Papers by Keyword: Lignocellulose

Abstract: The purpose of this study is to explore the use of laser additive manufacturing of bamboo powder to produce items with fewer variations than the traditional heat press method using a die. Although metal and resin powders are commonly used in powder additive manufacturing, bamboo powder presents unique challenges owing to its lack of material uniformity, low carbonization temperature, and dependence on pressure for adhesion. To address these issues, the appropriate laser power and irradiation time were determined by irradiating the laser at several power levels and examining its effects on the powder temperature and chemical changes during molding. The results indicated that rapid heating occurred at approximately 150 °C, and carbonization began at approximately 190 °C. As the energy loss for carbonization decreases with increasing laser power, this method is expected to be effective for producing bamboo products with fewer variations. In addition, restriction of continuous oxygen inflow by the glass plate lid makes it feasible to prevent heat generation and carbonization. Furthermore, pressurization by the glass plate makes it feasible to improve adhesion. Future research will focus on the suppression of carbonization by inert gas and heating at low temperatures for long periods of time, as well as the effects of different magnitudes of pressure on the process.

Abstract: To address global environmental challenges and mitigate bamboo-related ecological damage, this study focuses on the development of self-adhesive molded products utilizing solely bamboo fibers and powder obtained through machining center extraction. However, the mechanical properties of these molded products remain inadequate. This study utilizes Scanning Electron Microscope (SEM) and Fourier transform infrared spectrometer (FTIR) analyses to explore the disparities associated with chip size as raw materials for molded products. Bamboo fiber, characterized by its substantial cellulose content and high strength, is contrasted with bamboo powder, which contains significant amounts of lignin and exhibits potential adhesive properties. Building upon these findings, the powder was added to the conventional fiber alone, with results demonstrating that a predetermined ratio (20%) of the powder yields optimal mechanical properties. Moreover, employing a parameter representing the degree of lignin flow utilized in previous molding studies, the study establishes the optimum molding conditions (PD'=1.031) to maximize tensile strength (37.8 MPa) when incorporating a 20% powder mixture.

Abstract: Oil Palm Empty Fruit Bunch (OPEFB) is lignocellulosic biomass waste generated from palm oil processing industries. Due to its significant compositions of cellulose, hemicellulose, and lignin, OPEFB can be further utilized and converted into value-added chemical products which can be used as alternative energy. Hence, the focus of this research is to analyze the effect of microwave pre-treatment (MP) and pressure cooker pre-treatment (PCP) parameters on OPEFB lignin reduction. The treated OPEFB was directly processed using two serial fungal treatment processes. The first fungal treatment process (FT-1) was to maximize the OPEFB lignin removal while the second fungal treatment process (FT-2) was to maximize the glucose production. Combination of microbes such as Phanerochaete chrysosporium, Trichoderma harzianum, Aspergillus niger, and Tricodherma viride was used for both fungal treatment processes. The OPEFB passing 25-mesh screening was used as raw materials. The raw materials mixed with 0.05 w/w NaOH pellets and water to achieve a concentration ratio of 3/50 (w/v) were pre-treated with either MP or PCP. Subsequently, the slurry produced from the pre-treatment process was introduced to FT-1 (P. chrysosporium for 5 days) and finally to FT-2 (T. harzianum, A. niger and T. viride for 4 days). The compositions of lignin, cellulose, hemicellulose, and glucose were analyzed at each process transition and the end of the whole process. It was observed that PCP (60 mins) was the best pre-treatment process with 39.23%-w of lignin removed. On the other hand, combination of MP (150 watts, 60 mins) was followed with FT-1 removed 66.67%-w of lignin. Only around 38.37%-w of lignin was removed when using the whole process, e.g., MP (150 watts, 60 mins), FT-1, and FT-2. The highest composition of glucose, ca. 131.02%-w, was obtained when 40-min PCP followed with FT-1 and FT-2 was applied. The obtained results exhibited that large lignin removal did not necessarily promote high glucose yield in the final product as observed in the 60-min PCP, e.g., P. chrysosporium consumed not only lignin but also presumably hemicellulose and cellulose.

Abstract: Necessity for reduction of greenhouse gases emissions, the growing demand for improvement of biorefinery technologies and the development of new biorefining concepts, oblige us as a society, mainly scientists, to develop novel biorefinery approaches. The aim of this research was to comprehensively characterize lignocellulosic biomass that was obtained after 2-furaldehyde production, in terms of further valorization of this resource. This research shows that birch wood chips can be used in the new biorefinery processing chain for production of 2-furaldehyde, acetic acid and subsequent cellulose pulp obtaining, using thermomechanical and alkaline peroxide mechanical pulping process. In addition, obtained lignocellulosic residue was also characterized. Unique bench-scale reactor system was used to obtain a lignocellulosic material without pentoses and with maximum preservation of cellulose fiber for further use. Studies on the deacetylation and dehydration of birch wood hemicelluloses of pentose monosaccharides to 2-furaldehyde and acetic acid using orthophosphoric acid as a catalyst were carried out. Results showed that depending on the used pretreatment conditions the 2-furaldehyde yield was from 0.04 to 10.84 % o.d.m., the acetic acid yield was from 0.51 to 6.50 % o.d.m. and the lignocellulose residue yield was from 68.13 to 98.07 % o.d.m. with minimal content of admixtures. In addition, experimentally the optimal 2-furaldehyde production conditions regarding to purity and usability of cellulose in leftover of lignocellulosic material were developed. Best results in terms of both 2-furaldehyde yield and purity of residual lignocellulose were obtained in experiment where catalyst concentration was 70%, catalyst amount 4 wt.%, reaction temperature 175 °C and treatment time 60 min. By performing alkaline peroxide mechanical pulping of the relevant LC residue, it was possible to obtain pulp with tensile index comparable to standard printing paper, indicating that it is possible to perform stepwise 2-furaldehyde production with subsequent pulping to obtain various value added products.

Abstract: Process parameters for the alkali-impregnation of cogon and its combination with steam explosion were evaluated and optimized using Response Surface Modeling (RSM). Dried cogon (10% w/v) was impregnated in diluted base (1, 2, 3% (w/w) NaOH) at different ranges of temperature (50, 85,120 °C) and time (15, 32.5, 50 min), and then subjected to enzymatic saccharification using 60 FPU/g Accelerase 1500TM. The concentration of reducing sugar released was measured using Nelson-Somogyi Colorimetric Method. The RSM showed that the optimum condition, predicting 10% Reducing Sugar Yield (RSY), was treatment of 10 % (w/v) cogon with 1.5% NaOH (w/v) at 73 °C for 15 min. Upon validation, done in triplicates, 13+1.0% RSY was obtained. The optimally-impregnated cogon was subjected to a steam explosion treatment to improve its saccharifiability. The factors varied were temperature (170 to 225 °C) and exposure time (250 to 800 s). Upon saccharification of the steam-exploded samples, the RSM indicated that the best steam explosion condition, predicting 14% RSY, was 225 °C and 800 s. Upon validation, 15+0.5% RSY was obtained. Steam explosion improved the saccharifiability of NaOH-impregnated cogon by 15%.

Abstract: In this study the effect of mixed culture of Zymomonas mobilis and Pichia stipitis to produce bioethanol from Solid Waste Arenga pinnata (SWAP) was investigated. The fermentation liquid substrate was resulted from an integrated process of pretreatment and enzymatic hydrolysis. Combination of diluted acid and ethanol organosolv pretreatment was used to increase the SWAP lignin removal. Raw pretreatment was used to decrease the SWAP particle size to 200 mesh. Acid pretreatment was done using 5% (v/v) diluted sulfate acid. Acid pretreated SWAP was treated for 65 min with organosolv pretreatment. Enzymatic hydrolysis by a combination of cellulase and xylanase was done for 48 h to convert cellulose into reducing sugar. The surfactants (Tween 80) addition was done to increase the sugar yield of the hydrolysis process. Fermentation variable consist of single culture of Z. mobilis as the control and mixed culture of Z. mobilis and P. stipitis, the microorganisms used to convert glucose and xylose into ethanol. The number of inoculum used in this experiment was more than 1.4 billion cells and the duration of fermentation process was 72 h. The delignification process decreased 95.43% lignin in SWAP. X-ray Diffraction (XRD) analysis assay showed an increase of crystallinity index of SWAP with pretreatment combination to 37.87%. Enzymatic hydrolysis by a combination of cellulase and xylanase with the addition of Tween 80 produced 9.16 gr glucose/L reducing sugar concentration. The highest ethanol resulted by fermentation process using mixed culture of Z. mobilis and P. stipitis with 0.33% (v/v) ethanol concentration and 0.57 (g ethanol/g reducing sugar) ethanol yield. Fermentation process using single culture Z. mobilis resulted 0.28% (v/v) ethanol concentration, and 0.48 (g ethanol/g reducing sugar) ethanol yield. The mixed culture fermentation with Z. mobilis and P. stipitis resulted ethanol yield 19 % higher than the single culture fermentation using Z. mobilis.

Abstract: In this paper we present the results of a study of the physical and chemical properties of activated lignocellulose obtained in the process of steam explosion treatment of various breeds of wood. It is shown that fibrous material has a high potential for scientific and commercial use: in the field of production of pulp for paper and cardboard production in a more efficient way, to obtain microcrystalline cellulose by hydrolysis, to produce coarse lignocellulosic fibers for the production of construction and insulation boards with new properties. The scope of activated lignocellulose is not limited only to these directions, but can be significantly expanded due to the competent use of its physical and chemical properties.

Abstract: This research intends to explore the effect of pretreatment on lignoselulose to be used as raw material for bioethanol production. Pretreatment prepares lignocellulose compounds to be more easily hydrolyzed. Several variables were tested on oil palm empty fruit bunch (OPEFB) i.e. temperature, NaOH concentration, and particle size. According to the method of size reduction, there are two types of pretreatment which were milling and cutting. The first pretreatment type consisted of milling and screening resulting -+10-30, -30+40, -40+80, and-80 mesh. Each size fractions were then soaked in water at 90 °C for 2 hours. Meanwhile the second type consisted of cutting to 1 cm length followed by soaking in NaOH solutions for 2 hours. The operating temperatures at the second type were varied at 90 °C, 120 °C, 150 °C, 170 °C while the NaOH concentrations applied were 0%, 0.5%, 1%, 2%, 5%, 10%.The pretreated OPEFB was then hydrolyzed using cellulase produced by Aspergillus niger grown in situ. It was revealed that the relatively good pretreatment condition was milling to-80 mesh followed by soaking in hot water at 90 °C. It gave the highest produced sugar concentration at 15 g/L while other type resulted only 5.8 g/L.

Abstract: A preliminary study was performed on enzymatic hydrolysis process for treating empty fruit bunch (EFB) fibre. The bioconversion of cellulose hydrolysis was carried out with soluble cellulase from Trichoderma reesei as the biocatalyst. Crucial trends such as substrate and enzyme loading influencing the enzymatic reaction were also studied in order to enhance the cellulose conversion. The results indicate that as the enzyme loading was increased, the EFB conversion also increased until it reached 115.63 FPU/g of enzyme concentration, beyond this values, the reverse occurred. On the other hand, as the substrate loading was increased the conversion decreased. Inhibition of enzyme adsorption by hydrolysis products appear to be the main cause of the decreasing conversion at increasing enzyme loading and substrate loading.

Abstract: Alkaliphilic cellulases-producer fungi were isolated from soil of limestone areas in Perlis. The potential strain was isolated by soil dilution plate method on enriched selective medium using CMC as substrate at different pH levels. Eleven isolates of different morphological colonies were screened using the hydrolysis capacity test by Gram’s iodine. Out of eleven colonies, five showed positive results as the hydrolysis zone formed. BK1 showed the highest hydrolysis capacity among all sample strains for every pH levels. Eventually, four strains were selected to be further explored as cellulolytic fungi for the production of alkaline cellulase in the future.