Microscopic observation of `Gaharu` wood from Aquilaria malaccensis

Aquilaria produces fragrant wood known as `Gaharu` in its stem and branches, often in mature and damaged trees. In this study, anatomical characteristics in juvenile and mature trees were investigated by comparing their anatomical structures after various staining methods and direct observations under a light microscope. Juvenile and mature wood share similar anatomical structures. No major differences were observed other than the percentage of area covered by included phloem in juvenile was 2.16 times more than that of the mature wood. Microscopic observation revealed that in mature resinous wood, brownish bodies were found in ray and axial parenchyma, included phloem, xylem vessels and fibres, and this finding indicates that these are important elements for `Gaharu` depositing. Thus, it was concluded that juvenile tree possess the anatomical features of that of mature wood in producing `Gaharu`

Chemical characterization of imperata cylindrical (`Lalang`) and pennisetum purpureum (Napier grass) for bioethanol production in Malaysia

Grass is a candidate biomass producer because it is fibrous and it thrives well on poor soils. The chemical properties of two grass species growing naturally and abundantly on idle lands in Malaysia were investigated in this study. The grasses selected were Imperata cylindrical (`Lalang`) and Pennisetum purpureum (Napier grass). For the purpose of analysis, Napier grass was further divided into male and female plants, and stem and leaves. Lignin, hemicellulose and cellulose contents were determined using the TAPPI standard methods. `Lalang` was found not to be an attractive biomass producer because of its high lignin content (22%) (P<0.05). On the contrary, Napier grass, particularly the female stem, had low lignin content (13%) (P<0.05) and a favourably high level of cellulose (46%) (P<0.05). In the female leaf, lignin content was higher (20.7%), while the cellulose content (30.4%) was lower compared to the stem. Although the cellulose content in the male stem (51%) was slightly higher (P<0.05) than the female, its lignin was two-fold above that of the female stem, making it a less desirable biomass producer. Hence, it was concluded that female Napier grass has a good potential of becoming a biomass producer in bioethanol production in Malaysia

Effects of plant growth regulators, carbon sources and pH values on callus induction in Aquilaria malaccensis leaf explants and characteristics of the resultant calli

The endangered tropical tree, Aquilaria malaccensis, produces agarwood for use in fragrance and medicines. Efforts are currently underway to produce valuable agarwood compoundsn tissue culture. The purpose of this study was to develop an optimal growth medium, specifically, the best hormone combination for callus suspension culture. Using nursery-grown A. malaccensis, sterilized leaf explants were first incubated on basic Murashige and Skoog (MS) gel medium containing 15g/L sucrose and at pH 5.7. Different auxin types including 1-naphthaleneacetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D), and indole-3-butyric acid (IBA), were tested at various concentrations (0.55, 1.1 and 1.65 μM) using the basic medium. Leaf explants were incubated for 30 days in the dark. Callus induced by 1.1 μM NAA had the highest biomass dry weight (DW) of 17.3 mg; however the callus was of a compact type. This auxin concentration was then combined with either 6-benzylaminopurine (BAP) or kinetin at 0.55, 1.1, 2.2 or 3.3 μM to induce growth of friable callus. The 1.1μM NAA + 2.2μM BAP combination produced friable callus with the highest biomass (93.3mg DW). When testing the different carbon sources and pHs, sucrose at 15g/L and pH at 5.7 yielded highest biomasses at 87.7mg and 83mg DW, respectively. Microscopic observations revealed the arrangement of the friable cells as loosely packed with relatively large cells, while for the compact callus, the cells were small and densely packed. We concluded that MS medium containing 15 g/L sucrose, 1.1 μM NAA + 2.2 μM BAP hormone combination, and a pH of 5.7 was highly effective for inducing friable callus from leaf explants of A. malaccensis for the purpose of establishing cell suspension culture

Oil-heat treatment of rubberwood for optimum changes in chemical constituents and decay resistance

Effects of oil—heat treatment on chemical constituents and decay resistance of rubberwood (Hevea brasiliensis) were investigated in this work. Oil—heat treatment palm oil as heating medium was carried out by immersing rubberwood samples (300 mm longitudinally × 20 mm radially × 20 mm tangentially) in hot oil bath. Wood samples were immersed in the palm oil at temperatures and time periods ranging from 172 to 228 °C and 95 to 265 min respectively. Cellulose, hemicellulose and lignin contents and weight loss of samples by the fungus Pycnoporus sanguineus were evaluated. Four linear and one quadratic models were developed using response surface methodology. High adjusted r² values were obtained and the adequacy of the models was confirmed. Cellulose and hemicellulose reduced in treated samples. Such reductions became greater with increasing temperature and exposure time. However, lignin content of samples increased with increasing temperature of treatment and extended time. Decay resistance of treated samples against P. sanguineus improved with increased treatment temperature and time. The enhancement in decay resistance was highly related to chemical constituents in the treated sample

Biomodification of Kenaf using white rot fungi.

White rot fungi can be used as a pretreatment of biomass to degrade lignin. It also alters the structure of the lignocellulosic matter, thus increasing its accessibility to enzymes able to convert polysaccharides into simple sugars. This study compares the ability of two species of white rot fungi, Pycnoporous sanguineus and Oxyporus latemarginatus FRIM 31, to degrade lignin in kenaf chips. The white rot fungi were originally isolated from the tropical forest in Malaysia. Kenaf chips were first inoculated with each fungus separately using corn steep liquor as a fungal growth promoter. The kenaf chips were inoculated with white rot fungus for a period of 1, 2, 4, 8 and 16 weeks, after which they were observed under the scanning electron microscope (SEM). Chemical analyses were conducted following TAPPI Standard Methods and Fourier Transmission Infra Red (FTIR). SEM observations showed evidence of fungal colonization. When calculating weight loss, both P. sanguineus and O. latemarginatus FRIM 31 showed the greatest reduction. Amounts by mass of cellulose, hemicelluloses, extractives, and lignin in the treated kenaf chips all were lowered. The results show that O. latemarginatus FRIM 31 had a greater ability to degrade lignin when compared to P. sanguineus

Response surface methodology models of processing parameters for high performance phenolic compreg wood

The aim of the study was to develop response surface methodology (RSM) models for polymer loading, density, dimensional stability, strength and stiffness of compressed wood of sesenduk (Endospermum diadenum) treated with phenol formaldehyde (PF). Central composite design (CCD) using RSM with three processing parameters was studied in their specific ranges: PF concentration (PC) from 24-40%, pre-curing time (PCT), 3-9 h and compression ratio (CR), 70-90%. The experimental design was analysed and interpreted using the Design Expert Software (Stat Ease version 8) and the responses of 3d plots were built using the same software. Quadratic models in terms of PC, PCT and CR were developed for polymer loading, density, reduction in water absorption and modulus of rupture in static bending. Multiple linear equations were developed for anti-swelling efficiency and modulus of elasticity. The experimental values were in good agreement with predicted ones and the models were highly significant with correlation coefficients between 0.626 and 0.926. PC and CR had significant effects on the responses. The range of PCT used did not significantly affect the responses. It was also found that the improvement of properties ranged from moderately to highly correlated with the polymer loading in the compreg wood

Alkaline sulfite anthraquinone and methanol pulping of bamboo (Gigantochloa scortechinii)

Alkali ratios and cooking time of the alkaline sulfite anthraquinone(AQ)and methanol (ASAM) pulping process of bamboo (Gigantochloa scortechinii)were studied. Bamboo chips were cooked at three different levels of sodium hydroxide and cooking time, namely14, 16, or18% for 60, 90, or 120 minutes. Pulping parameters that remained constant were the use of 0.5% ethylene diamine tetraacetic acid (EDTA), with an 80/20 ratioNa2SO3/NaOH, 0.1% anthraquinone, 15% methanol, and a temperature of 170 °C in the cooking process. Samples prepared using 14% NaOH and 90 min of cooking time resulted in the highest pulp yield, 52.4%, and a Kappa number of 18.1. It seems that 16% sodium hydroxide and 90 min of cooking time are the most appropriate cooking conditions, giving a 49.1% pulp yield and 14.2Kappa number. The quality of bamboo pulp produced by the ASAM pulping process was found to be beneficial for the use in paper and board manufacturing

Biological of Malaysian canes modified with polymer.

The biological resistance against white and brown rot fungi of Calamus manan (manau) and C. ornatus (mantang) canes modified with polymer was investigated

Characteristics of pulp produced from refiner mechanical pulping of tropical bamboo (Gigantochloa scortechinii)

Bamboo properties are somewhat similar to certain timbers but it has an advantage of having longer fibres, making it suitable for the production of pulp for paper and hardboard. However, the pulping process is a very crucial stage to produce fibres with an optimum quality. This study was carried out to characterize the pulp of Giganrochloa scortechinii using refiner mechanical pulping (RMP). The parameters evaluated included the effects of pre-treatment soaking in NaOH or steaming of chips and effects of refiner plate gap on pulp quality. Pulp quality was assessed based on the properties, yield, and lignin content of fibres. The pre-treatment with NaOH at 60°C for 6 h was found to produce superior quality pulp and lesser lignin content compared to pre-treatment by steaming at 150°C for 3 h. Meanwhile, the refiner plate gap test showed that the two cycles of refining (2.5-mm followed by 0.5-mm plate gap) reduced the lumpiness of the fibre, but it had lower felting power and Runkel ratio. Two cycles of refining process also led to higher fibre yield, produced more unbroken and slender fibres as compared to when one cycle treatment using 2.5-mm plate gap was used

Investigation on the effect of beating on the physical and mechanical properties of untreated kenaf based insulation paper

This paper presents a study on the effect of beating on the physical and mechanical properties of untreated kenaf based insulation paper for application in transformers. The paper was developed based on kenaf bast fibers through soda pulping process. The pulps were subjected to beating process up to 9000 revolutions where the thickness, density and tensile index of paper were measured. It is found that the tensile index and the density of the paper increases while the thickness of the paper decreases with beating revolutions