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Hydrogels are an attractive platform for drug delivery to the skin. Current cellulose hydrogel developments commonly focus on readily available bleached woody cellulose. Considering the detrimental environmental impacts of bleaching reagents, unbleached non-woody biomass was proposed as an alternative. Herein, this study aims to develop hydrogel from native cellulose extracted from oil palm empty fruit bunches for dermal drug delivery with an emphasis on evaluating the effect of alkali solvent compositions on hydrogel formation. Unbleached dissolving pulps were solubilized in alkali solvents containing sodium hydroxide (NaOH) (6-8%w/v) and urea (4-6%w/v) before crosslinking. Hydrogels were loaded with ibuprofen for skin permeation studies. Light brownish hydrogels formed are aesthetically acceptable and biodegradable with low cytotoxicity. NaOH content has a dominant role over urea where thinner and deformable crosslinked network walls in a porous hydrogel structure are associated with high NaOH content. Synergistic effects (cellulose solubility: 94 %; swelling ratio: ~2800 %) were observed at 7%w/v NaOH and 4%w/v urea with low toxicity. Most hydrogels showed80 % of ibuprofen permeated into the skin and this increased with the swelling ratio of hydrogels. Unbleached cellulose pulps have excellent potential for hydrogel fabrication with outstanding physicomechanical properties for dermal drug delivery.

The kapok (Ceibapentandra (L.) Gaertn) seed fibre is unicellular with length up to 35 mm, however, it is covered by a hydrophobic waxy layer that limits its application in paper production. In this study, the effect of various pulping methods namely mechanical, chemi-mechanical, semichemical and chemical pulping on kapok fibre properties was investigated. Each kapok pulp was then blended with the secondary fibre recovered from kraftliner board for handsheet making to examine their reinforcing ability on strength properties. The results showed that kapok mechanical pulps (with and without dewaxing (5% (v/v) diluted detergent) and chemimechanical pulp were unable to improve the strength properties of the handsheet. Kapok pulps chemically treated with 18–25% of sodium hydroxide gave a better effect on handsheet strength properties whilst fibre treated with 20% sodium hydroxide showing the highest increment. Although the reinforcing effect of the 4% native cooked starch was slightly higher than that of the 10% kapok pulp blended in recycled paper, the recycling potential of the latter was better as all strength properties retained unchanged after recycling. The findings indicated that kapok chemical pulp is a promising reinforcing fibre source with superior recycling potential.

Studies of bio-nanocomposites using sustainable green materials from biomass waste are presently gain the attention worldwide. This study investigated the properties of bio-nanocomposite films from polyvinyl alcohol incorporated with 1%, 3%, and 5% via solvent casting method using various types of oil palm trunk cellulose nanocrystals isolated using various types of treatment. The produced bio-nanocomposite films were characterized for their mechanical behavior, morphological properties, thermal properties, and functionality groups and the effect of adding the oil palm trunk cellulose nanocrystals into the bio-nanocomposites films were then evaluated. The results showed that the mechanical properties and thermal stabilities of the bio-nanocomposite films increased with the incorporation of cellulose nanocrystals. The bio-nanocomposite films added with 3% cellulose nanocrystals with pre-hydrolysis treatment showed better mechanical and thermal properties and hence have a great potential to be utilized as a raw material or reinforcement in the packaging industries.

The use of nanocrystalline cellulose (NCC) as a renewable and green biomaterial in diverse value-added applications has roused substantial interest. Sourcing NCCs from the abundantly available non-woody biomass becomes attractive due to its high cellulose content and low cost. Acid hydrolysis using mineral acids has been widely explored as a facile, low-cost, and efficient way of isolating NCCs. Still, the technical aspect of the extraction procedure is lacking. This review gathers the available knowledge on the NCC extraction using hydrolysis with mineral acids from non-woody biomass and provides a critical overview of the extraction parameters to be considered from the feedstocks and related pretreatment to the final hydrolysis procedure. To fulfill an operationally feasible production of NCCs, this review shares considerations and challenges on the biomass characteristics and pretreatment as well as hydrolysis parameters for optimizing NCC production and tailoring its application.

Ponding system or land application techniques are widely used at industrial scale to treat palm oil mill effluent (POME) prior to discharge to the environment. POME is considered as one of the major problems that has generated voluminously from the palm oil industries. The main purpose of this article is to organize the scattered available information on various aspects and a wide range of promising current POME treatments including biological microorganisms, physicochemical methods of coagulation, and membrane and thermochemical process. In addition, the integrated system of anaerobic-aerobic bioreactor (IAAB), which has been touted as highly efficient with easy control at acceptable temperature range and shorter treatment time, has potential to be exploited for POME treatment. The main influencing factors for IAAB POME treatment are highlighted as outstanding characteristics for challenges and future prospects.

In this study, a new approach viz. total glucose yield (TGY) was used as the single response for the optimization of various pretreatments of oil palm ( Elaeis guineensis ) empty fruit bunch (EFB) fibre through response surface methodology. TGY was calculated by multiplying the enzymatic saccharification yield and pretreatment solid recovery yield. The optimum condition of each pretreatment was calculated based on the estimation model built and then verified experimentally. The optimum conditions for water, acid and alkali pretreatments were 170 °C for 30 min, 120 °C for 45 min in 2.0% (v/v) H 2 SO 4 solution and 110 °C for 45 min in 3.0% (v/v) NaOH solution, respectively. Based on chemical composition analysis, although both the water and alkali pretreated EFB fibres exhibited more than 99% of the cellulose was converted into glucose, water pretreated fibre achieved the highest TGY, as it retained higher recovered glucose content. This study also verified that the use of TGY on the basis of original fibre weight was more appropriate than the enzymatic saccharification yield in the optimization study of biomass pretreatment, as it also considered the loss of the cellulose during pretreatments.

Hydrogels are an attractive system for a myriad of applications. While most hydrogels are usually formed from synthetic materials, lignocellulosic biomass appears as a sustainable alternative for hydrogel development. The valorization of biomass, especially the non-woody biomass to meet the growing demand of the substitution of synthetics and to leverage its benefits for cellulose hydrogel fabrication is attractive. This review aims to present an overview of advances in hydrogel development from non-woody biomass, especially using native cellulose. The review will cover the overall process from cellulose depolymerization, dissolution to crosslinking reaction and the related mechanisms where known. Hydrogel design is heavily affected by the cellulose solubility, crosslinking method and the related processing conditions apart from biomass type and cellulose purity. Hence, the important parameters for rational designs of hydrogels with desired properties, particularly porosity, transparency and swelling characteristics will be discussed. Current challenges and future perspectives will also be highlighted.

Response surface (RSM) optimization of selected cultural parameters and the effect of various nitrogen sources on xylanase production by novel strain of Aspergillus niger via solid state fermentation of oil-palm-empty-bunches (OPEFB) were assessed. The newly isolated oil-palm-field-domiciled strain of Aspergillus niger was identified based on rRNA analysis as Aspergillus niger USM SD2 (GenBank accession no. 2 ) value of 0.95. Xylanase activity was optimum at 25 °C, initial moisture-substrate ratio 4:1; pH 6.3 and total inoculums size, 2 × 10 6 spores/ml. At optimum production period, xylanase production was enhanced by more than 100% of its value prior optimization. Moreover, the use of yeast extract (Y/E) enhanced xylanase production better than any other nitrogen sources evaluated. Consequently, at its optimum concentration (15 g/l), the addition of Y/E enhanced xylanase production such that final activity (3246 IU/gds) was 160% and 29% higher than activities (1250 IU/gds) prior to and after (2512 IU/gds) parametric optimization respectively. Further analyses also showed that xylanase production by A. niger USM SD2 was independent of period of incubation and, hence, its growth rate.

Poor or non-utilisation of the xylose fractions of lignocellulosic biomass is a serious impediment to the achievement of energy security through lignocellulosic ethanol. In this work, the potential of sustainable ethanol production from oil palm empty fruit bunches (OPEFB) by co-fermentation of its glucose and xylose components was assessed. Simultaneous co-saccharification and co-fermentation (SScF) was compared with three other fermentation techniques to evaluate bioconversion of mild-alkaline-treated OPEFB for efficient bioethanol production. Hydrolysis was done by the synergistic actions of commercial cellulase (50 FPU/gds) supplemented with on-site crude hemicellulase at unit ratio of 1 FPU: 5 U. After pre-treatment, 79.0% and 79.3% respectively of total glucan and xylan were recovered while 91.9% and 90.6% of the respective polymers were hydrolyzed to fermentable sugars. At 3.4% (w/v) substrate loading, 89.5% theoretical ethanol yield, equivalent of 0.33 g/g raw OPEFB (418.9 L/tonne) was achieved by using SScF. This was higher than 84.9% (0.31 g/g = 397.6 L/tonne raw OPEFB) achieved by separate co-hydrolysis and co-fermentation (SHcF) which is the closest among other fermentation techniques compared. By our knowledge, the yield achieved by the co-fermentation techniques used in this study has not been reported in any previous research which produced ethanol from OPEFB.

Crude hemicellulase by novel mycoparasitic Trichoderma asperellum (GenBank accession nos. T. asperellum could withstand up to 50% selected hydrolytic and fermentation inhibitors. Supplement of hemicellulase crude to Celluclast 1.5 L at 1FPU:5U enhanced the hydrolysis of alkaline-treated OPEFB biomass achieving a 91.7% saccharification yield, higher than 77.9% yield or 12.2% yield when no hemicellulase was used or used without addition of cellulase respectively. The high saccharification yield, which has not been attained in any previous report on OPEFB, demonstrates the potential of T. asperellum for the development of efficient enzyme system for lignocellulosic bio-conversion. As far as we know, this is the first report on enhancement of lignocellulosic co-hydrolysis through synergism of hemicellulase crude by T. asperellum and commercial cellulase.

Seaweed and cellulose are promising natural polymers. This article reviews the basic information and recent developments of both seaweed and cellulose biopolymer materials as well as analyses the feasible formation of seaweed/cellulose composite films. Seaweed and cellulose both exhibit interesting film-forming properties. Nevertheless, seaweed has poor water vapour barrier and mechanical properties, whereas cellulose is neither meltable nor soluble in water or common organic solvents due to its highly crystalline structure. Therefore, modification of these hydrocolloids has been done to exploit their useful properties. Blending of biopolymers is a must recommended approach to improve the desired characteristics. From the review, seaweed is well compatible with cellulose, which possesses excellent mechanical strength and water resistance properties. Moreover, seaweed/cellulose composite films can prolong a product’s shelf life while maintaining its biodegradability. Additionally, the films show potential in contributing to the bioeconomy. In order to widen seaweed and cellulose in biocomposite application across various industries, some of the viewpoints are highlighted to be focused for future developments and applications.

In this work, the effects of various pretreatments’ parameters on kenaf core fibre were analyzed statistically and optimized using Response Surface Methodology based on the total glucose yield. The chemical compositions of the pretreated fibres were examined to discuss the effect of pretreatment on the fibre hydrolysability comprehensively. The results showed that estimation model for each pretreatment of kenaf core fibre were polynomial equations. The optimum conditions for water, acid and alkali pretreatments were 170 °C for 45 min, 120 °C for 90 min in 2.0% H2SO4 solution and 140 °C for 60 min in 3.0% NaOH solution, respectively. Among the three pretreatments, water pretreatment achieved the highest total glucose yield (25.5%), followed by acid (20.0%) and alkali (18.2%) pretreatments. Based on chemical compositions analysis, both water and acid pretreatments were capable of eliminating almost 100% of hemicellulose with negligible removal of lignin while the alkali pretreatment removed both the lignin and hemicellulose more than 60%. This result revealed that the removal of hemicellulose showed greater influential in enhancing the enzymatic accessibility and hence, hydrolysability of kenaf core fibre.

In realizing the vast potential of lignocellulosic biomass residues generated by oil palm industry under the regime of ‘one-size-fits-all’ biorefinery concept, supercritical carbon dioxide (SC-CO2) technology offers great promise. Herein, we demonstrated a new eco-friendly pretreatment of oil palm trunk biomass based on SC-CO2 under controlled conditions of pressure (25, 35 and 45 MPa), temperature (80, 100 and 120 °C) and moisture content (0, 20, 40 and 60 %), and investigated their effect on enzymatic hydrolysis yields of the pretreated fractions. During pretreatment, biomass sample reacted with hot water in SC-CO2 which led to high diffusivities, promoting its disruption and xylan solubilisation as supported by various characterization techniques. This study illustrates that hydrolysis yields are influenced by process parameters, particularly the moisture content played a crucial role in the biomass disruption. The SC-CO2 pretreatment resulted in enhanced digestibility for all the pretreated fractions compared to the untreated biomass.

Non-wood lignocellulosic biomass is abundantly available, low cost, easy to process and consists of a short growth and harvest period; therefore, it is introduced as a potential feedstock biomass for bioethanol production. Common non-wood lignocellulosic biomasses are categorised into agricultural residues, native and non-wood plant fibres. The potential of non-wood lignocellulosic biomass as a resource for cellulosic ethanol production are determined and, analyzed in the context of their chemical composition, fibre production yield, total cellulose availability as well as the enzymatic saccharification efficiency after pretreatment. Based on the obtained data, agricultural residues show significant advantages in all contexts over other non-wood lignocellulosic biomasses. Moreover, pretreatment plays an important role in enhancing the enzymatic accessibility and hydrolysability of non-wood biomass. This review found that various pretreatments could be applied to enhance the enzymatic hydrolysability of different biomasses; however the major factors that vary the effectiveness of particular pretreatment on improving of different biomass hydrolysability have not been clearly highlighted. In addition, even though enzymatic saccharification of pretreated biomass is mainly highlighted in most of the cellulosic ethanol studies to evaluate the improvement of biomass hydrolysability, this data is unable to show the total glucose that obtained from the untreated biomass directly. In this study, the importance of total glucose yield is emphasized and it is calculated from various research data by multiplying the solid recovery yield by the enzymatic saccharification yield of the pretreated biomass, as it presents the percentage of the total glucose that could be converted directly from the original biomass. This work verifies that besides enzymatic saccharification yield, the solid recovery yield is also one of the major factors to be identified in cellulosic ethanol study.

In this study cellulose nanocrystals were isolated from oil palm trunk (Elaeis guineensis) using acid hydrolysis method. The morphology and size of the nanocrystals were characterized using scanning electron microscopy and transmission electron microscopy. The results showed that the nanocrystals isolated from raw oil palm trunk (OPT) fibers and hot water treated OPT fibers had an average diameter of 7.67 nm and 7.97 nm and length of 397.03 nm and 361.70 nm, respectively. Fourier Transform Infrared spectroscopy indicated that lignin and hemicellulose contents decreased. It seems that lignin was completely removed from the samples during chemical treatment. Thermogravimetric analysis demonstrated that cellulose nanocrystals after acid hydrolysis had higher thermal stability compared to the raw and hot water treated OPT fibers. The X-ray diffraction analysis increased crystallinity of the samples due to chemical treatment. The crystalline nature of the isolated nanocrystals from raw and hot water treated OPT ranged from 68 to 70%.

Kapok fibre is a promising raw material to produce sugar by enzymatic hydrolysis. In this work, effects of water, acid and alkaline pretreatments on the enzymatic sugar yield were studied through response surface methodology (RSM) and supported by the analysis of chemical compositions and physical structure of the fibre. For water pretreatment, reaction temperature and time were the independent variables while chemical concentration was also used as the third independent variable for acid and alkaline pretreatments. For all pretreatments, the enzymatic hydrolysis conditions were kept constant. The structure of pretreated fibre was also examined using scanning electron microscope (SEM). Results showed that water and acid pretreatments effectively dissolved hemicellulose of the fibre with the latter unveiled better results. The alkaline pretreatment resulted in the highest total glucose yield (g/kg of untreated fibre) as compared to water and acid pretreatments. SEM analysis illustrated that water and acid pretreatments led severe destruction of fibre structure; however, both of these pretreatments exhibited lower enhancement of enzymatic hydrolysability of kapok fibre as compared to that observed in alkaline pretreatment.

Residual lignin present in alkali pulps prepared from oil palm (Elaeis guineensis) empty fruit bunch was isolated using an enzymatic method and characterized successfully by pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). These pulps were prepared by soda-anthraquinone (AQ) and prehydrolysis (PH) soda-AQ cooking methods (pulp yields were 45.3 and 33.9%, respectively). Py-GC/MS of the residual lignin showed that two pyrolysis products which were indole and methylindole originating from the enzyme (contents 12 to 44%), in addition to eight pyrolysis products originating from syringyl (S) and guaiacyl (G) structure of lignin. Furthermore, palmitic acid was also detected in the residual lignin (contents 0.11 to 0.28%). The residual lignin was subjected to further purification by a cellobiose treatment method, and the quantity of enzyme present in the residual lignin was found to decrease after the treatment. Residual lignin in PH-soda-AQ pulp exhibited a higher S/G ratio (0.86 to 0.98) than that in soda-AQ pulp (0.76 to 0.97). This study showed that the contents of lignin (19 to 44%) and enzyme in enzymatically isolated lignin can be estimated by the Py-GC/MS method.

Cellulose nanocrystals were isolated from oil palm trunk by total chlorine free method. The samples were either water pre-hydrolyzed or non-water pre-hydrolyzed, subjected to soda pulping, acidified and ozone bleached. Cellulose and cellulose nanocrystal (CNC) physical, chemical, thermal properties, and crystallinity index were investigated by composition analysis, scanning electron microscopy, transmission electron microscopy, fourier transform infrared, thermogravimetric analysis and X-ray diffraction. Water pre-hydrolysis reduced lignin (

The feasibility of the production of cellulose acetate (CA) from recycled paper dust from carton boxes was examined. Two pre-treatments were carried out on the carton box’s paper dust (CPD) to improve the pulp properties for better effect of synthesis. The results showed that the acid and oxygen-alkaline pretreatments were capable of increasing the alpha-cellulose content from 80.5 percent to 87.3 percent and 85.3 percent, respectively. Both pre-treatments also decreased the hemicellulose and ash contents by more than 50 percent. The degree of substitution (DS) of the resultant CA from pre-treated paper dust was improved from 1.94 to 2.13-2.16. The CA that was synthesized from the recycled paper dust showed comparable DS and had a similar trend of Fourier Transform Infrared (FTIR) spectra. Both pretreated pulps also showed an increment in the degree of crystallinity and had maximum degradation effect of temperature when compared to CPD CA. However, all the cellulose acetates produced showed a lower DS and thermal stability compared to commercial cellulose acetate (C CA). The degree of crystallinity of all the cellulose acetate was decreased in comparison to the original material.

The energy crisis has become a crucial issue. The rapid depletion of the fossil fuels has driven the world to utilize renewable energy (RE) sources. To develop RE industries, the Malaysian government has been continuously reviewing its energy policy and undertaking intensive efforts to ensure long-term reliability in the energy supply. The most attractive and practical choice to replace fossil fuels as the main energy source is biofuels, which are mostly in liquid form. In Malaysia, the transportation sector has become the main driver for increasing the liquid fuel demand. This study outlines the importance of second-generation bioethanol as a potential energy source for the Malaysia transportation sector and its future development perspectives. In this work, it is shown that Malaysia has consistently promoted the RE industry in its energy policy, over non-renewable conventional energy resources with their negative impact to the environment. In Malaysia, which has a significant amount of agricultural activities, agricultural wastes have become a very promising alternative source for second-generation bioethanol (SGB) production. It is estimated that the biomass availability and its potential energy generated are 50,919 dry kton/year and 13,343 kton/year, respectively. The estimated energy generated from biomass can contribute approximately 21.5% of the national energy requirement. In addition, the key drivers for Malaysia to move towards sustainable energy sources, such as SGB, are discussed. SGB can contribute to energy security and help to reduce CO 2 emissions in Malaysia. SGB is also economically feasible. Furthermore, the Malaysian market for bioethanol is potentially much larger than the market for biodiesel, because a much larger portion of the vehicle fleet runs on gasoline. Hence, implementing and promoting second-generation bioethanol effectively is definitely a strategic move for Malaysia to become a self-sufficient country in the future.

Tri-n -butyl phosphate (TBP) was used as carrier for the transport of chromium (VI) through a hexane bulk liquid membrane. The transport efficiency of chromium (VI) by TBP was investigated under various experimental conditions such as pH of the feed phase (Cr (VI) solution), concentration of the receiving phase (NaOH solution), concentration of TBP in membrane, rate of stirring, effect of transport time, type of solvent, Cr (VI) concentration in feed phase, and effect of temperature. The transport efficiency increased with increasing carrier concentration from 7.5 × 10 − 2 to 2.25 × 10 − 1 mol/L. At high pH (donor phase) the transport rate of chromate ions decreased. At high stirring speed (300 rpm) the Cr (VI) transport from the feed phase to the strip phase was completed within 5 h at 27 °C. Under optimum conditions: donor phase 4.8 × 10 − 4 mol/L K 2 Cr 2 O 7 solution at pH 1.0 ± 0.1, acceptor phase 1.0 mol/L NaOH solution, membrane phase 2.25 × 10 − 1 mol/L, stirring speed 300 rpm, and temperature 27 °C, the flux rate was found to be 2.90 × 10 − 7 mol/m 2 s.

Liquid–liquid extraction (LLE) of methylene blue (MB) from industrial wastewater using benzoic acid (extractant) in xylene has been studied at 27 °C. The extraction of the dye increased with increasing extractant concentration. The extraction abilities have been studied on benzoic acid concentration in the range of 0.36–5.8 × 10−2 M. The distribution ratio of the dye is reasonably high (D = 49.5) even in the presence of inorganic salts. Irrespective of the concentration of dye, extraction under optimal conditions was 90–99% after 15 min of phase separation. The extracted dye in the organic phase can be back extracted into sulphuric acid solution. The resultant recovered organic phase can be reused in succeeding extraction of dye with the yield ranging from 99 to 87% after 15 times reused, depending on the concentration of the initial feed solution. Experimental parameters examined were benzoic acid concentration, effect of diluent, effect of pH, effect of initial dye concentration, effect of equilibration time, various stripping agents, aqueous to organic phase ratio in extraction, organic to aqueous phase ratio in stripping and reusability of solvent.

In this study cellulose nanocrystals were isolated through acid hydrolysis process from parenchyma and vascular bundle of oil palm trunk (Elaeis guineensis). The morphological properties of obtained cellulose nanocrystals were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The microscopy images showed smoother and cleaner surface of parenchyma cellulose nanocrystals when compared to vascular bundle cellulose nanocrystals. The TEM image shows a higher length and diameter for parenchyma cellulose nanocrystals compared to vascular bundle cellulose nanocrystals. The Fourier transform infrared (FTIR) spectra showed changes in functional groups after acid hydrolysis due to removal of lignin, hemicelluloses and other impurities in both type of cellulose nanocrystals. Crystallinity index of cellulose nanocrystals was observed higher for vascular bundle as compared to parenchyma. Thermogravimetric analysis (TGA) was performed to study the thermal stability of cellulose nanocrystals and it was observed higher for parenchyma cellulose nanocrystals compared to vascular bundle.

Summary A water prehydrolysis-soda pulping sequence for the preparation of dissolving pulps from oil palm fibre (empty fruit bunches) was investigated using a response surface methodology (RSM) statistical experiment design. Five response variables of screened yield, Kappa number, α-cellulose, viscosity and ash content were statistically analyzed with respect to the three input variables of pulping temperature (T), time-at-temperature (t) and alkali level (A), while keeping the prehydrolysis conditions constant. Optimum conditions were: T = 161°C, t = 100 min and A= 26.1%. Values predicted by RSM for screened yield, Kappa number, α-cellulose, viscosity and ash content at the optimum are 31.2%, 6.0, 96.9%, 16.1 cps and 0.15%, respectively. These values were experimentally verified and very close agreement between experimental and predicted values was obtained.

Bamboo fiber was treated using a high-pressure enzyme hydrolysis process. The process performance was compared with the pulping and bleaching process for bamboo fiber. Several analytical methods, including field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry, and differential scanning calorimetry, were employed to determine the physicochemical and thermal properties of the treated cellulosic bamboo fiber. It was found that the pressurized enzyme hydrolysis treated bamboo fiber had the most uniform morphological structure, along with lowest crystallinity and highest thermal stability. Thus, utilizing high-pressure enzyme hydrolysis is the most effective process for treating fiber to remove non-cellulosic components from the raw material, including lignin, hemicelluloses, and waxy materials.

Various pretreatments on Ceiba pentandra (L.) Gaertn. (kapok) fiber prior to enzymatic hydrolysis for sugar production were optimized in this study. The optimum conditions for water, acid, and alkaline pretreatments were 170°C for 45 min, 120°C for 45 min in 1.0% (v/v) H2SO4 solution and 120°C for 60 min in 2.0% (v/v) NaOH solution, respectively. Among the three pretreatments, the alkaline pretreatment achieved the highest total glucose yield (glucose yield calculated based on the untreated fiber) (38.5%), followed by the water (35.0%) and acid (32.8%) pretreatments. As a result, the relative effectiveness of the pretreatment methods for kapok fiber was verified as alkali>water>acid at the condition stated.

The importance of bioethanol currently has increased tremendously as it can reduce the total dependency on fossil-fuels, especially gasoline, in the transportation sector. In this study, Ceiba pentandra (kapok fiber) was introduced as a new resource for bioethanol production. The results of chemical composition analysis showed that the cellulose (alpha- and beta-) contents were 50.7%. The glucose composition of the fiber was 59.8%. The high glucose content indicated that kapok fiber is a potential substrate for bioethanol production. However, without a pretreatment, the kapok fiber only yielded 0.8% of reducing sugar by enzymatic hydrolysis. Thus, it is necessary to pre-treat the kapok fiber prior to hydrolysis. Taking into account environmentally friendliness, only simple pretreatments with minimum chemical or energy consumption was considered. It was interesting to see that by adopting merely water, acid and alkaline pretreatments, the yield of reducing sugar was increased to 39.1%, 85.2% and >100%, respectively.

Paper dust is a kind of cellulosic waste that is generated by converting operations in paper mills. It was derived to a low-grade cellulose acetate in this study. Papers made from recycled fiber were then impregnated with the resultant cellulose acetate. Effects of impregnation conditions on the paper properties were statistically investigated by employing central composite design (CCD) based response surface methodology (RSM). Four response variables, namely density, burst index, smoothness, and rate of surface wettability were analyzed. Polynomial estimation model of each response was developed as functions of three independent variables, which are pressing temperature (T), dipping time (D), and concentration of cellulose acetate (C). The paper which was impregnated based on the calculated optimum condition (T: 163 oC, D: 2.8 minutes, and C: 2.7 percent), possessed a density of 0.5450 g/cm3, rate of surface wettability of 0.012o/s, burst index of 2.84 kPa m2/g, and paper smoothness of 475 mL/min. There was no significant difference between the experimental values and the predicted values calculated from estimation models. The cellulose acetate impregnated Braille papers made from recycled fibre was found to have better properties than those of commercial Braille paper in terms of rate of surface wettability and burst index.

Kenaf core fibre was introduced for cellulosic alcohol production. Various pre-treatments with and without oxygen-alkali extraction were employed in this study. The effects of pre-treatments on the enzymatic hydrolysability of kenaf core fibre for sugar production were investigated by FTIR and SEM to characterise the chemical structure and examine the morphology of the fibre, respectively. Both characterisation results were supported by chemical composition analysis of biomass. Results showed that the glucose yield of the fibre with a pre-treatment followed by an oxygen-alkali extraction was remarkably higher than that of the counterpart without an oxygen-alkali extraction. Chemical and morphology analyses indicated that the combination of oxygen-alkali extraction with water and acid pre-treatments could increase the fibres saccharification due to large removal of hemicellulose as well as lignin, and severe structural modifications of fibre. Nevertheless, the combination of alkali pre-treatment with oxygen-alkali extraction did not change the chemical composition and surface morphology of the fibre dramatically. [Received: January 3, 2016; Accepted: April 24, 2016]

This study was carried out to identify an appropriate alkaline pulping condition for Malaysia cultivated kenaf (Hibiscus cannabinus L.). The chemical composition of the kenaf bast and core fibers, and also whole stalk with different growing time were examined prior to pulping attempts. The results of various soda-AQ pulping showed that the degree of carbohydrate degradation and delignification increased with the increase of active alkali and cooking temperature, but decreased with the increase of liquor to material (L:M) ratio. The most satisfactory properties of pulp and handsheets from bast could be attained by employing soda-AQ pulping with 19.4% active alkali, 0.10% AQ, and L:M ratio of 7:1 cooked for 2 hours at 160˚C. Besides, it was also found that a mild alkaline pre-impregnation prior pulping improved the pulp viscosity and handsheets’ strength properties, especially the tensile index and folding endurance effectively. Moreover, among the three alkaline pulping processes—kraft, kraft-AQ, and soda-AQ—the results of pulp and handsheet properties showed that the soda-AQ pulp was comparable or even slightly of higher quality than the kraft pulps. Between the unbeaten bast and core soda-AQ handsheets, the strength properties of the core were higher than the bast, as the thin-walled core fibers exhibited much better conformability than the thick-walled bast fibers.