Lignocellulosic Agricultural Wastes Research Articles

Agricultural Wastes and Their By-Products for the Energy Market

The conversion of lignocellulosic agricultural waste into biofuels and other economically valuable compounds can reduce dependence on fossil fuels, reduce harmful gas emissions, support the sustainability of natural resources, including water, and minimize the amount of waste in landfills, thus reducing environmental degradation. In this paper, the conversion of agricultural wastes into biomethane, biohydrogen, biodiesel, bioethanol, biobutanol, and bio-oil is reviewed, with special emphasis on primary and secondary agricultural residues as substrates. Some novel approaches are mentioned that offer opportunities to increase the efficiency of waste valorization, e.g., hybrid systems. In addition to physical, chemical, and biological pretreatment of waste, some combined methods to mitigate the negative effects of various recalcitrant compounds on waste processing (alkali-assisted thermal pretreatment, thermal hydrolysis pretreatment, and alkali pretreatment combined with bioaugmentation) are evaluated. In addition, the production of volatile fatty acids, polyhydroxyalkanoates, biochar, hydrochar, cellulosic nanomaterials, and selected platform chemicals from lignocellulosic waste is described. Finally, the potential uses of biofuels and other recovered products are discussed.

Efficient and low-cost mesoporous magnetic carbon composites derived from date palm stones for environmental remediation of hexavalent chromium

This study was performed to achieve two important scientifically challenging goals, environmental remediation of toxic heavy metals and utilization of agricultural lignocellulosic wastes. In this work, a series of mesoporous magnetic carbon (MMC) adsorbents were synthesized by carbothermic reduction at different temperatures employing date palm (Phoenix dactylifera L.) stones as the carbon source. The synthesized adsorbents were characterized by different technquies and the results confirmed the presence of zero-valent iron (ZVI) nanoparticles and other iron oxides as products of the carbothermal reduction. The nature of phases present, crystallite size and the surface properties were found to be dependent on the calcination temperature. The adsorbent MMC700 exhibited the smallest (ZVI) crystallite size 36 nm and the largest SBET 341 m2/g. All adsorbents showed mesoporous structure with mesopore average diameter lower than 6 nm. The performance was evaluated in the removal process of toxic Cr(VI) in an aqueous medium, and the optimum conditions of the process were reported. The removal process was dependant of solution pH where best results was achieved at pH = 2. Complete removal of chromium was achieved in less than 5 min by MMC700. The results were better fitted with pseudo-second-order kinetics and followed the Freundlich model isotherm. The maximum adsorption capacity was found to be 265.25 mg/g for MMC700, suggesting its application as an efficient, low-cost, and easily separable adsorbent for the toxic Cr(VI) removal process. The prepared adsorbents exhibited superior performance in the removal process compared to other agricultural wastes or biomass - derived adsorbents reported in literature.

Design, Cultivation, and Acoustic Analysis of a Building-Sized Mycelium Sculpture

Abstract This paper describes novel computational design, simulation, and fabrication techniques employed in the production of a large sound-absorbing sculpture called Phoenix, made entirely from mycelium-composite materials (myco-materials). Myco-materials are composites made of lignocellulosic agricultural waste fibers bound by fungal mycelium and are produced at commercial scale as alternatives for plastics, insulation foam, or styrene. Mycelium composite materials have known acoustical properties that can be tuned according to variables such as growing time, substrate type, substrate size, and density. The fabrication method for producing the Phoenix sculpture revisits how we build performative and formal complexity in the most economic and sustainable way. The results indicate the potential for grown materials to be used in retrofit projects, allowing rooms to be customized in various acoustical situations, such as music or speech.

Efficient caproic acid production from lignocellulosic biomass by bio-augmented mixed microorganisms

Producing caproic acid via carboxylate platform is an environmentally-friendly approach for treating lignocellulosic agricultural waste. However, its implementation is still challenged by low product yields and selectivity. A microbiome named cellulolytic acid-producing microbiome (DCB), proficient in producing cellulolytic acid, was successfully acquired and shows promise for producing high-level caproic acid. In this study, a bioaugmentation method utilizing Clostridium kluyveri is proposed to enhance caproic acid yield of DCB using rice straw. With exogenous ethanol, bioaugmentation with Clostridium kluyveri significantly improved the caproic acid concentration and selectivity by 7 times and 4.5 times, achieving 12.9 g/L and 55.1 %, respectively. The addition of Clostridium kluyveri introduced reverse β-oxidation pathway, a more efficient caproic acid production pathway. Meanwhile, bioaugmentation enriched the bacteria proficient in degrading straw and producing short-chain fatty acids, providing more substrates for caproic acid production. This study provides potential bioaugmentation strategies for optimizing caproic acid yield from lignocellulosic biomass.

Bioethanol Production from Characterized Pre-treated Sugarcane Trash and Jatropha Agrowastes

Low production costs and a potential feedstock supply make lignocellulosic ethanol (bioethanol) an important source of advanced biofuels. The physical and chemical preparation of this kind of lignocellulosic feedstock led to a high ethanol yield. In order to increase the yield of fermentable sugars, pretreatment is an essential process step that alters the lignocellulosic structure and improves its accessibility for the expensive hydrolytic enzymes. In this context, the chemical composition of sugarcane trash (dry leaves, green leaves, and tops) and jatropha (shell and seed cake) was determined to be mainly cellulose, hemicellulose, and lignin. Hydrogen peroxide and sodium hydroxide were applied in an attempt to facilitate the solubilization of lignin and hemicelluloses in five agrowastes. The extraction of hydrogen peroxide was much better than that of sodium hydroxide. A comparative study was done using SEM, EDXA, and FTIR to evaluate the difference between the two methods. The pretreated wastes were subjected to saccharification by commercial cellulases (30 IU/g substrate). The obtained glucose was fortified with nutrients and fermented statically by Saccharomyces cerevisiae F-307 for bioethanol production. The results revealed the bioethanol yields were 325.4, 310.8, 282.9, 302.4 and 264.0 mg ethanol/g treated agrowastes from green leaves of sugarcane, jatropha deolied seed cake, tops sugarcane, dry leaves of sugarcane, and jatropha shell, respectively. This study emphasizes the value of lignocellulosic agricultural waste as a resource for the production of biofuels as well as the significance of the extraction process.

Exploring microbial diversity in hot springs of Surajkund, India through 16S rRNA analysis and thermozyme characterization from endogenous isolates

Hot springs are a valuable source of biologically significant chemicals due to their high microbial diversity. To investigate the possibilities for industrial uses of these bacteria, researchers collected water and sediment samples from variety of hot springs. Our investigation employed both culture-dependent and culture-independent techniques, including 16S-based marker gene analysis of the microbiota from the hot springs of Surajkund, Jharkhand. In addition, we cultivated thermophilic isolates and screened for their ability to produce amylase, xylanase, and cellulase. After the optimized production of amylase the enzyme was partially purified and characterized using UPLC, DLS-ZP, and TGA. The retention time for the amylase was observed to be around 0.5 min. We confirmed the stability of the amylase at higher temperatures through observation of a steady thermo gravimetric profile at 400 °C. One of the thermophilic isolates obtained from the kund, demonstrated the potential to degrade lignocellulosic agricultural waste.

The Effect of Chemical Treated Spent Mushroom Substrate (SMS) on Lignocellulosic Content

A by-product of the mushroom industry, spent mushroom substrate (SMS) is primarily made of lignocellulosic agricultural waste. SMS contains cellulose (38–46.6%), lignin (25–34.5%), and hemicellulose (19–27.7%) and is nutrient-rich. The primary objectives of this study included the characterization of SMS, analysis of lignocellulosic content prior to and following pre-treatment, analysis of the effects of various NaOH concentrations with varying molarities (1.0 to 5.0 Molar), and analysis of surface morphology using a scanning electron microscope (SEM). The result that comparison between untreated and treated sample The result for untreated are contain high amount of lignin from 23.85% to 27.39% and for treated are amount reduce from 20.6% to 23.85%. The difference of NaOH concentration from 1.0 to 5.0 Molar, so the best pre-treatment is alkaline pre-treatment from 1.0 to 3.0 M are the best concentration to treat SMS sample from alkaline pre-treatment and proved sodium hydroxide pre-treatment as an effective method to reduce the hemicellulose and lignin contents. Images clearly showed how the pre-treatment could alter the biomass’s structural makeup and distort it, increasing the surface area that was open to enzymatic attack. The pre-treated SMS’s surface had numerous sporadic pores and cracks. The study’s findings demonstrated that SMS from the P. sajor-caju species has the potential to provide a new source of glucose for bioethanol production.

Improved saccharification of rice straw by removing phenolic compounds using a stable immobilized metagenome-derived laccase on sodium alginate-based hydrogel

Laccases can biodegrade lignocellulosic agricultural waste, which has a recalcitrant structure hindering industrial biomass hydrolysis. In the context of biomass decomposition, introduction of a stabilized enzyme with enhanced performance is of critical importance. This study aimed to stabilize laccase, obtained from tannery metagenome (PersiLac2) on sodium alginate-based hydrogels. The immobilized laccase remained stable in the acidic and alkaline pH ranges and preserved over 79.39 % of its initial activity at pH 4.0–9.0. Similarly, immobilized enzyme improved laccase activity at high temperatures, which is crucial in biorefinery processes, and the immobilized enzyme demonstrated 88.35 % activity at 80 ºC. The immobilization of laccase on hydrogels effectively prevented enzyme leaching and rendered it easier to separate and recycle, showing 58.74 % laccase activity after 15 cycles. The efficiency of immobilized PersiLac2 in enzymatic hydrolysis of rice straw was evaluated to enhance the generation of fermentable sugars, saccharification, and phenol reduction. Laccase treatment of rice straw resulted in an excellent saccharification yield and liberation of reducing sugars and removed 77.19 % of phenols during hydrolysis. The depolymerization effect of free and immobilized laccase on rice straw was investigated by FTIR and SEM analyses which confirmed efficient structural disruption by immobilization. The results indicated the potential of immobilized Persilac2 to degrade the compact wrap of lignin–carbohydrate complex in lignocellulosic substrates and its application in biomass-based industries.

Integrated lactic acid production from lignocellulosic agricultural wastes under thermal conditions

The production of lactic acid (LA) from agricultural wastes attracts great attention because of the sustainability and abundance of lignocellulosic feedstocks, as well as the increasing demand for biodegradable polylactic acid. In this study, we isolated a thermophilic strain Geobacillus stearothermophilus 2H-3 for use in robust production of L-(+)LA under the optimal conditions of 60 °C, pH 6.5, which were consistent with the whole-cell-based consolidated bio-saccharification (CBS) process. Sugar-rich CBS hydrolysates derived from various agricultural wastes, including corn stover, corncob residue, and wheat straw, were used as the carbon sources for 2H-3 fermentation by directly inoculating 2H-3 cells into the CBS system, without intermediate sterilization, nutrient supplementation, or adjustment of fermentation conditions. Thus, we successfully combined two whole-cell-based steps into a one-pot successive fermentation process to efficiently produce LA with high optical purity (99.5%), titer (51.36 g/L), and yield (0.74 g/gbiomass). This study provides a promising strategy for LA production from lignocellulose through CBS and 2H-3 fermentation integration.

Deeper insights into the synergy of material transformation, microbial network, and energy balance during pilot thermophilic and mesophilic dry anaerobic digestion systems

The present study investigated the synergistic characteristics between abiotic and biotic transformation with a view to improving the methane production efficiency of thermophilic and mesophilic sequencing batch dry anaerobic digestion (SBD-AD). The pilot scale experiment consisted of a lignocellulosic material based on a mixture of corn straw and cow dung. A leachate bed reactor was used for an AD cycle of 40 days. Several distinct differences are reflected in biogas (methane) production and VFA concentration and composition. A combination of first-order hydrolysis and a modified Gompertz model determined that the holocellulose (cellulose + hemicellulose) and maximum methanogenic efficiency at thermophilic temperatures were increased by 112.03 % and 90.09 %, respectively. Additionally, the methane production peak was extended by 3–5 days in comparison with that at mesophilic temperatures. The microbial community exhibited vastly different functional network relationships under the two temperature conditions (P < 0.05). The data indicate that Clostridales and Methanobacteria had preferable synergistic effects and that the metabolism of hydrophilic methanogens is necessary for the conversion of VFA to methane during thermophilic SBD-AD. The effect of mesophilic conditions on Clostridales was relative weakened, and acetophilic methanogens were mainly present. Moreover, simulation of the full-chain and operational strategy of SBD-AD engineering resulted in a decrease in heat energy consumption of 21.4–64.3 % at thermophilic temperatures and 30.0–90.0 % at mesophilic temperatures from winter to summer. Furthermore, the total net energy production of thermophilic SBD-AD was increased by 105.2 % in comparison with that at mesophilic temperatures, demonstrating strengthened energy recovery. Overall, raising the SBD-AD temperature to thermophilic levels has considerable application value for improving the treatment capacity of agricultural lignocellulosic waste.

Controlled Allocation of Aromatic/Aliphatic Substituents to Polysaccharides and Lignin in Sugarcane Bagasse via Successive Homogeneous Transesterification Using Ionic Liquid.

Lignocellulosic agricultural waste is an abundant renewable feedstock that can be utilized as a sustainable source of biomass-based plastics. Ideally, it is used without discarding any components, including cellulose, hemicellulose, and lignin. However, their utilization as lignocellulose-based plastics has been limited because of the low compatibility between the polysaccharides and lignin derivatives and the resulting poor mechanical properties of the final products. Here, we demonstrate a facile but highly controllable conversion of sugarcane bagasse into valuable thermoplastics by utilizing the excellent solubility and unique organocatalytic abilities of an ionic liquid, 1-ethyl-3-methylimidazolium acetate. In a homogeneous and one-pot chemical modification reaction system, the substitution ratio of an aromatic benzoyl group to an aliphatic hexanoyl group in the bagasse derivative was adjusted by the ratio of acyl reagents used. Moreover, the allocation of these two acyl groups to polysaccharide and lignin components in bagasse was successfully controlled only by exchanging the order of the acyl reagents introduced into the reaction system. The controlled introduction of the acyl groups into bagasse achieved a homogeneous polymer phase in the resultant multicomponent hot-pressed film, resulting in enhanced mechanical properties such as sufficient tensile strength (∼20 MPa) and excellent ductility with a high strain energy density (∼5 MJ m-3).

Extraction of Nanocellulose from Matured Coconut Husk

Nanocellulose is a promising nanomaterial that can be used in various applications such as reinforcements for composite films. Agricultural lignocellulosic wastes, such as coconut husks, offer great advantages as raw materials for nanocellulose extraction due to their abundance and economic viability. The aim of this study is to extract nanocellulose from matured coconut husk. Nanocellulose was extracted using sulfuric acid hydrolysis and characterized using Atomic Force Microscopy (AFM). Results showed that nanocellulose extracted from matured coconut husk has 2.26% yield with agglomerated, rod-shaped structures. An average aspect ratio of 3.16 ± 1.82 nm was also obtained.

Second-Generation Bio-Fuels: Strategies for Employing Degraded Land for Climate Change Mitigation Meeting United Nation-Sustainable Development Goals

Increased Greenhouse Gas (GHG) emissions from both natural and man-made systems contribute to climate change. In addition to reducing the use of crude petroleum’s derived fuels, and increasing tree-planting efforts and sustainable practices, air pollution can be minimized through phytoremediation. Bio-fuel from crops grown on marginal land can sustainably address climate change, global warming, and geopolitical issues. There are numerous methods for producing renewable energy from both organic and inorganic environmental resources (sunlight, air, water, tides, waves, and convective energy), and numerous technologies for doing the same with biomass with different properties and derived from different sources (food industry, agriculture, forestry). However, the production of bio-fuels is challenging and contentious in many parts of the world since it competes for soil with the growth of crops and may be harmful to the environment. Therefore, it is necessary to use wildlife management techniques to provide sustainable bio-energy while maintaining or even improving essential ecosystem processes. The second generation of bio-fuels is viewed as a solution to the serious issue. Agricultural lignocellulosic waste is the primary source of second-generation bio-fuel, possibly the bio-fuel of the future. Sustainable practices to grow biomass, followed by their holistic conversion into ethanol with desired yield and productivity, are the key concerns for employing renewable energy mix successfully. In this paper, we analyze the various types of bio-fuels, their sources, and their production and impact on sustainability.

Impact of eco-friendly chemical pretreatment on physicochemical and surface mechanical properties of sustainable lignocellulosic agricultural waste

This research aimed to investigate the impact of glycerol (Gly) and choline chloride (ChCl) pretreatments on physico-chemical and mechanical properties of rice husk (RH) at a submicron scale. Gly (75 wt%) and ChCl (25 wt%) were used to pretreat RH at 110 °C for 4 h in a water bath (150 rpm). Physico-chemical and surface mechanical (elastic modulus and hardness) properties of treated RH were determined and compared with untreated ones. The impacts of Gly and ChCl pretreatments on RH, surface morphology, structure, thermal stability, elastic modulus, and hardness were investigated using scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), x-rays diffractometry (XRD), thermogravimetric analysis (TGA) and nanoindentation technique, respectively. Experimental results depicted that pretreatment of RH with Gly and ChCl produced cellulosic-rich fiber, increase crystallinity, and enhanced thermal stability. In contrast to the untreated (35 %) RH, the ChCl and Gly-treated RH had cellulose contents of 49 % and 45 %, respectively. The degree of crystallinity was increased after the treatment of RH with 37 % and 35 % in ChCl RH, respectively, as compared to the untreated one. Elastic modulus and hardness of ChCl-treated RH were decreased by 67 % and 70 %, respectively, compared to the untreated one. Similarly, reductions in elastic modulus and hardness were noted in the case of Gly treatment. According to current research, lignocellulosic biomass can be pretreated with green solvents to produce cellulosic-rich fiber for engineered composite applications.

Bioconversion of non-food corn biomass to polyol esters of fatty acid and single-cell oils

BackgroundLignocellulose is a valuable carbon source for the production of biofuels and biochemicals, thus having the potential to substitute fossil resources. Consolidated bio-saccharification (CBS) is a whole-cell-based catalytic technology previously developed to produce fermentable sugars from lignocellulosic agricultural wastes. The deep-sea yeast strain Rhodotorulapaludigena P4R5 can produce extracellular polyol esters of fatty acids (PEFA) and intracellular single-cell oils (SCO) simultaneously. Therefore, the integration of CBS and P4R5 fermentation processes would achieve high-value-added conversion of lignocellulosic biomass.ResultsThe strain P4R5 could co-utilize glucose and xylose, the main monosaccharides from lignocellulose, and also use fructose and arabinose for PEFA and SCO production at high levels. By regulating the sugar metabolism pathways for different monosaccharides, the strain could produce PEFA with a single type of polyol head. The potential use of PEFA as functional micelles was also determined. Most importantly, when sugar-rich CBS hydrolysates derived from corn stover or corncob residues were used to replace grain-derived pure sugars for P4R5 fermentation, similar PEFA and SCO productions were obtained, indicating the robust conversion of non-food corn plant wastes to high-value-added glycolipids and lipids. Since the produced PEFA could be easily collected from the culture via short-time standing, we further developed a semi-continuous process for PEFA production from corncob residue-derived CBS hydrolysate, and the PEFA titer and productivity were enhanced up to 41.1 g/L and 8.22 g/L/day, respectively.ConclusionsHere, we integrated the CBS process and the P4R5 fermentation for the robust production of high-value-added PEFA and SCO from non-food corn plant wastes. Therefore, this study suggests a feasible way for lignocellulosic agro-waste utilization and the potential application of P4R5 in industrial PEFA production.

Anti-Inflammatory, Anti-Bacterial, and Anti-Fungal Activity of Oligomeric Proanthocyanidins and Extracts Obtained from Lignocellulosic Agricultural Waste.

It has now been proven that many pathogens that cause infections and inflammation gradually mutate and become resistant to antibiotics. Chemically synthesized drugs treating inflammation most often only affect symptoms, but side effects could lead to the failure of human organs' functionality. On the other hand, plant-derived natural compounds have a long-term healing effect. It was shown that sea buckthorn (SBT) twigs are a rich source of biologically active compounds, including oligomeric proanthocyanidins (PACs). This study aimed to assess the anti-pathogenic and anti-inflammatory activity of water/ethanol extracts and PACs obtained from the lignocellulosic biomass of eight SBT cultivars. The anti-pathogenic activity of extracts and PACs was studied against pathogenic bacteria Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Bacillus cereus and fungus Candida albicans in 96-well plates by the two-fold serial broth microdilution method. The anti-bacterial activity of purified PACs was 4 and 10 times higher than for water and water/ethanol extracts, respectively, but the extracts had higher anti-fungal activity. Purified PACs showed the ability to reduce IL-8 and IL-6 secretion from poly-I:C-stimulated peripheral blood mononuclear cells. For the extracts and PACs of SBT cultivar 'Maria Bruvele' in the concentration range 0.0313-4.0 mg/mL, no toxic effect was observed.

Optimization of Adsorption Parameters for Removal of Cationic Dyes on Lignocellulosic Agricultural Waste Modified by Citric Acid: Central Composite Design

Barley straw (BS-C) and corn stalks (CS-C) modified by citric acid are hopeful adsorbents for the removal of cationic dyes from aqueous solutions. Optimization of adsorption factors to improve removal of methylene blue (MB) and malachite green (MG) on BC-C and CS-C was carried out by response surface methodology with central composite design. The effect of pH, time, dye concentration, and adsorbent dose on the removal efficiency of cationic dyes was investigated. The experimental data were in good agreement with the predicted data obtained by mathematical models. Accordingly, the maximum MB removal efficiency on BS-C of 97% was achieved with a pH of 6.4, time of 50 min, an adsorbent dose of 11 g L−1, and an initial MB concentration of 26 mg L−1; the maximum MG removal efficiency on BS-C of 95% was achieved with a pH of 7.2, time of 60 min, an adsorbent dose of 14 g L−1, and an initial MG concentration of 24 mg L−1; the maximum MB removal efficiency on CS-C of 97% was achieved with a pH of 6.5, time of 45 min, an adsorbent dose of 11 g L−1, and an initial MB concentration of 20 mg L−1; the maximum MG removal efficiency on CS-C of 94% was achieved with a pH of 6.6, time of 50 min, an adsorbent dose of 12 g L−1, and an initial MG concentration of 24 mg L−1.

Lignocellulosic Biomass as Agricultural Bioresource and Input to the Circular Economy

Given the global economic issues and environmental pollution, there is a growing interest in research addressing the use of biomasses resulting from agricultural production. One main category of biomass components is lignin, the use of plant waste in the pulp industry being one of the ways in avoiding additional deforestation by suppling inputs for the paper industry. The implementation of a strategy for capitalizing the potential of renewable sources, as, but not limited to, paper production, provides the appropriate framework for decision on renewable alternatives and inclusion in the acquis domains in Romania. The present study analyzed the potential use of waste obtained from field crops, mainly annual, as wheat, sunflower, maize, soy, rape, rye, barley, sorghum, rice, to produce paper. Biomass/waste from field crops is a promising source for paper, primarily because it is renewable and has the potential to exploit over 7 million hectares of arable land, with annual use. The diversity of pedoclimatic conditions in Romania makes possible the cultivation of a wider range of species and, within them, a multitude of varieties and hybrids, with variable amounts of lignocellulosic agricultural waste. In addition, accidental years as 2022, the year with the worst drought in Europe in the last 500 years, reshaped the need of valorizing any available biomass, regardless of the production of the main crop. Our calculations show that for a paper containing 28% of renewable cellulose, with the wheat straws collected from Romania in 2019, 9633.31 thousand tons of paper would have been obtained, with an average per hectare of 2786.62 kg of paper. Our analysis shows the opportunity of using lignocellulosic agricultural waste for use as a raw material for paper production. A throughout analysis is needed in the context of extreme droughts experienced recently, to show which valorization of by-products is the most economically justified.

Waste apple biomass conversion to 5-HMF over tin doped sulfonated activated carbon as a catalyst

Utilisation of lignocellulosic agricultural waste biomass could provide a carbon net zero alternative for production of valuable chemicals. However, the progress is hindered because there's no catalyst to carry out a selective and efficient conversion process. In this study a new promising catalyst for this challenging conversion is reported. It is prepared by sulfonation of activated carbon followed by the impregnation of tin (Sn). The catalyst has been characterized by NH3-TPD, FTIR, XRF and N2 physisorption. The catalyst was tested at 120 °C for the conversion of model carbohydrate mixtures prepared in the laboratory and real biomass mixtures of apple fruit biomass waste. The catalytic performance for the conversion of a model carbohydrate mixture resulted in a 5-hydroxymethylfurfural (5-HMF) yield of 30% in 80 min. On the other hand, catalytic testing of real apple pomace biomass showed a 5-HMF yield of 24% in 80 min. The Sn catalyst was also shown to maintain the 5-HMF yield in recycle experiments using a model carbohydrate mixture. Conversely, stability was lower when the Sn catalyst was tested in real apple pomace mixture, which is likely due to the presence of other impurities.

Green Extraction Method of Cellulose Fibers from Oil Palm Empty Fruit Bunches

Oil palm empty fruit bunches (OPEFB) is one of the major biomass wastes produced from palm oil extraction process. Due to high cellulose content in OPEFB, the cellulose fibers in OPEFB can be extracted and utilized in versatile applications as a sustainable process technology development. Among multiple pre-treatment processes, chemical pre-treatment is most efficient for the removal of hemicellulose and lignin in extracting high purity cellulose from lignocellulosic biomass. With the undisputed importance of green technology for the progress of our society, it is vital to engage and leverage on green technology in chemical pre-treatment method for extracting cellulose from OPEFB. The objective of this study is to explore a green extraction method for cellulose from OPEFB using low concentration and eco-friendly chemicals. Fourier transform infrared spectroscopy and field emission scanning electron microscope was used to detect the functional groups and to observe the surface morphology of OPEFB, de-waxed OPEFB fibers, delignified OPEFB fibers, acid hydrolyzed OPEFB fibers, and OPEFB extracted cellulose fibers at different stages in confirming the removal of wax, lignin, and hemicellulose from OPEFB extracted cellulose at the end of the extraction process. Crystallinity index increased from 28% for OPEFB to 72% for the OPEFB extracted cellulose, affirms the degradation of OPEFB’s amorphous structure and transforms into higher crystallinity structure. This work has successfully developed a green extraction method for OPEFB cellulose fibers as part of sustainable process technology which would promote the utilization of lignocellulosic agricultural waste from palm oil industry in various applications.