugars. Later on, biosugars could be converted into other end products such as bioethanol. The objective of this paper is to highlight the technical feasibility and potentials of converting cassava processing wastes into biosugars by understanding their generation and mass balance at the processing stage. Moreover, enzyme immobilization technology for better biosugar conversion and future trends are also discussed.

Effects of aeration rate on degradation process of oil palm empty fruit bunch with kinetic-dynamic modeling

The effect of different aeration rates on the organic matter (OM) degradation during the active phase of oil palm empty fruit bunch (EFB)-rabbit manure co-composting process under constant forced-aeration system has been studied. Four different aeration rates, 0.13 L min(-1) kg(DM)(-1),0.26 L min(-1) kg(DM)(-1),0.49 L min(-1) kg(DM)(-1) and 0.74 L min(-1) kg(DM)(-1) were applied. 0.26 L min(-1) kg(DM)(-1) provided enough oxygen level (10%) for the rest of composting period, showing 40.5% of OM reduction that is better than other aeration rates. A dynamic mathematical model describing OM degradation, based on the ratio between OM content and initial OM content with correction functions of moisture content, free air space, oxygen and temperature has been proposed.

Biochemical Modulation of Lipid Pathway in Microalgae Dunaliella sp. for Biodiesel Production.

Exploitation of renewable sources of energy such as algal biodiesel could turn energy supplies problem around. Studies on a locally isolated strain of Dunaliella sp. showed that the mean lipid content in cultures enriched by 200 mg L−1 myoinositol was raised by around 33% (1.5 times higher than the control). Similarly, higher lipid productivity values were achieved in cultures treated by 100 and 200 mg L−1 myoinositol. Fluorometry analyses (microplate fluorescence and flow cytometry) revealed increased oil accumulation in the Nile red-stained algal samples. Moreover, it was predicted that biodiesel produced from myoinositol-treated cells possessed improved oxidative stability, cetane number, and cloud point values. From the genomic point of view, real-time analyses revealed that myoinositol negatively influenced transcript abundance of AccD gene (one of the key genes involved in lipid production pathway) due to feedback inhibition and that its positive effect must have been exerted through other genes. The findings of the current research are not to interprete that myoinositol supplementation could answer all the challenges faced in microalgal biodiesel production but instead to show that “there is a there there” for biochemical modulation strategies, which we achieved, increased algal oil quantity and enhanced resultant biodiesel quality.

Effect of Agitation Speed for Enzymatic Hydrolysis of Tapioca Slurry Using Encapsulated Enzymes in an Enzyme Bioreactor

Agitation speed is an important factor in the industrial application for the mixing efficiency in order to increase productivity. In this study, the effect of agitation speed was investigated in a stirred bioreactor for hydrolysis of tapioca slurry into glucose by using encapsulated enzymes within calcium alginate-clay (alg-clay) beads. The hydrolysis process was tested at various agitation speeds from 40 to 200 rpm. The stability of alg-clay beads was examined in term of morphology of beads, enzyme leaching behavior and enzymes activity. The morphology of the alg-clay beads was investigated by Field Emission Scanning Electron Microscopy (FESEM). It was found that vigorous speed ruptured the beads structure. The result also showed that by increasing the agitation speed, the leakage of enzymes also increased. Therefore, it can be concluded that there was a strong correlation between the speed of agitation and the beads morphology. The optimum agitation speed which gave the highest amount of enzymes activity was 120 rpm.

Preliminary study of oil palm decanter cake natural polymer composite (OPDC-NPC)

Palm oil industry produces huge amount of oil palm decanter cake (OPDC). Currently it is not yet commercialized however due to its characteristics, it can be used to produce oil palm decanter cake natural polymer composite (OPDC-NPC). NPC is a type of material made by combining natural fiber with polymer. Therefore the objective of this paper is to produce NPC from OPDC and then determine its mechanical and physical properties such as elasticity, stiffness, tensile strength and water absorption rate. The OPDC samples were collected from Felda Trolak Palm Oil Mill. Prior to NPC development, the oil was removed from OPDC using hexane soxhlet extraction method. OPDC-NPC was fabricated using molding method where the mixture of 95% polypropylene (PP) and 5% OPDC were mixed using twin-screw extruder. The results showed that OPDC-NPC has an elasticity of 2231 MPa, stiffness of 30 MPa, tensile strength of 32 MPa and water absorption rate of 0.16 % which was slightly better with the other types of fibers.

Nanoclay Supporting Materials for Enzymes Immobilization: Kinetics Investigation of Free and Immobilized System

In this paper, the kinetic parameters of free and encapsulated enzymes in the calcium alginate-clay beads were determined using Lineweaver-Burk plot. The Michaelis constant, Km of free alpha-amylase, glucoamylase and cellulase were 2.0831, 1.8326 and 7.8592 mg/mL, respectively, whereas for the encapsulated system, the Km values were 3.1604, 2.1708 and 9.2791 mg/mL, respectively. The results showed encapsulation enzymes gave higher Km value than the free enzymes. Comparatively the encapsulated alpha-amylase was 1.5 times higher and the glucoamylase and cellulase were 1.18 times higher. This suggests that the affinity of encapsulated enzymes for substrate was lower which might be due to the diffusional limitation of the substrate and enzymes. Amongst the three in both systems, glucoamylase was determined to have highest affinity followed by alpha-amylase and cellulase enzymes.

Recovery of Residual Crude Palm Oil from the Empty Fruit Bunch Spikelets Using Environmentally Friendly Processes

The development of new, low-cost technology to increase the oil recovery in the palm oil mill especially from the palm oil wastes has been an important goal for the industry to increase OER. According to preliminary oil detection, the residual oil is mainly located on the surface of spikelet, about 73.73 ± 0.05% from total residual oil. The combined water-steam shows the best oil extraction process, indicating 82 ± 0.13% of oil may be removed from the EFB spikelet. Thus, this method is chemical free and environmentally friendly residual CPO recovery process using EFB.

Preparation and Characterization of Sg. Sayong Clay Material for Biocatalyst Immobilization

This study was conducted to characterize Sg. Sayong clay so that it can be applied as a supporting material for the immobilization of biocatalyst in the bioconversion of wastewater into biofuel. The clay sample was physically and chemically characterized using Nitrogen Adsorption, X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Fourier Transform Infrared Spectroscopy (FTIR), Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) and Field Emission Scanning Electron Microscopy (FESEM). The results obtained showed that the clay composed of SiO2 (57.4%), followed by Al2O3 (32.5%), K2O (4.9%), Fe2O3 (3.8%) and traces amount of Ca, Mg, Ma, and Ti. The results also showed the clay type was kaolinite with some presence of quartz, illite, montmorillonite and microcline. The clay was also successfully coated onto the wire-mesh and immobilized with biocatalyst for further bioconversion study.