Soh Kheang Loh

Pretreatment of empty fruit bunch from oil palm for fuel ethanol production and proposed biorefinery process

This study evaluates the effects of some pretreatment processes to improve the enzymatic hydrolysis of oil palm empty fruit bunch (EFB) for ethanol production. The experimental results show that the bisulfite pretreatment was practical for EFB pretreatment. Moreover, the optimum pretreatment conditions of the bisulfite pretreatment (180 °C, 30 min, 8% NaHSO3, 1% H2SO4) were identified. In the experiments, a biorefinery process of EFB was proposed to produce ethanol, xylose products, and lignosulfonates.

Conventional methods and emerging wastewater polishing technologies for palm oil mill effluent treatment: a review.

The Malaysian palm oil industry is a major revenue earner and the country is ranked as one of the largest producers in the world. However, growth of the industry is synonymous with a massive production of agro-industrial wastewater. As an environmental protection and public health concern, the highly polluting palm oil mill effluent (POME) has become a major attention-grabber. Hence, the industry is targeting for POME pollution abatement in order to promote a greener image of palm oil and to achieve sustainability. At present, most palm oil mills have adopted the ponding system for treatment. Due to the successful POME pollution abatement experiences, Malaysia is currently planning to revise the effluent quality standards towards a more stringent discharge limits. Hence, the current trend of POME research focuses on developing tertiary treatment or polishing systems for better effluent management. Biotechnologically-advanced POME tertiary (polishing) technologies as well as other physicochemical methods are gaining much attention as these processes are the key players to push the industry towards the goal of environmental sustainability. There are still ongoing treatment technologies being researched and the outcomes maybe available in a while. However, the research completed so far are compiled herein and reported for the first time to acquire a better perspective and insight on the subject with a view of meeting the new standards. To this end, the most feasible technology could be the combination of advanced biological processes (bioreactor systems) with extended aeration, followed by solids separation prior to discharge. Chemical dosing is favoured only if effluent of higher quality is anticipated.

Robust enzymatic hydrolysis of Formiline-pretreated oil palm empty fruit bunches (EFB) for efficient conversion of polysaccharide to sugars and ethanol.

Oil palm empty fruit bunch (EFB) was pretreated by Formiline process to overcome biomass recalcitrance and obtain hemicellulosic syrup and lignin. Higher formic acid concentration led to more lignin removal but also higher degree of cellulose formylation. Cellulose digestibility could be well recovered after deformylation with a small amount of lime. After digested by enzyme loading of 15 FPU+10 CBU/g solid for 48 h, the polysaccharide conversion could be over 90%. Simultaneous saccharification and fermentation (SSF) results demonstrated that ethanol concentration reached 83.6 g/L with approximate 85% of theoretic yield when performed at an initial dry solid consistency of 20%. A mass balance showed that via Formiline pretreatment 0.166 kg of ethanol could be produced from 1 kg of dry EFB with co-production of 0.14 kg of high-purity lignin and 5.26 kg hemicellulosic syrup containing 2.8% xylose. Formiline pretreatment thus can be employed as an entry for biorefining of EFB.

Bisulfite pretreatment changes the structure and properties of oil palm empty fruit bunch to improve enzymatic hydrolysis and bioethanol production.

Bisulfite pretreatment is a proven effective method for improving the enzymatic hydrolysis of empty fruit bunch (EFB) from oil palm for bioethanol production. In this study, we set out to determine the changes that occur in the structure and properties of EFB materials and fractions of hemicellulose and lignin during the bisulfite pretreatment process. The results showed that the crystallinity of cellulose in EFB increased after bisulfite pretreatment, whereas the EFB surface was damaged to various degrees. The orderly structure of EFB, which was maintained by hydrogen bonds, was destroyed by bisulfite pretreatment. Bisulfite pretreatment also hydrolyzed the glycosidic bonds of the xylan backbone of hemicellulose, thereby decreasing the molecular weight and shortening the xylan chains. The lignin fractions obtained from EFB and pretreated EFB were typically G-S lignin, and with low content of H units. Meanwhile, de-etherification occurred at the β-O-4 linkage, which was accompanied by polymerization and demethoxylation as a result of bisulfite pretreatment. The adsorption ability of cellulase differed for the various lignin fractions, and the water-soluble lignin fractions had higher adsorption capacity on cellulase than the milled wood lignin. In general, the changes in the structure and properties of EFB provided insight into the benefits of bisulfite pretreatment.

Prospect, Challenges and Opportunities on Biofuels in Malaysia

The R&D on biofuels in Malaysia was first commenced in 1980s and since then its commercialization progressed at a slow pace with many uncertainties. Until recently, it has gained much attention and popularity not just in Malaysia but in many parts of the world, mainly rooted in some advantages it has over fossil fuels. There are at least three different generations of biofuels, i.e. first-generation biofuels, second-generation biofuels and third-generation biofuels.

Fractionation of oil palm empty fruit bunch by bisulfite pretreatment for the production of bioethanol and high value products

In this work, fractionation of empty fruit bunch (EFB) by bisulfite pretreatment was studied for the production of bioethanol and high value products to achieve biorefinery of EFB. EFB was fractionated to solid and liquor components by bisulfite process. The solid components were used for bioethanol production by quasi-simultaneous saccharification and fermentation. The liquor components were then converted to furfural by hydrolysis with sulfuric acid. Preliminary results showed that the concentration of furfural was highest at 18.8g/L with 0.75% sulfuric acid and reaction time of 25min. The conversion of xylose to furfural was 82.5%. Furthermore, we attempted to fractionate the liquor into hemicellulose sugars and lignin by different methods for producing potential chemicals, such as xylose, xylooligosaccharide, and lignosulfonate. Our research showed that the combination of bisulfite pretreatment and resin separation could effectively fractionate EFB components to produce bioethanol and other high value chemicals.

A Weibull statistics-based lignocellulose saccharification model and a built-in parameter accurately predict lignocellulose hydrolysis performance

Renewable energy from lignocellulosic biomass has been deemed an alternative to depleting fossil fuels. In order to improve this technology, we aim to develop robust mathematical models for the enzymatic lignocellulose degradation process. By analyzing 96 groups of previously published and newly obtained lignocellulose saccharification results and fitting them to Weibull distribution, we discovered Weibull statistics can accurately predict lignocellulose saccharification data, regardless of the type of substrates, enzymes and saccharification conditions. A mathematical model for enzymatic lignocellulose degradation was subsequently constructed based on Weibull statistics. Further analysis of the mathematical structure of the model and experimental saccharification data showed the significance of the two parameters in this model. In particular, the λ value, defined the characteristic time, represents the overall performance of the saccharification system. This suggestion was further supported by statistical analysis of experimental saccharification data and analysis of the glucose production levels when λ and n values change. In conclusion, the constructed Weibull statistics-based model can accurately predict lignocellulose hydrolysis behavior and we can use the λ parameter to assess the overall performance of enzymatic lignocellulose degradation. Advantages and potential applications of the model and the λ value in saccharification performance assessment were discussed.

Production and physico-chemical characterization of biochar from palm kernel shell

As the world’s second largest producer and exporter of palm oil, Malaysia’s palm oil industry leaves behind huge amounts of biomass waste from its plantation and milling activities such as empty fruit bunch, palm kernel shell (PKS), palm frond and palm trunk. Generally, most of the waste generated is disposed of via open dumping, used as solid fuel in boilers, or used as fertilizers. To enhance the use of the abundant biomass generated by the oil palm industry in Malaysia, conversion of biomass to biochar could be a promising alternative. Biochar has the strength in improving long term soil productivity and capable of sequestering carbon in soils to reduce the emission of carbon dioxide to atmosphere. This research project aims to investigate and optimize the use of PKS for biochar production through slow pyrolysis by using the Biochar Experimenter’s Kit (BEK) from All Power Labs, California. PKS was pyrolyzed at 400 °C for an hour. Biochar and the pyrolysis by-products were then collected. The biochar wa...

Effect of spent bleaching earth based bio organic fertilizer on growth, yield and quality of eggplants under field condition

Spent bleaching earth (SBE) is a solid waste generated from the bleaching process in palm oil industry. This solid waste is currently disposed directly in landfills without treatment, causing severe water and air pollution. Recently, dumping of SBE in landfills or public disposal sites has been prohibited in most countries. Meanwhile, high costs associated with the large area of land needed for storage of the residue has lead to the interest in regenerate SBE. Thus, a recent novel approach has been carried out on the utilization of SBE in agriculture as an alternative method for disposal. In this study, a field experiment was conducted at an experimental plot in Plant House National University Malaysia to evaluate the effect of SBE on the growth and quality of eggplant. Growth and quality parameters of eggplant including total fruit yield, total biomass, macronutrients concentration of leaf were studied through close monitoring and assessment. Field trials conducted showed that SBE is effective in promoti...

POME Treatment Efficacy as Affected by Carrier Material Size in Micro-Bioreactor System

This paper presents the effect of different sizes of palm kernel shell (PKS) activated carbon as the carrier material in a micro-bioreactor system to treat the palm oil mill effluent (POME). Three different sizes of PKS activated carbon were used as the carrier material, i.e. 4.750 – 2.360 mm (large), 1.180 – 0.710 mm (average) and 0.425 – 0.300 mm (small). The systems were run for a total of 29 days under hydraulic retention time (HRT) of 24 hours. The performances of several effluent quality parameters of POME regarding the use of PKS activated carbon of different sizes were studied. PKS activated carbon with size 1.180 – 0.710 mm showed the highest removal performances for chemical oxygen demand (COD), ammoniacal-nitrogen (AN), and solids, with 41 %, 84.6 %, and 88 % of removal respectively. The system with PKS activated carbon of size 4.750 - 2.360 mm showed the highest performance in removing TP (45 %), while 1.180 – 0.710 mm size of PKS activated carbon showed the highest performance in removing TN (53 %). The system was also found to effectively reduce the effluent colour. In overall, the PKS activated carbon of size 1.180 – 0.710 mm showed the best results as a carrier material to be used in the micro-bioreactor system in treating POME compared to the other two sizes.