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• PHA (3.39 g L−1) and XG (1.77 g L−1) productions were individually optimized. • PHA (6.43 g L−1) and XG (1.98 g L−1) co-culture productions were accomplished. • Co-culture bioconversions of palm oil promoted higher PHA production. • X. campestris and C. necator synergism is dependent to the bioconversion conditions. • Polymers properties were altered due to the culture configurations. In the present study, mixed and axenic submerged cultures of Cupriavidus necator and Xanthomonas campestris were performed for simultaneous and individual PHA and XG productions using palm oil (Elaeis guineensis) as substrate. Rotational Central Compound Design (RCCD) was successfully used in the optimization of individual productions of PHA (3.39 g L−1, Mw = 692.6 kDa) and XG (1.77 g L−1, Mw = 36.6 × 105 kDa). Novel simultaneous production of PHA (6.43 g L−1, Mw = 629.2 kDa) and XG (1.98 g L−1, Mw = 25.0 × 105 kDa), executed in bacterial co-cultivation, revealed to be a successful strategy to increment polymer synthesis, especially PHA. XG bioconversions followed a general trend of lower production in co-culture. Culture configurations also altered polymers properties and characteristics. [ABSTRACT FROM AUTHOR]

Highlights • Palm kernel shell sorbs and retains heavy oil as high as 0.25 g/g. • The recycled heavy oil is in-situ converted to desired products. • The secondary reactions contribute to the increases in char and gas yields equally. • The resulting light bio-oil can be completely evaporated upon to 200 °C. • Production of 2-methylfuran is much enhanced during heavy oil recycling. Abstract This paper investigated pyrolysis of palm kernel shell in a proposed reactor, which is characterized by internal recycling of heavy oil between a heavy oil sorption zone and pyrolysis zone. The internal recycling of heavy oil favors conversion of heavy oil to char, gas, and light oil. Compared with the product distribution from the conventional pyrolysis without heavy oil recycling, the yields of char, gas, and GC/MS detectable organic compounds increase from 34.8, 15.2, and 9.8 wt%-(dry feedstock) to 38.5, 19.0, and 16.9 wt%-(dry feedstock), respectively, with the help of internal recycling of heavy oil. The increases in the char and gas yields are interestingly found to be nearly equivalent. Furthermore, the yields of acetic acid and phenol in the resulting bio-oil can be as high as 10.1 and 2.7 wt%-(dry feedstock), and the outputs of 2-methylfuran, 2,6-dimethoxyphenol, and H 2 are increased by around 37, 7, and 4 times, respectively. [ABSTRACT FROM AUTHOR]

This research investigated the removal of lead (Pb 2+ ) by a novel biochar derived from palm oil sludge (POS-char) by slow pyrolysis. Multistage optimizations with central composite design were carried out to firstly optimize pyrolysis parameters to produce the best POS-char for Pb 2+ removal and secondly to optimize adsorption conditions for the highest removal of Pb 2+ . The optimum pyrolysis parameters were nitrogen flowrate of 30 mL min −1 , heating rate of 10 °C min −1 , temperature of 500 °C and time of 30 min. The optimum Pb 2+ adsorption conditions were concentration of 200 mg L −1 , time of 60 min, dosage of 0.3 g and pH of 3.02. The various functional groups within POS-char played a vital role in Pb 2+ uptake. Regeneration was demonstrated to be feasible using hydrochloric acid. Adsorption equilibrium was best described by Freundlich model. At low concentration range, adsorption kinetic obeyed pseudo-first-order model, but at high concentration range, it followed pseudo-second-order model. Overall, the results highlighted that POS-char is an effective adsorbent for Pb 2+ removal. [ABSTRACT FROM AUTHOR]

This research investigated the potential of palm kernel shell (PKS), empty fruit bunch (EFB) and palm oil sludge (POS), abundantly available agricultural wastes, as feedstock for biochar production by slow pyrolysis (50 mL min −1 N 2 at 500 °C). Various characterization tests were performed to establish the thermochemical properties of the feedstocks and obtained biochars. PKS and EFB had higher lignin, volatiles, carbon and HHV, and lower ash than POS. The thermochemical conversion had enhanced the biofuel quality of PKS-char and EFB-char exhibiting increased HHV (26.18–27.50 MJ kg −1 ) and fixed carbon (53.78–59.92%), and decreased moisture (1.03–2.26%). The kinetics of pyrolysis were evaluated by thermogravimetry at different heating rates (10–40 °C). The activation energies determined by Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa models were similar, and comparable with literature data. The findings implied that PKS and EFB are very promising sources for biochars synthesis, and the obtained chars possessed significant biofuel potential. [ABSTRACT FROM AUTHOR]

Thermoliquefaction of palm oil fiber was investigated using supercritical ethanol as solvent. A semi-continuous laboratory scale unit was developed to investigate the effects of temperature (300–500 °C), heating rate (10–30 °C.min −1 ) and cracking time (10–30 min) on the conversion of biomass in bio-oil. The main advantage of the proposed process is that a pure solvent is pumping through the reactor that contains the biomass, dispensing the use of biomass slurries. The yield of bio-oil ranged from 56% to 84%, depending on the experimental conditions. It was observed that an increase in working temperature led to an increase in the bio-oil production. Cracking time and heating rate variation had not shown a considerable effect on the conversion of biomass. The chemical profiles of bio-oil determined by GC/MS, indicate that at low temperature mainly sugar derivatives are produced, while at higher temperatures alcohols and phenolic are the majority compounds of the bio-oil. [ABSTRACT FROM AUTHOR]

In this research we assess the feasibility of using palm oil agricultural refinery waste as a carbon source for the production of rhamnolipid biosurfactant through fermentation. The production and characterization of rhamnolipid produced by Pseudomonas aeruginosa PAO1 grown on palm fatty acid distillate (PFAD) under batch fermentation were investigated. Results show that P. aeruginosa PAO1 can grow and produce 0.43 g L −1 of rhamnolipid using PFAD as the sole carbon source. Identification of the biosurfactant product using mass spectrometry confirmed the presence of monorhamnolipid and dirhamnolipid. The rhamnolipid produced from PFAD were able to reduce surface tension to 29 mN m −1 with a critical micelle concentration (CMC) 420 mg L −1 and emulsify kerosene and sunflower oil, with an emulsion index up to 30%. Results demonstrate that PFAD could be used as a low-cost substrate for rhamnolipid production, utilizing and transforming it into a value added biosurfactant product. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effective production of valuable PHA from palm oil and derived wastewater. • Achieving high PHA content of 30.5 wt% and volumetric yield of 0.372 g COD/g COD. • Secondary utilization of residual carbon saved 42.7% feedstock consumption. • Supplementing to initial carbon concentration strategy shortened synthesis time. • Promoting sludge concentration and particle size can increase PHA production. The potential of palm oil and derived wastewater pretreated by enzyme as co-substrates to accumulate polyhydroxyalkanoate (PHA) rich in short and medium-chain-length monomers under two feeding strategies was evaluated batchwise through mixed microbial cultures (MMCs) in activated sludge. A terpolymer with the maximum PHA content of 30.5 wt%, volumetric yield of 0.372 g COD/g COD and composition of ca. 84.7 ∼ 97.4/0.5 ∼ 1.6/2.1 ∼ 13.7 (3-hydroxybutyrate/ 3-hydroxyvalerate/ 3-hydroxyoctanoate, %) was achieved as a result of co-substrate incorporation. From the perspective of economic benefits, PHA accumulated via adopting strategy of supplementing carbon source to the same initial concentration per cycle saved 42.7 % of carbon consumption, along with a reduction in culture time (72 h). The above discoveries signify that the combination of palm oil and derived wastewater plus MMCs provides an alternative to the plastics industries for a more sustainable and efficient utilization of biological resources and an economic PHA accumulation approach. [ABSTRACT FROM AUTHOR]

A novel process for simultaneous production of furfural and pretreatment of oil palm empty fruit bunch (EFB) by dilute acid pre-hydrolysis was developed based on non-isothermal kinetic modeling. Mass transfer analysis suggested that the internal diffusion could be neglected as diffusion time of sulfuric acid in EFB particles was significantly shorter than the pre-hydrolysis period, whereas the heating stage could not be neglected due to a significant part of xylan was solubilized at the stage. A strategy for increasing furfural yield was developed by intermittent discharging of steam, resulting in 71.4 % furfural yield. The pretreated solids showed good enzymatic digestibility. 136.3 g/L glucose corresponding to 81.6 % yield was obtained by high-solid loading hydrolysis. 95.4 g furfural and 212 g glucose could be obtained from 1 kg dry EFB. Therefore, non-isothermal effects on polysaccharide hydrolysis and pentose decomposition should be considered carefully for an efficient process design of EFB biorefining., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Lignocellulose is resistant to degradation and requires pretreatment before hydrolytic enzymes can release fermentable sugars. Sulfuric acid has been widely used for biomass pretreatment, but high amount of degradation products usually occurred when using this method. To enhance accessibility to cellulose, we studied the performances of several dilute organic acid pretreatments of sugarcane bagasse and oil palm empty fruit bunch fiber. The results revealed that pretreatment with maleic acid yields the highest xylose and glucose release among other organic acids. The effects of concentration, duration of heating and heating temperature were further studied. Dilute maleic acid 1 % (w/w) pretreatment at 180 °C was the key to its viability as a substitute for sulfuric acid. Moreover, maleic acid did not seem to highly promote the formation of either furfural or 5-HMF in the liquid hydrolysate after pretreatment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

An air-cathode MFC-adsorption hybrid system, made from earthen pot was designed and tested for simultaneous wastewater treatment and energy recovery. Such design had demonstrated superior characteristics of low internal resistance (29.3 Ω) and favor to low-cost, efficient wastewater treatment and power generation (55 mW/m 3 ) with average current of 2.13 ± 0.4 mA. The performance between MFC-adsorption hybrid system was compared to the standalone adsorption system and results had demonstrated great pollutants removals of the integrated system especially for chemical oxygen demand (COD), biochemical oxygen demand (BOD 3 ), total organic carbon (TOC), total volatile solids (TVS), ammoniacal nitrogen (NH 3 -N) and total nitrogen (TN) because such system combines the advantages of each individual unit. Besides the typical biological and electrochemical processes that happened in an MFC system, an additional physicochemical process from the activated carbon took place simultaneously in the MFC-adsorption hybrid system which would further improved on the wastewater quality. [ABSTRACT FROM AUTHOR]

The synthesis of fatty acid methyl ester (FAME) from the high- and low-acid-content feedstock of crude palm oil (CPO) and karanj oil (KO) was conducted over CaO–La 2 O 3 –Al 2 O 3 mixed-oxide catalyst. Various reaction parameters were investigated using a batch reactor to identify the best reaction condition that results in the highest FAME yield for each type of oil. The transesterification of CPO resulted in a 97.81% FAME yield with the process conditions of 170 °C reaction temperature, 15:1 DMC-to-CPO molar ratio, 180 min reaction time, and 10 wt.% catalyst loading. The transesterification of KO resulted in a 96.77% FAME yield with the conditions of 150 °C reaction temperature, 9:1 DMC-to-KO molar ratio, 180 min reaction time, and 5 wt.% catalyst loading. The properties of both products met the ASTM D6751 and EN 14214 standard requirements. The above results showed that the CaO–La 2 O 3 –Al 2 O 3 mixed-oxide catalyst was suitable for high- and low-acid-content vegetable oil. [ABSTRACT FROM AUTHOR]

This study investigated the improvement of biogas production from solid-state anaerobic digestion (SS-AD) of oil palm biomass by optimizing of total solids (TS) contents, feedstock to inoculum (F:I) ratios and carbon to nitrogen (C:N) ratios. Highest methane yield from EFB, OPF and OPT of 358, 280 and 324 m 3 CH 4 ton −1 VS, respectively, was achieved at TS content of 16%, C:N ratio of 30:1 and F:I ratio of 2:1. The main contribution to methane from biomass was the degradation of cellulose and hemicellulose. The highest methane production of 72 m 3 CH 4 ton −1 biomass was achieved from EFB. Bacteria community structure in SS-AD process of oil palm biomass was dominated by Ruminococcus sp. and Clostridium sp., while archaea community was dominated by Methanoculleus sp. Oil palm biomass has great potential for methane production via SS-AD. [ABSTRACT FROM AUTHOR]

The present study aims to evaluate the operating costs of biodiesel production using palm oil in a pilot-scale plant with a capacity of 20,000 L/day (850 L/batch). The production plant uses crude palm oil as a feedstock, and methanol in a molar ratio of 1:10. The process incorporated acid esterification, basic transesterification, and dry washing with absorbent powder. Production costs considered in the analysis were feedstock, supplies, labor, electricity, quality and maintenance; amounting to $3.75/gal ($0.99/L) for 2013. Feedstocks required for biodiesel production were among the highest costs, namely 72.6% of total production cost. Process efficiency to convert fatty acids to biodiesel was over 99% and generated a profit of $1.08/gal (i.e., >22% of the total income). According to sensitivity analyses, it is more economically viable for biodiesel production processes to use crude palm oil as a feedstock and take advantage of the byproducts such as glycerine and fertilizers. [ABSTRACT FROM AUTHOR]

The effect of inoculum sources on the anaerobic digestion of paragrass was investigated. Two types of sludge were used as the inoculums: an anaerobic sludge obtained from a domestic wastewater treatment plant (OS) and a sludge acclimated to fibrous substrates in raw palm oil mill effluent (AMC). Microbial activity assays showed that the AMC had hydrolytic and acetogenic activities two times greater than the activities of the OS. In addition, the production of methane from acetate by the AMC occurred without a lag phase, while it took 8 days for the OS to start producing methane from the same substrate. The biochemical methane potential after 80 days digestion was 316 ml STP/g VS added using the AMC, and 277 ml STP/g VS added using the OS. The methane potential of the paragrass was estimated to be 3337 Nm 3 CH 4 /ha a. [ABSTRACT FROM AUTHOR]

In this study, pyrolysis technique was utilized for converting palm oil sludge to value added materials: bio-oil (liquid fuel) and bio-char (soil amendment). The bio-oil yield obtained was 27.4 ± 1.7 wt.% having a heating value of 22.2 ± 3.7 MJ/kg and a negligible ash content of 0.23 ± 0.01 wt.%. The pH of bio-oil was in alkaline region. The bio-char yielded 49.9 ± 0.3 wt.%, which was further investigated for sorption efficiency by adsorbing metal (Cd 2+ ions) from water. The removal efficiency of Cd 2+ was 89.4 ± 2%, which was almost similar to the removal efficiency of a commercial activated carbon. The adsorption isotherm was well described by Langmuir model. Therefore, pyrolysis is proved as an efficient tool for palm oil sludge management, where the waste was converted into valuable products. [ABSTRACT FROM AUTHOR]

A high-rate continuous stirred tank reactor (CSTR) was used to produce biogas from raw palm oil mill effluent (POME) at 55 °C at a highest organic loading rate (OLR) of 19 g COD/l d. Physical and chemical pretreatments were not performed on the raw POME. In order to promote retention of suspended solids, the CSTR was installed with a deflector at its upper section. The average methane yield was 0.27 l/g COD, and the biogas production rate per reactor volume was 6.23 l/l d, and the tCOD removal efficiency was 82%. The hydrolysis rate of cellulose, hemicelluloses and lignin was 6.7, 3.0 and 1.9 g/d, respectively. The results of denaturing gradient gel electrophoresis (DGGE) suggested that the dominant hydrolytic bacteria responsible for the biodegradation of the palm fiber and residual oil were Clostridium sp., while the dominant methanogens were Methanothermobacter sp. [ABSTRACT FROM AUTHOR]

The biomethane potential and structural changes of the methanogenic community in a solid-state anaerobic digestion process co-digesting cattle slurry and empty fruit bunches were investigated under mesophilic (37 °C) and thermophilic (55 °C) conditions. Phylogenetic microarrays revealed the presence of two hydrogenotrophic genera ( Methanoculleus and Methanobrevibacter ) and one acetoclastic genus ( Methanosarcina ). Methanosarcina numbers were found to increase in both mesophilic and thermophilic treatments of empty fruit bunches. Methanobrevibacter , which dominated in the cattle slurry, remained constant during anaerobic digestion (AD) at 37 °C and decreased in numbers during digestion at 55 °C. Numbers of Methanoculleus remained constant at 37 °C and increased during the thermophilic digestion. Physicochemical data revealed non-critical concentrations for important monitoring parameters such as total ammonia nitrogen, free ammonia nitrogen and volatile fatty acids in all treatments after AD. The biomethane potential of empty fruit bunches was higher under thermophilic conditions than under mesophilic conditions. [ABSTRACT FROM AUTHOR]

In this study, waste ostrich eggshell-derived calcium oxide ( denoted as CaO ( OE )) particles were synthesized and explored as cost-effective catalysts for the ultrasonic-assisted transesterification of palm oil. The physicochemical properties of the resultant catalysts were characterized by XRD, N 2 adsorption, XRF and Hammett indicator, while the catalytic activity was evaluated through transesterification of palm oil with methanol under ultrasonic conditions. More specifically, the CaO(OE) showed comparable catalytic activity to the one derived from commercial calcium carbonate ( denoted as CaO ( Lab )). Moreover, under ultrasonic conditions, the catalytic activity of CaO(OE) could be enhanced significantly. The maximum yield of fatty acid methyl esters could reach 92.7% under the optimal condition of reaction time of 60 min with ultrasonic power of 60% (120 W), methanol-to-oil ratio of 9:1, and catalyst loading of 8 wt.%. The results indicated that the CaO(OE) catalysts showed good catalytic performance and reusability, and may potentially reduce the cost of biodiesel production. [ABSTRACT FROM AUTHOR]

This study evaluated the potential of bioflocculant production from Aspergillus niger using palm oil mill effluent (POME) as carbon source. The bioflocculant named PM-5 produced by A. niger showed a good flocculating capability and flocculating rate of 76.8% to kaolin suspension could be achieved at 60 h of culture time. Glutamic acid was the most favorable nitrogen source for A. niger in bioflocculant production at pH 6 and temperature 35 °C. The chemical composition of purified PM-5 was mainly carbohydrate and protein with 66.8% and 31.4%, respectively. Results showed the novel bioflocculant (PM-5) had high potential to treat river water from colloids and 63% of turbidity removal with the present of Ca 2+ ion. [ABSTRACT FROM AUTHOR]

Highlights: [•] Catalytic hydrotreating of palm oil to bio-hydrogenated diesel over NiMoS2/Al2O3. [•] Optimized reaction conditions (temperature, pressure, LHSV, and H2/oil ratio). [•] Three major pathways of hydrodeoxygenation, decarboxylation and decarbonylation. [•] Major contribution of 65–80% from hydrodeoxygenation. [•] Isomerization and cracking as minor pathways above 360°C. [ABSTRACT FROM AUTHOR]

Highlights: [•] A series of CaO-loaded unimodal and bimodal porous silica catalysts were prepared. [•] Basicity increased with increasing the amount of CaO content. [•] The presence of macropores enhanced the accessibility of CaO inside the pellet. [•] Bimodal catalyst exhibited a high %FAME with excellent regeneration efficiency. [ABSTRACT FROM AUTHOR]

Highlights: [•] Biodiesel was produced enzymatically from a low-cost sludge palm oil and ethanol. [•] Locally-produced Candida cylindracea lipase from POME fermentation was applied. [•] The mixture of ethanol and tert-butanol increased the yield of biodiesel. [•] The lipase favours esterification than transesterification reaction. [Copyright &y& Elsevier]

Highlights: [•] Lactobacillus diolivorans efficiently converts crude glycerol to 1,3-propanediol. [•] L. diolivorans is not inhibited by 0.7g/l furfural and 0.3g/l 5-HMF. [•] Conversion of biobased resources to up to 85g/l with a productivity of 0.45g/lh. [ABSTRACT FROM AUTHOR]

Biodiesel is a promising alternating environmentally benign fuel to mineral diesel. For the development of easier transesterification process, stable and active heterogeneous mixed metal oxide of TiO 2 –ZnO and ZnO nanocatalysts were synthesized and exploited for the palm oil transesterification process. The synthesized catalysts were characterized by XRD, FT-IR, and FE-SEM studies for their structural and morphological characteristics. It was found that TiO 2 –ZnO nanocatalyst exhibits good catalytic activity and the catalytic performance was greatly depends on (i) catalyst concentration (ii) methanol to oil molar ratio (iii) reaction temperature and (iv) reaction time. A highest 98% of conversion was obtained at the optimum reaction parameters with 200 mg of catalyst loading and the biodiesel was analyzed by TLC and 1 H NMR techniques. The TiO 2 –ZnO nanocatalyst shows good catalytic performance over the ZnO catalyst, which could be a potential candidate for the large-scale biodiesel production from palm oil at the reduced temperature and time. [ABSTRACT FROM AUTHOR]

Residual oil in palm oil mill effluent (POME) poses difficulties in its treatment chain. Non-ionic surfactants containing different hydrophobic tail structures and their optimal concentrations were evaluated for effectiveness in biohydrogen production. By adding the surfactants at their critical micelle concentration in synthetic oily wastewater, the maximal H 2 yield was increased by 2.2 and 3.5 times for Triton X-100 and Tergitol 15-S-9, respectively, compared to the control. Using real POME, the supplemental Tergitol 15-S-9 resulted in a 56.4 % improvement in H 2 production. For continuous digestion studies, pure POME and Tergitol 15-S-9 supplemented POME (sPOME) were fed to thermophilic anaerobic sequencing batch reactors (ASBRs) under hydraulic retention time (HRT) of 32-12.5 days. Optimally at HRT 19 days, H 2 content in the biogas from sPOME-fed ASBR was noticeably higher, which gave a superior yield of 203.4 mLH 2 /gCOD removed (+15 %)., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Abstract: Combined system of high-rate anaerobic reactors for treating palm oil mill effluent (POME) was developed and investigated in this study. The system composed of one common primary hybrid reactor which was shared by two different secondary filter reactors. An overall COD removal efficiency of 93.5% was achieved in both systems. The secondary reactors contributed not only in enhancing the COD removal efficiency, but also ensured the performance stability of the entire system. Biomass remained intact in the secondary reactor in contrast to the primary reactor in which occasional washout of biomass was observed. The pH of POME was adjusted at the beginning of the operation, as the process continued POME did not require the external pH adjustment as the pH was maintained in desired range. The biogas was produced up to 110l/d with the yield of 0.171–0.269l [CH4]/g [COD removed] and 59.5–78.2% content of methane. [Copyright &y& Elsevier]

Abstract: Novel heterogeneous catalysts from calcium oxide (CaO)/calcined calcium carbonate (CaCO3) loaded onto different palm oil mill boiler ashes were synthesised and used in the transesterification of crude palm oil (CPO) with methanol to yield biodiesel. Catalyst preparation parameters including the type of ash support, the weight percentage of CaO and calcined CaCO3 loadings, as well as the calcination temperature of CaCO3 were optimised. The catalyst prepared by loading of 15wt% calcined CaCO3 at a fixed temperature of 800°C on fly ash exhibited a maximum oil conversion of 94.48%. Thermogravimetric analysis (TGA) revealed that the CaCO3 was transformed into CaO at 770°C and interacted well with the ash support, whereas rich CaO, Al2O3 and SiO2 were identified in the composition using X-ray diffraction (XRD). The fine morphology size (<5μm) and high surface area (1.719m2/g) of the fly ash-based catalyst rendered it the highest catalytic activity. [Copyright &y& Elsevier]

Abstract: High PHA production and storage using palm oil mill effluent (POME) was investigated using a laboratory batch Bio-PORec® system under aerobic-feeding conditions. Results showed that maximum PHA was obtained at a specific rate (q p) of 0.343C-mol/C-molh when air was supplied at 20ml/min. The PHA yield was found to be 0.80C-mol/C-mol acetic acid (HAc) at microaerophilic condition and the mass balance calculation showed that PHA production increased up to 15.68±2.15C-mmol/cycle. The experiments showed that short feeding rate, limited requirements for electron acceptors (e.g. O2, NO3) and nutrients (N and P) showed lower tendency of glycogen accumulation and contributed more to PHA productivity. [Copyright &y& Elsevier]

Abstract: A recent life cycle assessment (LCA) reported that biodiesel production in supercritical alcohols (SCA) produces a higher environmental load than the homogeneous catalytic process because an enormous amount of energy is required to recover excess alcohol. However, the excess alcohol could be dramatically reduced by increasing the operating temperature to 400°C; although the product would have to be considered as an alternative biofuel instead of biodiesel. A comparative LCA of the biodiesel production in two SCA at 300°C (C-SCA) and novel biofuel production in the same two SCA at 400°C (N-SCA) is presented. It was clear that the N-SCA process produces a dramatically reduced environmental load over that of the C-SCA process due to a lower amount of excess alcohol being used. The N-SCA process could be improved in terms of its environmental impact by changing from fossil fuel to biomass-based fuels for the steam generation. [Copyright &y& Elsevier]

Abstract: Waste animal bones was employed as a cost effective catalyst for the transesterification of palm oil. The catalyst was calcined at different temperatures to transform the calcium phosphate in the bones to hydroxyapatite and 800°C was found to give the best yield of biodiesel. The catalyst was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometry (EDS) and Fourier transform infrared spectrometry (FT-IR). Under the optimal reaction conditions of 20wt.% of catalyst, 1:18 oil to methanol molar ratio, 200rpm of stirring of reactants and at a temperature of 65°C, the methyl ester conversion was 96.78% and it was achieved in 4h. The catalyst performed equally well as the laboratory-grade CaO. Animal bone is therefore a useful raw material for the production of a cheap catalyst for transesterification. [Copyright &y& Elsevier]

Abstract: The present study reports the synthesis of gold nanoparticles (AuNps) from gold precursor using palm oil mill effluent (POME) without adding external surfactant, capping agent or template. The biosynthesized AuNps were characterized by using UV–vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). According to the image analysis performed on a representative TEM micrograph by counting 258 particles, the obtained AuNps are predominantly spherical with an average size of 18.75±5.96nm. In addition, some triangular and hexagonal nanoparticles were also observed. The influence of various reaction parameters such as reaction pH, concentration of gold precursor and interaction time to the morphology and size of biosynthesized AuNps was investigated. This study shows the feasibility of using agro waste material for the biosynthesis of AuNps which is potentially more scalable and economic due to its lower cost. [Copyright &y& Elsevier]

Abstract: Ultimate and proximate analyses and thermal degradation of bio-oils from pinewood and palm empty fruit bunches (PEFB) were carried out to evaluate the oils’ potential for production of fuels for transport, heat and power generation, and of hydrogen via the calculation of performance indicators. The pinewood and PEFB oils indicated good theoretical hydrogen yields of 13.7 and 15.9wt.% via steam reforming, but their hydrogen to carbon effective ratios were close to zero, and their propensity for fouling and slagging heat exchanger surfaces via combustion was high. Both oils exhibited two phases during mass loss under nitrogen flow at heating rates of 3–9Kmin−1, but the kinetics of their thermal degradation from TGA-FTIR analysis indicated different degradation mechanisms that were well reproduced by a nth order reaction model for pinewood and Jander’s 3D-diffusion model for PEFB. These findings lead to recommendations on pretreatments prior to the oils’ utilisation. [Copyright &y& Elsevier]

Abstract: This study identifies the potential greenhouse gas (GHG) reductions, which can be achieved by optimizing the use of residues in the life cycle of palm oil derived biodiesel. This is done through compilation of data on existing and prospective treatment technologies as well as practical experiments on methane potentials from empty fruit bunches. Methane capture from the anaerobic digestion of palm oil mill effluent was found to result in the highest GHG reductions. Among the solid residues, energy extraction from shells was found to constitute the biggest GHG savings per ton of residue, whereas energy extraction from empty fruit bunches was found to be the most significant in the biodiesel production life cycle. All the studied waste treatment technologies performed significantly better than the conventional practices and with dedicated efforts of optimized use in the palm oil industry, the production of palm oil derived biodiesel can be almost carbon neutral. [Copyright &y& Elsevier]

Abstract: In this paper, the kinetics of palm oil ethanolysis with various models have been investigated in a temperature range of 25–55°C. The highest yield was achieved when the conversion to ethyl ester was 97.5±0.5% in the stated temperature range, using ethanol:oil molar ratio of 12:1, and 1.0wt.% sodium ethoxide. The level of conformity of the reaction with reversible second order, irreversible second order and first order kinetic models were evaluated by means of the R 2 values of the linear curves. The ethanolysis showed the best conformity with irreversible second order kinetic model with 92–98% level of confidence. The reaction rate constants were within 0.018–0.088dm3/molmin and the activation energy of the reaction was 42.36kJ/mol. [Copyright &y& Elsevier]

Abstract: Fatty acid methyl esters (FAME) were produced from palm oil using eggshell modified with magnesium and potassium nitrates to form a composite, low-cost heterogeneous catalyst for transesterification. The catalyst, prepared by the combination of impregnation/co-precipitation was calcined at 830°C for 4h. Transesterification was conducted at a constant temperature of 65°C in a batch reactor. Design of experiment (DOE) was used to optimize the reaction parameters, and the conditions that gave highest yield of FAME (85.8%) was 5.35 wt.% catalyst loading at 4.5h with 16:1 methanol/oil molar ratio. The results revealed that eggshell, a solid waste, can be utilized as low-cost catalyst after modification with magnesium and potassium nitrates for biodiesel production. [Copyright &y& Elsevier]

Abstract: The potential of Mg x Co2− x O2 as heterogeneous reusable catalyst in transesterification of palm oil to methyl ester was investigated. The catalyst was prepared via co-precipitation of the metal hydroxides at different Mg–Co ratios. Mg1.7Co0.3O2 catalyst was more active than Mg0.3Co1.7O2 in the transesterification of palm oil with methanol. The catalysts calcined at temperature 300°C for 4h resulted in highly active oxides and the highest transesterification of 90% was achieved at methanol/oil molar ratio of 9:1, catalyst loading of 5.00wt.%, reaction temperature of 150°C and reaction time of 2h. The catalyst could easily be removed from reaction mixture, but showed 50% decrease in activity when reused due to leaching of active sites. [Copyright &y& Elsevier]

Abstract: This work aims to demonstrate the enzymatic production of fatty acid ethyl ester biodiesel from highly acidic feedstock in a single-step reaction, without co-solvents and avoiding the inhibition of the enzyme by ethanol and glycerol. Additionally, an empirical equation is proposed to predict the kinetics of the production reaction as a function of the used feedstock and catalyst concentration. Biodiesel production from highly acidic feedstock perform via simultaneous esterification of free fatty acids and transesterification of triacylglycerols. Enzymatic catalysis is one of the most promising alternative technologies for the biodiesel production. Increasing of the enzymatic bioactivity is crucial for the success of such process in industrial scale. Currently, stepwise addition of the alcohol or the use of co-solvents have been proposed to avoid enzyme inhibition, such strategies add downstream processes to the production. These results can be applied to the development economical-viable enzymatic production of biodiesel in industrial scale. [Copyright &y& Elsevier]