Oil palm trunk (OPT) is one of the most promising lignocellulosic bioresources. To develop effective biodegradation, thermophilic, anaerobic microorganisms were screened from bovine manure compost using fibrillated OPT (f-OPT) pretreated by wet disk milling as the substrate. One thermophilic, anaerobic bacterium, strain CL-2, whose 16S rDNA gene has 98.6% sequence identity with that of Caldicoprobacter faecale DSM 20678T, exhibited high degradation activity (32.7% reduction in total dry solids of f-OPT). Strain CL-2 did not use cellulose as a carbon source, but used hemicelluloses such as xylan, arabinoxylan, starch and pectin at 70 °C. Phylogenetic and morphologic analyses and the polysaccharide use suggest that CL-2 may be classified as a novel species of Caldicoprobacter, named Caldicoprobacter sp. CL-2. To characterize enzymatic activities of CL-2, extracellular enzymes were prepared from culture broth using beechwood xylan as the carbon source. The extracellular enzymes showed high xylanase activity, but low cellulase activity, suggesting that f-OPT degradation may depend on xylanase activity. To understand the xylanase system of CL-2, a major xylanase was cloned and characterized. The xylanase (CalXyn11A) had a modular structure consisting of a glycoside hydrolase (GH) family-11 domain and a family 36 carbohydrate-binding module. CalXyn11A did not show f-OPT degradation activity, but a strong synergistic effect was observed when CalXyn11A was added to the extracellular enzyme preparation. These results indicate that, rather than working alone, CalXyn11A has an important role in enhancing total lignocellulose degradation activity by cooperation with other GHs.
Lignocellulosic biomass dedicated to bioethanol production usually contains pentoses and inhibitory compounds such as furfural that are not well tolerated by Saccharomyces cerevisiae. Thus, S. cerevisiae strains with the capability of utilizing both glucose and xylose in the presence of inhibitors such as furfural are very important in industrial ethanol production. Under the synergistic conditions of transaldolase (TAL) and alcohol dehydrogenase (ADH) overexpression, S. cerevisiae MT8-1X/TAL-ADH was able to produce 1.3-fold and 2.3-fold more ethanol in the presence of 70 mM furfural than a TAL-expressing strain and a control strain, respectively. We also tested the strains' ability by mimicking industrial ethanol production from hemicellulosic hydrolysate containing fermentation inhibitors, and ethanol production was further improved by 16% when using MT8-1X/TAL-ADH compared to the control strain. Transcript analysis further revealed that besides the pentose phosphate pathway genes TKL1 and TAL1, ADH7 was also upregulated in response to furfural stress, which resulted in higher ethanol production compared to the TAL-expressing strain. The improved capability of our modified strain was based on its capacity to more quickly reduce furfural in situ resulting in higher ethanol production. The co-expression of TAL/ADH genes is one crucial strategy to fully utilize undetoxified lignocellulosic hydrolysate, leading to cost-competitive ethanol production.
Non-healing wounds have placed an enormous stress on both patients and healthcare systems worldwide. Severe complications induced by these wounds can lead to limb amputation or even death and urgently require more effective treatments. Electrospun scaffolds have great potential for improving wound healing treatments by providing controlled drug delivery. Previously, we developed fibrous scaffolds from complex carbohydrate polymers [i.e. chitin-lignin (CL) gels]. However, their application was limited by solubility and undesirable burst drug release. Here, a coaxial electrospinning is applied to encapsulate the CL gels with polycaprolactone (PCL). Presence of a PCL shell layer thus provides longer shelf-life for the CL gels in a wet environment and sustainable drug release. Antibiotics loaded into core-shell fibrous platform effectively inhibit both gram-positive and -negative bacteria without inducting observable cytotoxicity. Therefore, PCL coated CL fibrous gel platforms appear to be good candidates for controlled drug release based wound dressing applications.
Lignification of the plant cell wall could serve as the first line of defense against pathogen attack, but the molecular mechanisms of virulence and disease between oil palm and Ganoderma boninense are poorly understood. This study presents the biochemical, histochemical, enzymology and gene expression evidences of enhanced lignin biosynthesis in young oil palm as a response to G. boninense (GBLS strain). Comparative studies with control (T1), wounded (T2) and infected (T3) oil palm plantlets showed significant accumulation of total lignin content and monolignol derivatives (syringaldehyde and vanillin). These derivatives were deposited on the epidermal cell wall of infected plants. Moreover, substantial differences were detected in the activities of enzyme and relative expressions of genes encoding phenylalanine ammonia lyase (EC 4.3.1.24), cinnamate 4-hydroxylase (EC 1.14.13.11), caffeic acid O-methyltransferase (EC 2.1.1.68) and cinnamyl alcohol dehydrogenase (CAD, EC 1.1.1.195). These enzymes are key intermediates dedicated to the biosynthesis of lignin monomers, the guaicyl (G), syringyl (S) and ρ-hydroxyphenyl (H) subunits. Results confirmed an early, biphasic and transient positive induction of all gene intermediates, except for CAD enzyme activities. These differences were visualized by anatomical and metabolic changes in the profile of lignin in the oil palm plantlets such as low G lignin, indicating a potential mechanism for enhanced susceptibility toward G. boninense infection.
Ability of two strains of Aspergillus terreus (ATCC 74135 and ATCC 20542) for production of lovastatin in solid state fermentation (SSF) using rice straw (RS) and oil palm frond (OPF) was investigated. Results showed that RS is a better substrate for production of lovastatin in SSF. Maximum production of lovastatin has been obtained using A. terreus ATCC 74135 and RS as substrate without additional nitrogen source (157.07 mg/kg dry matter (DM)). Although additional nitrogen source has no benefit effect on enhancing the lovastatin production using RS substrate, it improved the lovastatin production using OPF with maximum production of 70.17 and 63.76 mg/kg DM for A. terreus ATCC 20542 and A. terreus ATCC 74135, respectively (soybean meal as nitrogen source). Incubation temperature, moisture content, and particle size had shown significant effect on lovastatin production (P < 0.01) and inoculums size and pH had no significant effect on lovastatin production (P > 0.05). Results also have shown that pH 6, 25°C incubation temperature, 1.4 to 2 mm particle size, 50% initial moisture content, and 8 days fermentation time are the best conditions for lovastatin production in SSF. Maximum production of lovastatin using optimized condition was 175.85 and 260.85 mg/kg DM for A. terreus ATCC 20542 and ATCC 74135, respectively, using RS as substrate.
This study was driven by the stringent environmental legislation concerning the consumption and utilization of eco-friendly materials. Within this context, this paper aimed to examine the characteristics of starch and fibres from the Dioscorea hispida tuber plant to explore their potential as renewable materials. The extraction of the Dioscorea hispida starch and Dioscorea hispida fibres was carried out and the chemical composition, physical, thermal, morphological properties, and crystallinity were studied. The chemical composition investigations revealed that the Dioscorea hispida starch (DHS) has a low moisture t (9.45%) and starch content (37.62%) compared to cassava, corn, sugar palm, and arrowroot starches. Meanwhile, the Dioscorea hispida fibres (DHF) are significantly low in hemicellulose (4.36%), cellulose (5.63%), and lignin (2.79%) compared to cassava, corn hull and sugar palm. In this investigation the chemical, physical, morphological and thermal properties of the Dioscorea hispida fibre and Dioscorea hispida starch were examined by chemical composition investigation, scanning electron microscopy (SEM), particle size distribution, thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), and Fourier transform infrared (FTIR), respectively. It was found that Dioscorea hispida waste is promising alternative biomass and sustainable material with excellent potential as a renewable filler material for food packaging applications.
In this study, agriculture biomass was used to remove dissolved organic matter from peat swamp runoff. The functional groups and morphological properties of 6 tropical agriculture biomasses (coconut husk, rice husk, empty fruit bunch, sago hampas, saw dust and banana trunk) in their raw and citric acid–treated states were examined. The Fourier transform infrared (FTIR) spectra showed that various biomasses were typically characterised with lignocellulosic compounds. The spectra analysis further demonstrated that citric acid treatment resulted in the dissolution of lignin and hemicelluloses to various extents where carboxyl groups were also introduced. These changes hypothetically suggest improved adsorption ability. Treatment of peat swamp runoff with various untreated biomasses showed no adsorption. With the modified biomass, adsorption was evidenced, with rice husk illustrating the highest removal efficiency of 60% to 65%.The biosorbent can be used in the water treatment process especially for treating water with a high dissolved organic matter content. The spent sorbent can be subsequently applied as a soil conditioner as the dissolved organic fraction, commonly known as humic matter, possesses important agricultural value.
There is growing interest in the use of unconventional feed ingredients containing higher dietary fiber for pig production due to increasing prices of cereal grains and the potential health benefits of dietary fiber on host animals. This study aimed to gain insight into the community-wide microbiome population between the Chinese native Lantang pigs and the commercial Duroc pigs to uncover the microbiological mechanisms for the degradation capacity of fiber in pigs. Utilizing the metagenomics approach, we compared the phylogeny and functional capacity of the fecal microbiome from approximately 150-day-old female Lantang and Duroc pigs fed a similar diet. The structure of the fecal microbial community from the two pig breeds was different at the genus level; the number of genes associated with fiber degradation was higher in Lantang pigs. Further analysis and prediction of their functions from the fecal microbiomes of the two pig breeds revealed that the degradation capacities of fiber, branched chain fatty acids, and oligosaccharides were higher in Lantang pigs. The ability of lignocellulose bonding modules and the transport capacities of xylose, L-arabinose, ribose and methyl galactose were also higher in Lantang pigs. Similarly, the metabolic capacities of xylose, ribose, and fucose and the potential effectiveness of the tricarboxylic acid cycle (TCA) and gene abundance in the hydrogen sink pathway were higher in the fecal microbiome from Lantang pigs. Lantang pigs have a higher capacity to utilize dietary fiber than Duroc pigs, and the differences in the capability to utilize dietary fiber between the indigenous and commercial pigs could be differences in the composition and biological function of the gut microbiota.
Biological fermentation of Rhizopus oryzae was introduced to extract cellulose nanofibre from durian skin fibre (DSF).
The diameter of the extracted durian skin nanofibre (DSNF) was in the range of 49-81 nm. The changes of chemical
composition of DSNF were clearly seen after evaluated via TAPPI standard test methods. Verification via Fourier transform
infrared (FTIR) confirmed the deduction of hemicelluloses and lignin in DSNF in the range of 1200 to 1000 cm-1. X-ray
diffraction (XRD) demonstrated increment in the crystallinity from 58.3 to 72.2% after biological fermentation. DSNF was
then incorporated into polylactic acid (PLA) via extrusion and injection moulding processes. The effect of 1-5 wt. % DSNF
content on PLA biocomposites was investigated for its mechanical and thermal properties. The presence of only 1 wt. %
improved the tensile and impact strength by 14.1 MPa and 33.1 kJ/m2
, respectively. The thermal properties of PLA-1DSNF
biocomposite also recorded higher thermal stability, glass transition temperature (Tg
), crystallization temperature (Tc
)
and melting temperature (Tm). Additionally, from the DMA, it was determined that PLA-1DSNF possessed lower storage
modulus and loss modulus, as well as low energy dissipation.
In the present work, four types of newly chosen municipal solid wastes (Panax ginseng, spent tea residue, waste cotton cloth, and old corrugated cardboard) were studied as the promising sources for nanocellulose, which has efficiently re-engineered the structure of waste products into highly valuable nanocellulose materials. The nanocellulose was produced directly via a facile one-pot oxidative hydrolysis process by using H2O2/Cr(NO3)3 solution as the bleaching agent and hydrolysis medium under acidic condition. The isolated nanocellulose products were well-characterized in terms of chemical composition, product yield, morphological structure and thermal properties. The study has found that the crystallinity index of the obtained nanocellulose products were significantly higher (62.2-83.6%) than that of its starting material due to the successive elimination of lignin, hemicellulose and amorphous regions of cellulose, which were in good agreement with the FTIR analysis. The evidence of the successful production of nanocellulose was given by TEM observation which has revealed the fibril widths were ranging from 15.6 to 46.2nm, with high cellulose content (>90%), depending on the cellulosic origin. The physicochemical properties of processed samples have confirmed that the isolation of high purity nanocellulose materials from different daily spent products is possible. The comparative study can help to provide a deep insight on the possibility of revalorizing the municipal solid wastes into nanocellulose via the simple and versatile one-pot isolation system, which has high potential to be used in commercial applications for sustainable development.
This study was directed at the understanding of the function of CCoAOMT isolated from Acacia auriculiformis x Acacia mangium. Full length cDNA of the Acacia hybrid CCoAOMT (AhCCoAOMT) was 1024-bp long, containing 750-bp coding regions, with one major open reading frame of 249 amino acids. On the other hand, full length genomic sequence of the CCoAOMT (AhgflCCoAOMT) was 2548 bp long, containing three introns and four exons with a 5' untranslated region (5'UTR) of 391 bp in length. The 5'UTR of the characterized CCoAOMT gene contains various regulatory elements. Southern analysis revealed that the Acacia hybrid has more than three copies of the CCoAOMT gene. Real-time PCR showed that this gene was expressed in root, inner bark, leaf, flower and seed pod of the Acacia hybrid. Downregulation of the homologous CCoAOMT gene in tobacco by antisense (AS) and intron-containing hairpin (IHP) constructs containing partial AhCCoAOMT led to reduction in lignin content. Expression of the CCoAOMT in AS line (pART-HAS78-03) and IHP line (pART-HIHP78-06) was reduced respectively by 37 and 75% compared to the control, resulting in a decrease in the estimated lignin content by 24 and 56%, respectively. AhCCoAOMT was found to have altered not only S and G units but also total lignin content, which is of economic value to the pulp industry. Subsequent polymorphism analysis of this gene across eight different genetic backgrounds each of A. mangium and A. auriculiformis revealed 47 single nucleotide polymorphisms (SNPs) in A. auriculiformis CCoAOMT and 30 SNPs in A. mangium CCoAOMT.
In this work, the oil palm empty fruit bunch (EFB) fiber was used as a source of lignocellulosic filler to fabricate a novel type of cost effective biodegradable composite, based on the aliphatic aromatic co-polyester poly(butylene adipate-co-terephtalate) PBAT (Ecoflex™), as a fully biodegradable thermoplastic polymer matrix. The aim of this research was to improve the new biocomposites' performance by chemical modification using succinic anhydride (SAH) as a coupling agent in the presence and absence of dicumyl peroxide (DCP) and benzoyl peroxide (BPO) as initiators. For the composite preparation, several blends were prepared with varying ratios of filler and matrix using the melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 (wt %) and characterized. The effects of fiber loading and coupling agent loading on the thermal properties of biodegradable polymer composites were evaluated using thermal gravimetric analysis (TGA). Scanning Electron Microscopy (SEM) was used for morphological studies. The chemical structure of the new biocomposites was also analyzed using the Fourier Transform Infrared (FTIR) spectroscopy technique. The PBAT biocomposite reinforced with 40 (wt %) of EFB fiber showed the best mechanical properties compared to the other PBAT/EFB fiber biocomposites. Biocomposite treatment with 4 (wt %) succinic anhydride (SAH) and 1 (wt %) dicumyl peroxide (DCP) improved both tensile and flexural strength as well as tensile and flexural modulus. The FTIR analyses proved the mechanical test results by presenting the evidence of successful esterification using SAH/DCP in the biocomposites' spectra. The SEM micrograph of the tensile fractured surfaces showed the improvement of fiber-matrix adhesion after using SAH. The TGA results showed that chemical modification using SAH/DCP improved the thermal stability of the PBAT/EFB biocomposite.
The gene encoding a cellobiohydrolase 7B (CBH7B) of the thermophilic fungus Thielavia terrestris was identified, subcloned, and expressed in Pichia pastoris. CBH7B encoded 455 amino acid residues with a molecular mass of 51.8 kDa. Domain analysis indicated that CBH7B contains a family 7 glycosyl hydrolase catalytic core but lacks a carbohydrate-binding module. Purified CBH7B exhibited optimum catalytic activity at pH 5.0 and 55 °C with 4-methylumbelliferryl-cellobioside as the substrate and retained 85% of its activity following 24 H incubation at 50 °C. Despite the lack of activity toward microcrystalline substrates, this enzyme worked synergistically with the commercial enzyme cocktail Cellic(®) CTec2 to enhance saccharification by 39% when added to a reaction mixture containing 0.25% alkaline pretreated oil palm empty fruit bunch (OPEFB). Attenuated total reflectance Fourier transform infrared spectroscopy suggested a reduction of lignin and crystalline cellulose in OPEFB samples supplemented with CBH7B. Scanning electron microscopy revealed greater destruction extent of OPEFB strands in samples supplemented with CBH7B as compared with the nonsupplemented control. Therefore, CBH7B has the potential to complement commercial enzymes in hydrolyzing lignocellulosic biomass.
Deep Eutectic Solvents (DESs) have recently emerged as a new generation of ionic liquids for lignocellulose pretreatment. However, DESs contain salt components which tend to inactivate cellulase in the subsequent saccharification process. To alleviate this problem, it is necessary to evaluate the applicability of the DESs-Cellulase system. This was accomplished in the present study by first studying the stability of cellulase in the presence of selected DESs followed by applicability evaluation based on glucose production, energy consumption and kinetic performance. Results showed that the cellulase was able to retain more than 90% of its original activity in the presence of 10% (v/v) for glycerol based DES (GLY) and ethylene glycol based DES (EG). Furthermore, both DESs system exhibited higher glucose percentage enhancement and lower energy consumption as compared to diluted alkali system. Among the two DESs studied, EG showed comparatively better kinetic performance.
Palm Oil Mill Effluent (POME) treatment has always been a topic of research in Malaysia. This effluent that is extremely rich in organic content needs to be properly treated to minimize environmental hazards before it is released into watercourses. The main aim of this work is to evaluate the potential of applying natural, chemically and thermally modified banana peel as sorbent for the treatment of biologically treated POME. Characteristics of these sorbents were analyzed with BET surface area and SEM. Batch adsorption studies were carried out to remove color, total suspended solids (TSS), chemical oxygen demand (COD), tannin and lignin, and biological oxygen demand (BOD) onto natural banana peel (NBP), methylated banana peel (MBP), and banana peel activated carbon (BPAC) respectively. The variables of pH, adsorbent dosage, and contact time were investigated in this study. Maximum percentage removal of color, TSS, COD, BOD, and tannin and lignin (95.96%, 100%, 100%, 97.41%, and 76.74% respectively) on BPAC were obtained at optimized pH of 2, contact time of 30 h and adsorbent dosage of 30 g/100 ml. The isotherm data were well described by the Redlich-Peterson isotherm model with correlation coefficient of more than 0.99. Kinetic of adsorption was examined by Langergren pseudo first order, pseudo second order, and second order. The pseudo second order was identified to be the governing mechanism with high correlation coefficient of more than 0.99.
The potential of Parthenium sp. as a feedstock for enzymatic saccharification was investigated by using chemical and biological pretreatment methods. Mainly chemical pretreatments (acid and alkali) were compared with biological pretreatment with lignolytic fungi Marasmiellus palmivorus PK-27. Structural and chemical changes as well as crystallinity of cellulose were examined through scanning electron microscopy, fourier transform infra red and X-ray diffraction analysis, respectively after pretreatment. Total reducing sugar released during enzymatic saccharification of pretreated substrates was also evaluated. Among the pretreatment methods, alkali (1% NaOH) treated substrate showed high recovery of acid perceptible polymerised lignin (7.53 ± 0.5 mg/g) and significantly higher amount of reducing sugar (513.1 ± 41.0 mg/gds) compared to uninoculated Parthenium (163.4 ± 21.2) after 48 h of hydrolysis. This is the first report of lignolytic enzyme production from M. palmivorus, prevalent in oil palm plantations in Malaysia and its application in biological delignification of Parthenium sp. Alkali (1% NaOH) treatment proves to be the suitable method of pretreatment for lignin recovery and enhanced yield of reducing sugar which may be used for bioethanol production from Parthenium sp.
This study was undertaken to compare the chemical properties and yields of pineapple leaf residue (PLR) char produced by field burning (CF) with that produced by a partial combustion of air-dried PLR at 340 °C for 3 h in a furnace (CL). Higher total C, lignin content, and yield from CL as well as the presence of aromatic compounds in the Fourier Transform Infrared spectra of the char produced from CL suggest that the CL process was better in sequestering C than was the CF process. Although the C/N ratio of char produced from CL was low indicating a high N content of the char, the C in the char produced from CL was dominated by lignin suggesting that the decomposition of char produced from CL would be slow. To sequester C by char application, the PLR should be combusted in a controlled process rather than by burning in the field.
This work presents the pretreatment of oil palm fronds (OPF) using hot compressed water (HCW) to enhance sugar recovery in enzymatic hydrolysis. A central, composite rotatable design was used to optimize the effect of reaction temperature, reaction time and liquid-solid ratio on the pretreatment process. All variables were found to significantly affect the glucose yield. A quadratic polynomial equation was used to model glucose yield by multiple regression analysis, using response surface methodology (RSM). Using a 10 bar pressurized reactor, the optimum conditions for pretreatment of OPF were found at 178 degrees C, 11.1 min and a liquid-solid ratio of 9.6. The predicted glucose yield was 92.78 wt.% at the optimum conditions. Experimental verification of the optimum conditions gave a glucose yield in good agreement with the estimated value of the model.
MicroRNAs (miRNAs) play critical regulatory roles by acting as sequence specific guide during secondary wall formation in woody and non-woody species. Although thousands of plant miRNAs have been sequenced, there is no comprehensive view of miRNA mediated gene regulatory network to provide profound biological insights into the regulation of xylem development. Herein, we report the involvement of six highly conserved amg-miRNA families (amg-miR166, amg-miR172, amg-miR168, amg-miR159, amg-miR394, and amg-miR156) as the potential regulatory sequences of secondary cell wall biosynthesis. Within this highly conserved amg-miRNA family, only amg-miR166 exhibited strong differences in expression between phloem and xylem tissue. The functional characterization of amg-miR166 targets in various tissues revealed three groups of HD-ZIP III: ATHB8, ATHB15, and REVOLUTA which play pivotal roles in xylem development. Although these three groups vary in their functions, -psRNA target analysis indicated that miRNA target sequences of the nine different members of HD-ZIP III are always conserved. We found that precursor structures of amg-miR166 undergo exhaustive sequence variation even within members of the same family. Gene expression analysis showed three key lignin pathway genes: C4H, CAD, and CCoAOMT were upregulated in compression wood where a cascade of miRNAs was downregulated. This study offers a comprehensive analysis on the involvement of highly conserved miRNAs implicated in the secondary wall formation of woody plants.
The production of lignin from empty fruit bunch (EFB) has been carried out using liquefaction method with 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid (IL), in presence of sulfuric acid (H2SO4) as a catalyst. Response surface methodology (RSM) based on a factorial Central Composite Design (CCD) was employed to identify the optimum condition for lignin yield. The result indicated that the second order model was adequate for all the independent variables on the response with R(2)=0.8609. The optimum temperature, time, ionic liquid to EFB ratio, and catalyst concentration were 150.5 °C, 151 min, 3:1 wt/wt and 4.73 wt%, respectively for lignin yield=26.6%. The presence of lignin liquefied product was confirmed by UV-Vis and FTIR analysis. It was also demonstrated lignin extraction from lignocellulosic using recycled IL gave sufficient performance.