Category Archives: 2017 Vol 29 March

A REVIEW OF MODELS FOR ASSESSING CARBON STOCKS AND CARBON SEQUESTRATION IN OIL PALM PLANTATIONS

Reliable estimates of the carbon present in stands of oil palm, both in the palms themselves and in other biomass components of oil palm plantations, are crucial for assessing the net greenhouse gas (GHG) balance and carbon footprint of palm oil production. Carbon sequestered during the growth of the oil palm crop generally represents the largest item of the oil palm GHG budget, being second in magnitude only to land use change (LUC) or, for crops grown on peat soil, to microbial peat oxidation. In this article, alternative models available for assessing carbon stocks and carbon sequestration in oil palm plantations are examined taking into account factors such as palm age, planting density and soil type. Both linear and non-linear models are discussed and the crop and plantation components contributing to them are reviewed, as is the methodology used, which may involve destructive or non-destructive techniques, or a combination of both. Guidance is given for selecting the most appropriate model.

STATISTICAL GUIDELINES FOR COMPARING COMMERCIAL OIL PALM VARIETIES

Samples of 42 dura x pisifera progenies of Ekona, AVROS, Ghana and Nigeria oil palm varieties, each involving six pisifera, were used to determine the minimum sample size of their parents for obtaining statistical yield differences between varieties. The 95% confidence interval of differences between varieties decreased sharply and, hence, the precision of the test improved, when increasing the number of progenies from 6 to 30 and pisifera (involved) from 1 to 4 and then levelled off to a steady decrement. As a test of differences the confidence interval has only a power of 50%, being the probability that a false null hypothesis of zero difference between varieties is rejected. With a power of 80%, a sample of 60 progenies in three replications detects, depending on the variance of the pisifera parents, a significant yield difference of 4.5% between Nigeria and AVROS and 7% between Ghana and Ekona with 6 and 9 pisifera in the sample, respectively. The article argues to incorporate optimal planting density as a crucial trait in selecting oil palm varieties. This study offers a method to obtain unbiased progeny samples, along with a field lay out for bulk recording of progeny plots.

DIFFERENTIAL EXPRESSION ANALYSIS OF OIL PALM FATTY ACID BIOSYNTHETIC ENZYMES WITH GEL-FREE QUANTITATIVE PROTEOMICS

The control mechanisms of de novo fatty acid biosynthesis continue to intrigue, particularly at protein level. The cross talk between transcriptional and metabolic regulatory networks remains undefined. In order to understand the metabolic factors affecting oleic acid biosynthesis in Elaeis guineensis var. tenera (oil palm), two-dimensional liquid chromatography-tandem mass spectrometry (2DLC-MS/MS) was attempted to capture the main fatty acid biosynthetic enzymes involved in oleic acid production. These enzymes were extracted from the chromoplast of low and high oleic mesocarps of 20th week after anthesis. Chromoplast proteins were separated using offline 2DLC for mass spectrometric analysis. Two subunits of acetyl-CoA carboxylase, β-ketoacyl-acyl carrier protein (ACP) reductase, β-hydroxyacyl-ACP dehydrogenase, 3-enoyl- ACP reductase, β-ketoacyl-ACP synthase and stearoyl-ACP desaturase were identified. The relative expression of these fatty acid biosynthetic enzymes was determined using isobaric tags labelling. Initial assessment revealed that β-hydroxyacyl-ACP dehydrogenase and β-ketoacyl-ACP synthase were present in a higher abundance in the high oleic acid mesocarps while the accumulation of 3-enoyl-ACP reductase was lower relative to the other fatty acid biosynthetic enzymes investigated. The existence of other differentially expressed metabolic enzymes suggests that the control mechanism of fatty acid production, in particular oleic acid, might involve more than just the main fatty acid biosynthetic enzymes.

GENETIC VARIATION OF ENTOMOPATHOGENIC FUNGI, Metarhizium anisopliae AND Isaria amoenerosea AND THEIR PATHOGENICITY AGAINST SUBTERRANEAN TERMITE, Coptotermes curvignathus

This study determined the genetic similarity of 22 isolates of Metarhizium anisopliae and 51 isolates of Isaria amoenerosea isolated from mineral and peat soils, involving random amplified polymorphic DNA (RAPD) and using polymerase chain reaction (PCR) technology. The pathogenicity of the selected isolates from both genera of fungi were then tested against the subterranean termites, Coptotermes curvignathus. The RAPD-PCR analysis revealed high genetic similarity within the isolates of M. anisopliae and I. amoenerosea, at the similarity ranging from 52% to 100%. For M. anisopliae, the fungal isolates were grouped into two main clusters and the isolates of I. amoenerosea were separated into five main clusters. Within clusters in each species, there was little evidence on high similarity within isolates from the same soil type, but most of fungal isolates were well distributed within the clusters. Based on the bioassay data, the isolates of M. anisopliae were more pathogenic on termites, as compared to the isolates of I. amoenerosea. The isolates of M. anisopliae caused high percentage of infections, ranging from 71% to 84% at 15 days after treatment (DAT), and the isolate of M11H was the most pathogenic against termites with the LT50 value of 6.36 days. For isolates of I. amoenerosea, the percentage of infection were low, ranging from only 5% to 31%. This laboratory study showed that M. anisopliae has a potential to be used to control termites, as it has rapid infecting capability. However, further studies should be conducted to confirm the effectiveness of the M. anisopliae to control termites, especially in the field.

CONTROLLING Metisa plana Walker (Lepidoptera: Psychidae) OUTBREAK USING Bacillus thuringiensis AT AN OIL PALM PLANTATION IN SLIM RIVER, PERAK, MALAYSIA

Aerial spraying of Bacillus thuringiensis (Bt)-based biopesticides, Ecobac-1 (EC) was carried out at an oil palm plantation in Slim River, Perak, Malaysia to control the outbreak of bagworm, Metisa plana. Close monitoring of bagworm census, precise timing and follow-up aerial spraying of Ecobac-1 (EC) were important strategies for controlling the multi-stage bagworm outbreak. The first aerial spraying of Ecobac-1 (EC) which was conducted on 11 October 2013 had successfully reduced the first generation larvae population from 187.1 larvae per frond (LPF) eight days prior to treatment to 77.6 LPF at 14 days after treatment (DAT), indicating 56.0% reduction in bagworm population. The second aerial spraying of Ecobac-1 (EC) undertaken on 19 December 2013, had reduced the second generation larvae population from 358.7 LPF a day prior to treatment to 105.2 LPF at 14 DAT, which resulted in 70.7% reduction in bagworm population. Whilst the third aerial spraying done on 7 March 2014 had further reduced the population from 51.3 LPF three days prior to treatment to 17.2 LPF at 14 DAT, indicated a 66.4% reduction. The three consecutive aerial spraying of Ecobac-1 (EC) to control the three generations of M. plana at an oil palm plantation in Slim River, Perak successfully reduced the overall bagworm population by 90.8%. Therefore, it is recommended for the management to conduct a constant vigilance and census for successive control of bagworm population below the economic threshold level.

EFFICACY OF PHEROMONE TRAPPING AND AERIAL SPRAYING OF Bacillus thuringiensis (Bt) FOR CONTROLLING BAGWORM, Metisa plana WALKER (Lepidoptera: Psychidae) IN YONG PENG, JOHOR, MALAYSIA

Recurring bagworm outbreak is a major problem in the oil palm plantation. The continuous use of chemical insecticides to control bagworm outbreaks, the lack of beneficial plants in the plantation to attract natural enemies, and infestation in neighbouring plantations were reported as the contributing factors for bagworm outbreaks. Hence, the aim of this study is to evaluate the efficacy of pheromone trapping application for controlling bagworm, Metisa plana in Mukim Chaah smallholdings in Yong Peng, Johor, Malaysia. The installation of pheromone traps at Mukim Chaah smallholdings was carried out at four different locations for two consecutive generations of M. plana. Results showed that the first and second generations of pheromone trapping at Kg Sg Berlian and Kg Sawah Padi, without the aerial spraying of Bacillus thuringiensis (Bt) have successfully reduced 89% and 77% of bagworm population, respectively. Meanwhile, another trapping session conducted at Kg Temehel and Kg Seri Sepakat, together with the aerial spraying of Bt, resulted in the first and second generations of pheromone trapping to successfully reduced 94% and 85% of bagworm population, respectively. Together with the aerial spraying of Bt, the two consecutive generations of pheromone trapping application at two different areas in Mukim Chaah smallholdings successfully reduced bagworm population to manageable levels

CHARACTERISATION OF RHIZOPHORA PARTICLEBOARD USING BIO-OIL-BASED PHENOL FORMALDEHYDE (PF) RESIN

Phenol formaldehyde (PF) resin has been extensively used in various branches of industry as adhesive especially in the production of wood-based panels. However, due to the use of expensive and limited petroleum-based phenol in its formulation, there is a strong interest to explore renewable biomass material to partially substitute the phenol. In this work, slow pyrolysis was used to convert oil palm frond into bio-oil. From there, the phenol-rich fraction of the bio-oil was separated and added into the formulation of PF resin to produce an economical and environmental-friendly type of PF resin, known as bio-oil-phenol- formaldehyde (BPF) resin. Rhizophora particleboard was then fabricated with the BPF resin as adhesive. The particleboard was found to display excellent mechanical and physical properties with satisfactory formaldehyde emission. A morphological study of the particleboard also supported previous findings. The corresponding atomic number of the particleboard obtained from the morphological study was compared with those of water phantom and a fascinatingly favourable similarity was observed. This finding, hence, proposed a novel higher value-added application of the Rhizophora particleboard which has been largely researched as a potential phantom material in diagnostic radiography.

FERMENTATION OF BIODIESEL-DERIVED WASTE FOR 1,3-PROPANEDIOL PRODUCTION WITH RESPONSE SURFACE METHODOLOGY

The present study aimed to investigate the fermentation conditions favouring the maximum production of 1,3-propanediol (1,3-PD) from crude glycerol. Response surface methodology (RSM) based on central composite design (CCD) was applied in designing the experiments to evaluate the interactive effects of glycerol concentration (20 to 50 g litre-1), pH (6 to 8), temperature (30°C to 40°C) and incubation time (48 to 72 hr) on 1,3-PD production. A total of 30 experimental runs consisting of 16 factorial points, eight axial points and six centre points were conducted. It was found that the derived optimum conditions were: 39.9 g litre-1 glycerol; pH: 7.6, temperature: 33°C and incubation time: 59.1 hr. Under these conditions, the 1,3-PD produced (9.85 g litre-1) was ~2% higher than the predicted value by RSM (9.69 g litre-1), hence, the experimental design employed in validating the results obtained was significant. The analysis of variance (ANOVA) showed high coefficient of the determination values (R2) of 0.9444. The fermentation using RSM was able to increase the 1,3-PD production by two-fold.

ENZYMATIC SYNTHESIS OF STRUCTURED LIPID BASED ON SILKWORM OIL AND PALM OLEIN

The present study describes the synthesis and characterisation of structured lipid (SL) containing α-linolenic acid (ALA) prepared from palm olein (POo) and silkworm oils (SWO) employing enzymatic interesterification method. POo was chosen as one of the substrate because it does not contain ALA and is oxidatively more stable compared to other vegetable oils. The study was aimed to obtain an ALA content of about 10% in the structured lipid which was achieved with the blend of POo and SWO in the ratio of 80:20 (wt/wt). The reactions were catalysed by a sn-1, 3-regiospecific lipase, Lipozyme RM IM. The effect of reaction time, temperature were studied and were found to be at 4 hr and 65°C-70°C respectively at a lipase concentration 4% (w/w) of substrates. Physico-chemical characteristics of both the substrate oils were determined and compared with those of initial physical blends and the prepared SL. The oxidative stability of SL was also studied and the induction time was found to be at 13.2 hr which was higher with respect to SWO. The SL prepared using refined POo, SWO has potential applications in nutraceutical, food and industrial applications.

NON-CATALYTIC ONE-POT SYNTHESIS OF POLYHYDROXY ESTOLIDES FROM OLEIC ACID

Polyhydroxy estolides were successfully synthesised from oleic acid through a non-catalytic one-pot method. Gel permeation chromatography (GPC) analysis showed that the yield of the polyhydroxy estolides was about 72% and the number average molecular weight (Mn) of the product ranges between 1000 – 2200 Da. Other instrumental analyses such as nuclear magnetic resonance (NMR), Fourier transform infra- Red (FTIR) and Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) as well as acid value analysis revealed that the prepared polyhydroxy estolides was oligomers of dihydroxystearic acid linked by ester groups and further confirmation of the oligomers structure was achieved by reduction and saponification reactions.

CORROSION INHIBITION OF MILD STEEL IN HYDROCHLORIC ACID SOLUTION USING FATTY ACID DERIVATIVES

The inhibitive actions of fatty acid derivatives namely palmitate hydrazide (PH), N-ethylidene palmitate hydrazide (EPH) and N-phenylmethylidene palmitate hydrazide (PPH) on mild steel in 1 M hydrochloric acid were investigated using open circuit potential, linear polarisation and electrochemical impedance spectroscopy techniques. It was observed that the percentage of inhibition efficiency (η%) increased with increasing concentrations of inhibitor and temperature of test medium. The maximum η% approaches 85% in the presence of 200 mg litre-1 of inhibitors EPH and PPH at 308 ± 1K. The inhibitor efficiencies were found to be in the following order: PPH>EPH>PH. The adsorption of these inhibitors on mild steel surface obeys Langmuir adsorption isotherm. They act as mixed-type inhibitors. Scanning electron microscopy-energy dispersive X-ray (SEM-EDX) was also carried out on polished mild steel coupons and those immersed in the test medium with the absence and presence of 200 mg litre-1 of the inhibitors studied.

SYNTHESIS OF DIMERATE ESTERS BY SOLVENT-FREE METHOD

Dimerate ester is normally used as lubricant base stock. Herein, we highlighted the preparation of several C36 dimerate esters derived from C36 dimer acid and medium chain length alcohols, i.e. 1-octanol, 1-hexanol and 2-ethylhexanol without the need for either solvent or catalyst but drying agent, 3Å molecular sieve (3Å MS) having acid value as low as 0.06 mg KOH g-1 of sample. Optimisation of various reaction parameters such as temperature, molar ratio, reaction time and water removal set-up was also carried out. The most affecting factors in synthesising low acid value C36 dimerate ester are reaction temperature and efficiency of water removal. The esterification was carried out under optimum conditions by refluxing at 200°C for 24 hr using 1:4.5 molar ratio of C36 dimer acid/alcohol in the presence of 15% w/w of 3Å MS.

A CRADLE-TO-GATE STUDY OF GHG EMISSIONS FROM THE TRANSPORTATION OF PALM OIL, PALM OLEIN AND PALM STEARIN USING THE LIFE CYCLE ASSESSMENT APPROACH

This life cycle assessment (LCA) is a cradle-to-gate study of energy consumption and greenhouse gas (GHG) emissions in transportation of palm oil, palm olein and palm stearin along the palm oil supply chain. This includes the transportation of the oil palm pollinated bunches from the ‘mother palm’ to the seed laboratories, the germinated seeds to the nurseries, seedlings from nurseries to oil palm plantations, fresh fruit bunches (FFB) from plantations to mills, crude palm oil (CPO) from mills to refineries and refined, bleached and deodorised (RBD) palm oil (RBO PO) and its fractionated products namely RBD palm olein (RBD POo) and RBD palm stearin (RBO POs) from refineries/fractionation plants to ports and retailers. The objective of this study is to use the LCA approach to identify at which stage of the palm oil supply chain that transportation contributes the most to the environmental performance in terms of GHG emissions within the boundary of the study. The analysis of the LCI data for determining overall GHG emissions for the transportation along the oil palm supply chain, on the basis of the production of 1 t of the RBD PO, indicated that the transportation of FFB from plantation to mill and transportation of CPO from mill to refinery gave the highest GHG emissions. Based on the production of 1 t of the RBD PO, the GHG emissions during the transportation of FFB from plantation to mill and the transportation of CPO from mill to refinery were 21.94 kg CO2 eq. and 20.86 kg CO2 eq., respectively.

HYDROTHERMAL TREATMENT OF OIL PALM WOOD: EFFECT OF TREATMENT VARIABLES ON DIMENSIONAL STABILITY USING RESPONSE SURFACE METHODOLOGY

Oil palm wood (OPW) extracted from felled oil palm trunks during replanting could be a source of replenishment for the depleted timber sources. Nevertheless, dimensional instability of OPW is one of the drawbacks that need to be addressed before it can be utilised efficiently. Therefore, to improve its dimensional stability, hydrothermal treatment using different buffered media was employed in this study and the optimal treatment condition for OPW were investigated. Response surface methodology (RSM) models for treatment temperature, treatment duration and buffered media of hydrothermally treated OPW were developed. OPW samples were hydrothermally treated with different buffered media (pH 4 to pH 9), treatment temperature (60oC to 160oC) and time (13 min to 147 min). Water absorption (WA) and thickness swelling (TS) of the treated samples were determined. It is demonstrated that hydrothermal treatment has improved the dimensional stability of treated samples with treatment temperature appearing to be the most influential factor. Samples treated in an acidic media displayed lower WA mainly due to the fact that higher amount of hydrophilic hemicellulose was degraded under acidic condition. However, lower TS was observed in the samples treated in alkaline media, probably caused by the removal of lignin that increased the porosity of the OPW.