Mohd Noriznan Mokhtar

Renewable sugars from oil palm frond juice as an alternative novel fermentation feedstock for value-added products.

In this paper, we report that pressed juice from oil palm frond (OPF) contained renewable sugars such as glucose, sucrose and fructose. By using a simple sugarcane press, 50% (wt/wt) of OPF juice was obtained from fresh OPF. The glucose content in the juice was 53.95±2.86g/l, which accounts for 70% of the total free sugars. We have examined the effect of various OPF juice concentrations on the production of poly(3-hydroxybutyrate), P(3HB) by Cupriavidus necator CCUG 52238(T). The cell dry mass in shake flask experiment reached 8.42g/l, with 32wt.% of P(3HB) at 30% (v/v) of OPF juice, comparable with using technical grade sugars. The biopolymer had a molecular mass, M(w) of 812kDa, with a low polydispersity index of 1.61. This result indicates that OPF juice can be used as an alternative renewable carbon source for P(3HB) production and has potential as a renewable carbon source.

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.

Xylitol Biological Production: A Review of Recent Studies

Xylitol is an alternative sweetener that is recommended for use in food and pharmaceutical products, as it has some health benefits. It is currently produced on a large scale using a chemical reduction that requires high energy and is costly. Biological conversion of xylitol using microorganisms is an alternative process that is environmentally friendly and cost-effective. This process has been studied in an effort to provide one that is high yielding and competitive with chemical processes. This article reviews recent studies in the development of biological conversion processes for the production of xylitol, including biomass conversion, fermenting microorganisms, and new technology for full-scale process development.

Extractive bioconversion of cyclodextrins by Bacillus cereus cyclodextrin glycosyltransferase in aqueous two-phase system

An extractive bioconversion with Bacillus cereus cyclodextrin glycosyltransferase (CGTase, EC 2.4.1.19) in aqueous two-phase system (ATPS) was investigated for the synthesis and recovery of cyclodextrins (CDs). Optimum condition for the extractive bioconversion of CDs was achieved in ATPS consisted of 7.7% (w/w) polyethylene glycol (PEG) 20,000 and 10.3% (w/w) dextran T500 with volume ratio (VR) of 4.0. Enzymatic conversion of starch occurred mainly in dextran-rich bottom phase whereas the product, CDs was transferred to top phase and a higher partition coefficient of CDs was achieved. Repetitive batch of CDs synthesis was employed by replenishment of the top phase components and addition of starch every 8h. An average total CDs concentration of 13.7 mg/mL, (4.77 mg/mLα-CD, 5.02 mg/mLβ-CD and 3.91 mg/mLγ-CD) was recovered in the top phase of PEG 20,000/dextran T500 ATPS. This study showed the effectiveness of ATPS application in extractive bioconversion of CDs synthesis with B. cereus CGTase.

Comparative Analyses of Response Surface Methodology and Artificial Neural Network on Medium Optimization for Tetraselmis sp. FTC209 Grown under Mixotrophic Condition

Mixotrophic metabolism was evaluated as an option to augment the growth and lipid production of marine microalga Tetraselmis sp. FTC 209. In this study, a five-level three-factor central composite design (CCD) was implemented in order to enrich the W-30 algal growth medium. Response surface methodology (RSM) was employed to model the effect of three medium variables, that is, glucose (organic C source), NaNO3 (primary N source), and yeast extract (supplementary N, amino acids, and vitamins) on biomass concentration, X max, and lipid yield, P max/X max. RSM capability was also weighed against an artificial neural network (ANN) approach for predicting a composition that would result in maximum lipid productivity, Prlipid. A quadratic regression from RSM and a Levenberg-Marquardt trained ANN network composed of 10 hidden neurons eventually produced comparable results, albeit ANN formulation was observed to yield higher values of response outputs. Finalized glucose (24.05 g/L), NaNO3 (4.70 g/L), and yeast extract (0.93 g/L) concentration, affected an increase of X max to 12.38 g/L and lipid a accumulation of 195.77 mg/g dcw. This contributed to a lipid productivity of 173.11 mg/L per day in the course of two-week cultivation.

Factors Affecting Poly(3-hydroxybutyrate) Production from Oil Palm Frond Juice by Cupriavidus necator (CCUG52238T)

Factors influencing poly(3-hydroxybutyrate) P(3HB) production by  Cupriavidus necator  CCUG52238T utilizing oil palm frond (OPF) juice were clarified in this study. Effects of initial medium pH, agitation speed, and ammonium sulfate (NH4)2SO4 concentration on the production of P(3HB) were investigated in shake flasks experiments using OPF juice as the sole carbon source. The highest P(3HB) content was recorded at pH 7.0, agitation speed of 220 rpm, and (NH4)2SO4 concentration at 0.5 g/L. By culturing the wild-type strain of C. necator under the aforementioned conditions, the cell dry weight (CDW) and P(3HB) content obtained were 9.31 ± 0.13 g/L and 45 ± 1.5 wt.%, respectively. This accounted for 40% increment of P(3HB) content compared to the nonoptimized condition. In the meanwhile, the effect of dissolved oxygen tension (DOT) on P(3HB) production was investigated in a 2-L bioreactor. Highest CDW (11.37 g/L) and P(3HB) content (44 wt.%) were achieved when DOT level was set at 30%. P(3HB) produced from OPF juice had a tensile strength of 40 MPa and elongation at break of 8% demonstrated that P(3HB) produced from renewable and cheap carbon source is comparable to those produced from commercial substrate.

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.

Effects of bulking agents, load size or starter cultures in kitchen-waste composting

BackgroundTo prevent the interruption of the carbon cycle by the disposal of waste to landfills, organic kitchen waste requires proper treatment such as composting to reduce its uncontrolled degradation on disposal sites and subsequent greenhouse gases, odour emissions and nutrient losses. This study investigated the effects of bulking agent, newspaper and onion peels, composting waste load sizes of 2 and 6 kg, or the use of starter culture on kitchen-waste composting consisting of nitrogen-riched substrates, vegetable scraps and fish processing waste in an in-vessel system. The optimised formulation of kitchen waste mixture was used for a 30-day composting study, where the temperature profiles were recorded and the carbon-to-nitrogen ratios were measured as an indication of compost maturity. The kitchen-waste composting process was conducted in parallel in two fabricated kitchen waste composters.ResultsIt was found that the onion peels were more suitable in producing matured compost where the carbon-to-nitrogen ratio reduced to 10 within 16 days of composting. A smaller kitchen waste load size of 2 kg gave a shorter composting time by half when compared to the 6 kg. The use of a microbial cocktail consisting seven types of bacteria and eight types of fungi isolated from soils as a starter culture for this kitchen-waste composting did not show advantages in accelerating the composting process.ConclusionsThe results suggest that the in-vessel kitchen-waste composting can be efficient with a minimal load of about 2 kg using onion peels without additional starter culture.

Immobilisation of cyclodextrin glucanotransferase into polyvinyl alcohol (PVA) nanofibres via electrospinning

Highlights • Fabrication of enzyme-carrying polymeric nanofibers by electrospinning.• PVA nanofibers structure and size were not affected by the addition of enzyme.• The electrospun CGTase/PVA nanofibers show excellent immobilisation efficiency.

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.