Thidarat Nimchua - Academia.edu (original) (raw)

Papers by Thidarat Nimchua

Industrial Crops and Products, Feb 1, 2022

In this study, cellulose was obtained from sugarcane bagasse (SCB) and treated with xylanase to r... more In this study, cellulose was obtained from sugarcane bagasse (SCB) and treated with xylanase to remove residual noncellulosic polymers (hemicellulose and lignin) to improve its dyeability. The cellulose fibers were dyed with natural dye solutions extracted from the heart wood of Ceasalpinia sappan Linn. and Artocarpus heterophyllus Lam. Fourier-transform infrared (FTIR) spectroscopy, Raman analysis, and whiteness index (WI) indicated successful extraction of cellulose by eliminating hemicellulose and lignin. The FTIR analysis of the dyed fibers confirmed successful interaction between natural dyes and cellulose fibers. The absorption (K) and scattering (S) coefficient (K/S) values of the dyed fibers increased in cellulose treated with xylanase before dyeing. Scanning electron microscopy (SEM) analysis showed that the surface of alkaline-bleached fibers (AB-fibers) was smoother than alkaline-bleached xylanase fibers (ABX-fibers), and the presence of dye particles on the surface of dyed fibers was confirmed by energy-dispersive spectrometry (EDS) analysis. The X-ray diffraction (XRD) revealed a higher crystallinity index (CrI), and thermal gravimetric analysis (TGA) also presented higher thermal stability in the dyed fibers with good colorfastness to light. Therefore, xylanase treatment and natural dyes can enhance dyeability and improve the properties of cellulose for various industrial applications.

Fermentation, 2022

Superoxide dismutase (SOD) is crucial antioxidant enzyme that plays a role in protecting cells ag... more Superoxide dismutase (SOD) is crucial antioxidant enzyme that plays a role in protecting cells against harmful reactive oxygen species (ROS) which are generated inside cells. Due to its functionality, SOD is used in many applications. In this study, Saccharomyces cerevisiae TBRC657 was selected as the SOD producer due to its high SOD production. After investigating an optimized medium, the major components were found to be molasses and yeast extract, which improved SOD production up to 3.97-fold compared to a synthetic medium. In addition, the optimized medium did not require any induction, which makes it suitable for applications in large-scale production. The SOD formulation was found to increase the stability of the conformational structure and prolong shelf-life. The results show that 1.0% (w/w) trehalose was the best additive, in giving the highest melting temperature by the DSF method and maintaining its activity at more than 80% after storage for 6 months. The obtained SOD wa...

Effect of pH on EndoPG activity. Effect of temperature on EndoPG activity. Effect of pH on stabil... more Effect of pH on EndoPG activity. Effect of temperature on EndoPG activity. Effect of pH on stability of EndoPG activity. Effect of temperature (20–60 °C) on stability of EndoPG activity. RAW data of enzyme activities were calculated and showed as volumetric activity (U/ml) and % relative activity. Standard deviations (SD) were calculated from volumetric activity. (XLS 40 kb)

Advances in life sciences, 2014

Glycoside hydrolase family 43 (GH43) from Paenibacillus curdlanolyticus strain B-6 (Xyl43B6) was ... more Glycoside hydrolase family 43 (GH43) from Paenibacillus curdlanolyticus strain B-6 (Xyl43B6) was preformed heterologous expression in Escherichia coli. Enzymatic function determination revealed that Xyl43B6 exhibited trifunctional properties of α-L-arabinofuranosidase, β-xylosidase, and endo-xylanase. Xyl43B6 showed broad specificity of substrates on aryl-arabinoside, aryl-xylopyranoside, xylooligosaccharides, xylobiose, low branching xylan, and highly substituted arabinoxylan. Xylose liberation rate from xylooligosaccharides was higher than from xylobiose. However, trace amount of xylose was detected from highly substistuted rye flour arabinoxylan, indicating influence of chain length and substitution groups on xylose liberation efficiency of Xyl43B6. Moreover, co-hydrolysis of Xyl43B6 with GH10 endo-xylanase (Xyn10E) on pretreated rice straw revealed the boosting effect and increase in liberated reducing sugar as a result of Xyl43B6/endo-xylanase synergy. This report proposed new ...

Chemical engineering transactions, 2020

Enzyme deactivation is a significant parameter to restrain the industrial commercialization of en... more Enzyme deactivation is a significant parameter to restrain the industrial commercialization of enzymes. In this study, a high-throughput screening technique using differential scanning fluorimetry (DSF) incorporated with enzyme activity analysis was thus developed in order to identify a suitable additive formulation for promoting enzyme stability in terms of conformational stability and functional activity. To demonstrate the concept feasibility, endo-xylanase obtained from metagenome of termite gut-inhabiting bacteria (XYN12) was used as a study model and several group of additives including salts, polymers, polyols and sugars at various concentrations and different combination patterns (single, double and triple pairing) were applied for investigating their effects on enzyme stability. As a result, a total of 80 reaction mixtures were retrieved including a native control (enzyme without any additives). DSF assay was performed using real-time PCR instrument to detect unfolding of p...

editor@tjprc.org SACCHARIFICATION OF ALKALINE TREATED RICE STRAW BY SUBSEQUENTLY HYDROLYSIS OF XY... more editor@tjprc.org SACCHARIFICATION OF ALKALINE TREATED RICE STRAW BY SUBSEQUENTLY HYDROLYSIS OF XYLANOLYTIC-CELLULOLYTIC ENZYMES FOR XYLOOLIGOSACCHARIDES AND GLUCOSE PRODUCTION KANOK WONGRATPANYA , JUNJARUS SERMSATHANASWADI , THIDARAT NIMCHUA , RATTIYA WAEONUKUL , PATTHRA PASON, CHAKRIT TACHAAPAIKOON , AKIHIKO KOSUGI 7 & KHANOK RATANAKHANOKCHAI 8 School of Bioresources and Technology, King Mongkut’ s University of Technology Thonburi, Bangkuntien Campus , Bangkok, Thailand Department of Chemical Technology, Faculty of Scienc e and Technology, Suan Dusit Rajabhat University, Bangkok, Thailand Enzyme Technology Laboratory, Bioresources Technolo gy Unit, National Center for Genetic Engineering and Biotechnology, Biotec, Thailand Science Park, Pathu mthani, Thailand Pilot Plant Development and Training Institute, Kin g Mongkut’s University of Technology Thonburi (Bangkuntien Campus), Bangkok, Thailand Biological Resources and Post-Harvest Division, Jap an International Research Center fo...

Cellulose nanofiber (CNF) was successfully isolated from kenaf bark by microfluidization at 20,00... more Cellulose nanofiber (CNF) was successfully isolated from kenaf bark by microfluidization at 20,000 psi for 40 passes. The combination of hydrothermal process and xylanase treatment prior to CNF isolation led to effective cellulose purification. The fiber used for enzymatic pretreatment for CNF isolation had an 85.9% whiteness index and 85.1% cellulose content. The crystallinity of the cellulose extracted from the kenaf bark continued to increase with successive treatments, as indicated by X-ray diffraction analysis. In addition, the enzyme-treated fiber showed increased thermal stability, as shown by thermogravimetric analysis. After CNF isolation, morphological characterization of the CNF was performed via field emission-scanning electron microscopy and transmission electron microscopy. The CNF had an average diameter that ranged from 5 to 10 nm and no undesired elemental contamination, as evidenced by energy dispersive X-ray spectroscopy. The mechano-enzymatic treatments used in t...

Indonesian Journal of Biotechnology, 2021

Thermoalkalophilic xylanases promise potential application in pulp biobleaching to reduce the use... more Thermoalkalophilic xylanases promise potential application in pulp biobleaching to reduce the use of toxic chlorinated chemical agents, which are harmful to the environment. In this study, a thermoalkalophilic endoxylanase gene (bhxyn3) originating from Indonesian indigenous Bacillus halodurans CM1 was cloned into yeast expression vector pPICZα A and expressed in Pichia pastoris KM71 under the control of AOX1 promoter. Recombinant P. pastoris expressed the highest final level of xylanase (146 U/mL) on BMGY medium after five days of cultivation. Optimization of xylanase production on a small scale was carried out by varying the methanol concentrations and the optimal xylanase production by the recombinant P. pastoris was observed in the culture with 2% (v/v) methanol after four days of the induction phase. The recombinant xylanase (BHxyn3E) was thermotolerant and alkalophilic, with an optimal temperature at around 55‐65 °C and under pH 8.0. The enzyme activity was slightly induced by...

Cellulose, 2020

This study investigated the effect of xylanase-assisted alkaline pretreatment (XAP) on the extrac... more This study investigated the effect of xylanase-assisted alkaline pretreatment (XAP) on the extraction of cellulose nanocrystal (CNCs) from energy cane (EC). Different concentrations of xylanase were tested to estimate the optimal enzyme loading required for pretreatment. XAP reduced the bleaching step from 7 to 5 h, generating a material with 93% whiteness index and a higher crystallinity index (CrI) than the alkaline-bleached fibers. A combined pretreatment using xylanase at 200 U/g removed 59 and 35% of hemicellulose and lignin, respectively, that was present in the EC which was confirmed using Fourier transform infrared spectroscopy and scanning electron microscopy analysis. X-ray diffraction and transmission electron microscopy revealed the XAP material required a shorter time of acid hydrolysis (30 min) to generate CNCs with similar lengths and CrI values to those obtained using only the alkaline pretreatment. Therefore, the XAP offered an efficient and promising approach for the isolation of CNCs with less use of chemicals for the bleaching process and a shorter hydrolysis time.

International Journal of Biological Macromolecules, 2019

Effect of xylanase-assisted pretreatment on the properties of cellulose and regenerated cellulose... more Effect of xylanase-assisted pretreatment on the properties of cellulose and regenerated cellulose films from sugarcane bagasse. Biomac (2018),

Journal of biotechnology, Jan 10, 2017

In the pulp bleaching industry, enzymes with robust activity at high pH and temperatures are desi... more In the pulp bleaching industry, enzymes with robust activity at high pH and temperatures are desirable for facilitating the pre-bleaching process with simplified processing and minimal use of chlorinated compounds. To engineer an enzyme for this purpose, we determined the crystal structure of the Xyn12.2 xylanase, a xylan-hydrolyzing enzyme derived from the termite gut symbiont metagenome, as the basis for structure-based protein engineering to improve Xyn12.2 stability in high heat and alkaline conditions. Engineered cysteine pairs that generated exterior disulfide bonds increased the kcat of Xyn12.2 variants and melting temperature at all tested conditions. These improvements led to up to 4.2-fold increases in catalytic efficiency at pH 9.0, 50°C for 1h and up to 3-fold increases at 60°C. The most effective variants, XynTT and XynTTTE, exhibited 2-3-fold increases in bagasse hydrolysis at pH 9.0 and 60°C compared to the wild-type enzyme. Overall, engineering arginines and phenylal...

BMC biotechnology, Jan 16, 2017

Removal of non-cellulosic impurities from cotton fabric, known as scouring, by conventional alkal... more Removal of non-cellulosic impurities from cotton fabric, known as scouring, by conventional alkaline treatment causes environmental problems and reduces physical strength of fabrics. In this study, an endo-polygalacturonase (EndoPG) from Aspergillus aculeatus produced in Pichia pastoris was evaluated for its efficiency as a bioscouring agent while most current bioscouring process has been performed using crude pectinase preparation. The recombinant EndoPG exhibited a specific activity of 1892.08 U/mg on citrus pectin under the optimal condition at 50 °C, pH 5.0 with a V max and K m of 65,451.35 μmol/min/mL and 15.14 mg/mL, respectively. A maximal activity of 2408.70 ± 26.50 U/mL in the culture supernatant was obtained by high cell density batch fermentation, equivalent to a 4.8 times greater yield than that from shake-flask culture. The recombinant enzyme was shown to be suitable for application as a bioscouring agent, in which the wettability of cotton fabric was increased by treat...

Industrial Crops and Products, 2017

Sugarcane bagasse has been utilized as a source of nanocellulose in nanomaterial science. However... more Sugarcane bagasse has been utilized as a source of nanocellulose in nanomaterial science. However, the biocompatibility of cellulose nanocrystals-based nanocomposites on human fibroblast skin cell has rarely been reported. Therefore, in this study, cellulose nanocrystals (CNCs) obtained from sugarcane bagasse were incorporated with polyvinyl alcohol (PVA) in the synthesis of tissue engineering scaffolds to reveal the responses of human skin cells to this scaffold in vitro. Scanning electron microscopy images illustrated that increasing the CNC concentration coincided with pore size enlargement to 164.7 m and 96.2 m for PVA/CNC nanocomposites and neat PVA, respectively. The three-dimensional porous structure of the nanocomposite showed irregular and interconnected pore structures as well as the pore distribution. Moreover, X-ray diffraction indicated that the relative crystallinity of the PVA with 2 and 4 wt% of CNCs was lower (44.94 ± 0.97% and 45.8 ± 1.05%, respectively) than that of neat PVA (49.79 ± 0.9%), and the highest relative crystallinity (48.53 ± 1.04%) was recorded at 6 wt% of CNCs. Fourier transform infrared spectroscopy was used to confirm the changes of chemical functional groups, and the non-cytotoxicity of PVA/CNC 10 was recorded at 82 ± 4.1% cell viability in an in vitro cytotoxicity test. Additionally, thermal, swelling and mechanical behaviors were significantly improved by increasing the CNC content. The compressive modulus and the major degradation temperature of PVA/CNC 10 reached 6.36 MPa and 343 ± 4.14 • C, respectively, while the swelling degree of 4 and 6 wt% CNCs scaffolds shared a similar maximum level of approximately 853%. Moreover, the biocompatibility of the obtained PVA/CNC 10 with a human fibroblast skin cell line (CRL-2522) illustrated good spreading and adhesion of cells on the material surfaces. These findings indicated that the integration of a PVA/CNC scaffold with fibroblast cells in vitro can be further studied for in vivo and biomedical applications.

Sugar Tech, 2017

Cellulose nanocrystals (CNCs) were extracted by sulfuric acid from cellulose purified via an envi... more Cellulose nanocrystals (CNCs) were extracted by sulfuric acid from cellulose purified via an environmentally friendly method. In this study, cellulose obtained from sugarcane bagasse (SCB) using steam-exploded and enzyme-treated pretreatment was confirmed using chemical composition analysis to have a 92.59 ± 0.12 whiteness index and 87% a-cellulose content. The morphology of extracted CNCs, characterized using atomic force microscopy images, transmission electron microscopy images and energy-dispersive x-rays, showed the diameter and length were in the ranges 9.8 ± 6.3 and 280.1 ± 73.3 nm, respectively, with an expected ratio (L/d) of 20-25 and a low concentration of sulfate (0.2%) on surface particles. Moreover, fourier transformed infrared spectroscopy and X-ray diffraction results demonstrated free noncellulosic contents and an improved crystallinity for CNCs, respectively. A decrease in the thermal stability of CNCs was examined by thermogravimetric analysis, and no evidence of cytotoxicity in the CNCs was obtained. The isolated CNCs from SCB may be considered as a potential biomedical material.

Industrial Crops and Products, 2016

Cellulose nanofibrils (CNFs) from sugarcane bagasse (SCB) were isolated by high-pressure homogeni... more Cellulose nanofibrils (CNFs) from sugarcane bagasse (SCB) were isolated by high-pressure homogenization. Xylanase-assisted pretreatment after steam explosion was studied to investigate its effect on various cellulose properties such as bleaching times, reduced chemical use and color in the subsequent bleaching stage. High cellulose contents were successfully extracted from SCB with xylanase-assisted pretreatment; moreover, xylanase-treated fibers exhibited decreased bleaching times, a 44% reduction in the amount of chemicals used and had a satisfactory whiteness index compared to untreated fibers. X-ray diffraction (XRD) analysis revealed significant increases in crystallinity index for xylanase-assisted pretreatment fibers. Characterization of the fibers by scanning electron microscopy (SEM) and atomic force microscopy (AFM) indicated that the fiber diameters decreased with each treatment stage; the final CNFs obtained at 15,000 psi for 30 passes primarily ranged from 5 to 10 nm in diameter. Thermogravimetric analysis (TGA) indicated that CNFs have lower thermal stability than raw cellulose fibers. These results indicate that xylanase-assisted pretreatment with high-pressure homogenization is an environmentally friendly method to isolate CNFs and clearly demonstrates the potential of enzymatic pretreatment for reducing environmental contamination, especially with regard to toxic chlorine compounds that are required for the bleaching process.

BioResources, 2015

The glycoside hydrolase family 43 from Paenibacillus curdlanolyticus strain B-6 (GH43B6) exhibite... more The glycoside hydrolase family 43 from Paenibacillus curdlanolyticus strain B-6 (GH43B6) exhibited multifunctional properties, including exo-βxylosidase, endo-xylanase, and α-L-arabinofuranosidase enzymatic activities. GH43B6 released xylose as a hydrolysis product from the successive reduction of xylooligosaccharides as a result of exo-βxylosidase activity. Moreover, GH43B6 also predominantly released xylose from low-substituted xylan derived from birchwood. However, when the highly substituted rye flour arabinoxylan was used as a substrate, exo-β-xylosidase activity changed to endo-xylanase activity, indicating that the enzymatic property of GH43B6 is influenced by the substituted side groups of xylan. For α-L-arabinofuranosidase, arabinose was released from short-chain substrates including p-nitrophenyl-α-Larabinofuranoside and α-L-Araf-(1→2)-[α-L-Araf-(1→3)]-β-D-Xylp. This study reports the novel trifunctional properties of GH43B6 containing exoand endo-activity together with xylanolytic debranching enzymatic activity, which increases its potential for application in lignocellulosebased biorefineries.

Microbial Ecology, 2010

A primary tropical peat swamp forest is a unique ecosystem characterized by long-term accumulatio... more A primary tropical peat swamp forest is a unique ecosystem characterized by long-term accumulation of plant biomass under high humidity and acidic waterlogged conditions, and is regarded as an important terrestrial carbon sink in the biosphere. In this study, the microbial community in the surface peat layer in Pru Toh Daeng, a primary tropical peat swamp forest, was studied for its phylogenetic diversity and metabolic potential using direct shotgun pyrosequencing of environmental DNA, together with analysis of 16S rRNA gene library and key metabolic genes. The community was dominated by aerobic microbes together with a significant number of facultative and anaerobic microbial taxa. Acidobacteria and diverse Proteobacteria (mainly Alphaproteobacteria) constituted the major phylogenetic groups, with minor representation of archaea and eukaryotic microbes. Based on comparative pyrosequencing dataset analysis, the microbial community showed high metabolic versatility of plant polysaccharide decomposition. A variety of glycosyl hydrolases targeting lignocellulosic and starch-based polysaccharides from diverse bacterial phyla were annotated, originating mostly from Proteobacteria, and Acidobacteria together with Firmicutes, Bacteroidetes, Chlamydiae/Verru-comicrobia, and Actinobacteria, suggesting the key role of these microbes in plant biomass degradation. Pyrosequencing dataset annotation and direct mcrA gene analysis indicated the presence of methanogenic archaea clustering in the order Methanomicrobiales, suggesting the potential on partial carbon flux from biomass degradation through methanogenesis. The insights on the peat swamp microbial assemblage thus provide a valuable approach for further study on biogeochemical processes in this unique ecosystem.

Journal of Microbiology and Biotechnology, 2012

Enzymatic pre-bleaching by modification of pulp fibers with xylanases is an attractive approach t... more Enzymatic pre-bleaching by modification of pulp fibers with xylanases is an attractive approach to reduce the consumption of toxic bleaching chemicals in the paper industry. In this study, an alkaliphilic endoxylanase gene was isolated from metagenomic DNA of a structurally stable thermophilic lignocellulose-degrading microbial consortium using amplification with conserved glycosyl hydrolase family 10 primers and subsequent genome walking. The full-length xylanase showed 78% sequence identity to an endo-β-1,4-xylanase of Clostridium phytofermentans and was expressed in a mature form with an N-terminal His 6 tag fusion in Escherichia coli. The recombinant xylanase Xyn3F was thermotolerant and alkaliphilic, working optimally at 65-70 o C with an optimal pH at 9-10 and retaining >80% activity at pH 9, 60 o C for 1 h. Xyn3F showed a V max of 2,327 IU/mg and K m of 3.5 mg/ml on birchwood xylan. Pre-bleaching of industrial eucalyptus pulp with no prior pH adjustment (pH 9) using Xyn3F at 50 IU/g dried pulp led to 4.5-5.1% increase in final pulp brightness and 90.4-102.4% increase in whiteness after a single-step hypochlorite bleaching over the untreated pulp, which allowed at least 20% decrease in hypochlorite consumption to achieve the same final bleaching indices. The alkaliphilic xylanase is promising for application in an environmentally friendly bleaching step of kraft and soda pulps with no requirement for pH adjustment, leading to improved economic feasibility of the process.