• 제목/요약/키워드: lignocellulose

검색결과 95건 처리시간 0.022초

Comparative Enzyme Production by Fungi from Diverse Lignocellulosic Substrates

  • Sin, Marie K.W.;Hyde, Kevin D.;Pointing, Stephen B.
    • Journal of Microbiology
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    • 제40권3호
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    • pp.241-244
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    • 2002
  • Fungi commonly encountered on monocotyledonous substrates were evaluated for their in vitro ability to produce enzymes involved in lignocellulose breakdown. Most were capable of structural polysac-charide utilization, but few produced enzymes associated with lignin breakdown. None of the mono-cotyledon-inhabiting fungi produced reactions as strongly as wood decay fungi.

L-Glycine Alleviates Furfural-Induced Growth Inhibition during Isobutanol Production in Escherichia coli

  • Song, Hun-Suk;Jeon, Jong-Min;Choi, Yong Keun;Kim, Jun-Young;Kim, Wooseong;Yoon, Jeong-Jun;Park, Kyungmoon;Ahn, Jungoh;Lee, Hongweon;Yang, Yung-Hun
    • Journal of Microbiology and Biotechnology
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    • 제27권12호
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    • pp.2165-2172
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    • 2017
  • Lignocellulose is now a promising raw material for biofuel production. However, the lignin complex and crystalline cellulose require pretreatment steps for breakdown of the crystalline structure of cellulose for the generation of fermentable sugars. Moreover, several fermentation inhibitors are generated with sugar compounds, majorly furfural. The mitigation of these inhibitors is required for the further fermentation steps to proceed. Amino acids were investigated on furfural-induced growth inhibition in E. coli producing isobutanol. Glycine and serine were the most effective compounds against furfural. In minimal media, glycine conferred tolerance against furfural. From the $IC_{50}$ value for inhibitors in the production media, only glycine could alleviate growth arrest for furfural, where 6 mM glycine addition led to a slight increase in growth rate and isobutanol production from 2.6 to 2.8 g/l under furfural stress. Overexpression of glycine pathway genes did not lead to alleviation. However, addition of glycine to engineered strains blocked the growth arrest and increased the isobutanol production about 2.3-fold.

Rewiring carbon catabolite repression for microbial cell factory

  • Vinuselvi, Parisutham;Kim, Min-Kyung;Lee, Sung-Kuk;Ghim, Cheol-Min
    • BMB Reports
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    • 제45권2호
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    • pp.59-70
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    • 2012
  • Carbon catabolite repression (CCR) is a key regulatory system found in most microorganisms that ensures preferential utilization of energy-efficient carbon sources. CCR helps microorganisms obtain a proper balance between their metabolic capacity and the maximum sugar uptake capability. It also constrains the deregulated utilization of a preferred cognate substrate, enabling microorganisms to survive and dominate in natural environments. On the other side of the same coin lies the tenacious bottleneck in microbial production of bioproducts that employs a combination of carbon sources in varied proportion, such as lignocellulose-derived sugar mixtures. Preferential sugar uptake combined with the transcriptional and/or enzymatic exclusion of less preferred sugars turns out one of the major barriers in increasing the yield and productivity of fermentation process. Accumulation of the unused substrate also complicates the downstream processes used to extract the desired product. To overcome this difficulty and to develop tailor-made strains for specific metabolic engineering goals, quantitative and systemic understanding of the molecular interaction map behind CCR is a prerequisite. Here we comparatively review the universal and strain-specific features of CCR circuitry and discuss the recent efforts in developing synthetic cell factories devoid of CCR particularly for lignocellulose-based biorefinery.

Saccharomyces cerevisiae Strain Improvement Using Selection, Mutation, and Adaptation for the Resistance to Lignocellulose-Derived Fermentation Inhibitor for Ethanol Production

  • Jang, Youri;Lim, Younghoon;Kim, Keun
    • Journal of Microbiology and Biotechnology
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    • 제24권5호
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    • pp.667-674
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    • 2014
  • Twenty-five Saccharomyces cerevisiae strains were screened for the highest sugar tolerance, ethanol-tolerance, ethanol production, and inhibitor resistance, and S. cerevisiae KL5 was selected as the best strain. Inhibitor cocktail (100%) was composed of 75 mM formic acid, 75 mM acetic acid, 30 mM furfural, 30 mM hydroxymethyl furfural (HMF), and 2.7 mM vanillin. The cells of strain KL5 were treated with ${\gamma}$-irradiation, and among the survivals, KL5-G2 with improved inhibitor resistance and the highest ethanol yield in the presence of inhibitor cocktail was selected. The KL5-G2 strain was adapted to inhibitor cocktail by sequential transfer of cultures to a minimal YNB medium containing increasing concentrations of inhibitor cocktail. After 10 times of adaptation, most of the isolated colonies could grow in YNB with 80% inhibitor cocktail, whereas the parental KL5 strain could not grow at all. Among the various adapted strains, the best strain (KL5-G2-A9) producing the highest ethanol yield in the presence of inhibitor cocktail was selected. In a complex YP medium containing 60% inhibitor cocktail and 5% glucose, the theoretical yield and productivity (at 48 h) of KL5-G2-A9 were 81.3% and 0.304 g/l/h, respectively, whereas those of KL5 were 20.8% and 0.072 g/l/h, respectively. KL5-G2-A9 reduced the concentrations of HMF, furfural, and vanillin in the medium in much faster rates than KL5.

Functional Characteristics and Diversity of a Novel Lignocelluloses Degrading Composite Microbial System with High Xylanase Activity

  • Guo, Peng;Zhu, Wanbin;Wang, Hui;Lu, Yucai;Wang, Xiaofen;Zheng, Dan;Cui, Zongjun
    • Journal of Microbiology and Biotechnology
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    • 제20권2호
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    • pp.254-264
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    • 2010
  • To obtain an efficient natural lignocellulolytic complex enzyme, we screened an efficient lignocellulose-degrading composite microbial system (XDC-2) from composted agricultural and animal wastes amended soil following a long-term directed acclimation. Not only could the XDC-2 degrade natural lignocelluloses, but it could also secrete extracellular xylanase efficiently in liquid culture under static conditions at room temperature. The XDC-2 degraded rice straw by 60.3% after fermentation for 15 days. Hemicelluloses were decomposed effectively, whereas the extracellular xylanase activity was dominant with an activity of 8.357 U/ml on day 6 of the fermentation period. The extracellular crude enzyme noticeably hydrolyzed natural lignocelluloses. The optimum temperature and pH for the xylanase activity were $40^{\circ}C$ and 6.0. However, the xylanase was activated in a wide pH range of 3.0-10.0, and retained more than 80% of its activity at $25-35^{\circ}C$ and pH 5.0-8.0 after three days of incubation in liquid culture under static conditions. PCR-DGGE analysis of successive subcultures indicated that the XDC-2 was structurally stable over long-term restricted and directed cultivation. Analysis of the 168 rRNA gene clone library showed that the XDC-2 was mainly composed of mesophilic bacteria related to the genera Clostridium, Bacteroides, Alcaligenes, Pseudomonas, etc. Our results offer a new approach to exploring efficient lignocellulolytic enzymes by constructing a high-performance composite microbial system with synergistic complex enzymes.

Metagenomic Analysis of Novel Lignocellulose-Degrading Enzymes from Higher Termite Guts Inhabiting Microbes

  • Nimchua, Thidarat;Thongaram, Taksawan;Uengwetwanit, Tanaporn;Pongpattanakitshote, Somchai;Eurwilaichitr, Lily
    • Journal of Microbiology and Biotechnology
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    • 제22권4호
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    • pp.462-469
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    • 2012
  • A metagenomic fosmid library was constructed from genomic DNA isolated from the microbial community residing in hindguts of a wood-feeding higher termite (Microcerotermes sp.) collected in Thailand. The library was screened for clones expressing lignocellulolytic activities. Fourteen independent active clones (2 cellulases and 12 xylanases) were obtained by functional screening at pH 10.0. Analysis of shotgun-cloning and pyrosequencing data revealed six ORFs, which shared less than 59% identity and 73% similarity of their amino acid sequences with known cellulases and xylanases. Conserved domain analysis of these ORFs revealed a cellulase belonging to the glycoside hydrolase family 5, whereas the other five xylanases showed significant identity to diverse families including families 8, 10, and 11. Interestingly, one fosmid clone was isolated carrying three contiguous xylanase genes that may comprise a xylanosome operon. The enzymes with the highest activities at alkaline pH from the initial activity screening were characterized biochemically. These enzymes showed a broad range of enzyme activities from pH 5.0 to 10.0, with pH optimal of 8.0 retaining more than 70% of their respective activities at pH 9.0. The optimal temperatures of these enzymes ranged from $50^{\circ}C$ to $55^{\circ}C$. This study provides evidence for the diversity and function of lignocellulose-degrading enzymes in the termite gut microbial community, which could be of potential use for industrial processes such as pulp biobleaching and denim biostoning.

개질처리된 목질계 스페이서의 산업용지 생산현장 적용평가 (The Evaluation of the Application of Modified Wood Powder Spacers to Liner Board Mill Trials)

  • 서영범;윤도현;성용주;권완오;김진두
    • 펄프종이기술
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    • 제47권5호
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    • pp.98-103
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    • 2015
  • The reduction of the energy consumption in papermaking process become more important issue because of the regulation of green house gas (GHG) emission. Since more than half of energy for papermaking process is consumed during drying process, the increase of the drying efficiency would be very important solution for saving energy and reduction of GHG emission. The improvement of drying efficiency could be very difficult for the liner board mill because the liner board are usually made of recycled paper, OCC (old corrugated container). The short fiber and fines originated the OCC lead to compact sheet structure and delay the water flow out during wet pressing process and drying process. The application of lignocellulose spacer could provide more loose wet sheet structure and result in the higher drainage rate and the improved drying efficiency. In this study, the effects of the application of lignocellulose spacer to the liner board mill were evaluated based on the mill trial. In order to overcome the common disadvantage of the spacer, the loss of strength properties, the spacer was pretreated with amphoteric polyelectrolyte during mill trial. The results showed the application of pretreated spacer improved the drying efficiency by reducing steam consumption. And the loss in the strength properties by the spacer could be supplemented by the pretreatment.

The Physical, Mechanical, and Sound Absorption Properties of Sandwich Particleboard (SPb)

  • ISWANTO, Apri Heri;HAKIM, Arif Rahman;AZHAR, Irawati;WIRJOSENTONO, Basuki;PRABUNINGRUM, Dita Sari
    • Journal of the Korean Wood Science and Technology
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    • 제48권1호
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    • pp.32-40
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    • 2020
  • While the utilization of wood as a raw material in related industries has been increasing with the population increasing, the availability of wood from natural forests has continued to decline. An alternative to this situation is the manufacture of particleboard from non-wood lignocellulose materials through the modification of sandwich particleboard (SPb) using bamboo strands as reinforcement. In this study, strandsof belangke bamboo (Gigantochloa pruriens W) and tali bamboo (Gigantochloa apus) were utilized. The non-wood particles included sugar palm fibers, cornstalk, and sugarcane bagasse. The board was made in a three-layer composition of the face, back, and core in a ratio of 1: 2: 1. The binder used was 8% isocyanate resin. The sheet was pressed at a temperature of 160℃ for 5 min under a pressure of 3.0 N/㎟. Testing included physical and mechanical properties based on the JIS A 5908 (2003) standard, while acoustic testing was based on ISO 11654 (1997) standards. The results showed that using bamboo strands as reinforcement has an effect on the mechanical and physical properties of SPb. Almost all the types of boards met the JIS A 5908 (2003) standards, with the exception of thickness swelling (TS) and internal bond (IB) parameters. Based on the thickness swelling parameter, the C-type board exhibited the best properties. Overall, the B-type board thatused a belangke bamboo strand for the surface and sugarcane bagasse as the core underwent the best treatment. Based on the acoustical parameter, boards using a tali bamboo strand for the surface and sugar palm fiber as the core (E-type board) exhibited good sound absorption properties.

Bioconversion of Lignocellulosic Materials with the Contribution of a Multifunctional GH78 Glycoside Hydrolase from Xylaria polymorpha to Release Aromatic Fragments and Carbohydrates

  • Liers, Christiane;Ullrich, Rene;Kellner, Harald;Chi, Do Huu;Quynh, Dang Thu;Luyen, Nguyen Dinh;Huong, Le Mai;Hofrichter, Martin;Nghi, Do Huu
    • Journal of Microbiology and Biotechnology
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    • 제31권10호
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    • pp.1438-1445
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    • 2021
  • A bifunctional glycoside hydrolase GH78 from the ascomycete Xylaria polymorpha (XpoGH78) possesses catalytic versatility towards both glycosides and esters, which may be advantageous for the efficient degradation of the plant cell-wall complex that contains both diverse sugar residues and esterified structures. The contribution of XpoGH78 to the conversion of lignocellulosic materials without any chemical pretreatment to release the water-soluble aromatic fragments, carbohydrates, and methanol was studied. The disintegrating effect of enzymatic lignocellulose treatment can be significantly improved by using different kinds of hydrolases and phenoloxidases. The considerable changes in low (3 kDa), medium (30 kDa), and high (> 200 kDa) aromatic fragments were observed after the treatment with XpoGH78 alone or with this potent cocktail. Synergistic conversion of rape straw also resulted in a release of 17.3 mg of total carbohydrates (e.g., arabinose, galactose, glucose, mannose, xylose) per gram of substrate after incubating for 72 h. Moreover, the treatment of rape straw with XpoGH78 led to a marginal methanol release of approximately 17 ㎍/g and improved to 270 ㎍/g by cooperation with the above accessory enzymes. In the case of beech wood conversion, the combined catalysis by XpoGH78 and laccase caused an effect comparable with that of fungal strain X. polymorpha in woody cultures concerning the liberation of aromatic lignocellulose fragments.

원목재배용 표고(Lentinula edodes)의 목질섬유소 분해특성 비교 (Analysis of lignocellulose degradation by Oak mushroom (Lentinula edodes))

  • 정상욱;장은경;정찬문;고한규;권혁우;반승언
    • 한국버섯학회지
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    • 제16권4호
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    • pp.272-278
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    • 2018
  • 본 연구에서는 원목재배용 표고(Lentinula edodes) 품종에 대한 목질섬유소 분해능을 검정하였다. 5개의 국산품종(천백고, 산조 303호, 풍년고, 백화향, 수향고)을 대상으로 malt extract broth(MEB) 배지에 lignin의 첨가에 따른 RBBR(Remazol Brilliant Blue R) 탈색능을 조사한 결과, 산조 303호와 풍년고가 배양 5일째부터 우수한 분해능을 보였다. 섬유소 분해효소인 MnP와 laccase의 활성은 풍년고가 배양 7일째 MnP 활성이 2,809U/mg, laccase 활성이 2,230U/mg으로 나타났고, 산조 303호가 배양 11일째 MnP 활성이 2,673U/mg, laccase 활성이 2,049U/mg으로 최고 활성을 나타났으며, lignin을 첨가하였을 때 효소의 활성이 증가하였다. 산조 303호, 풍년고와 수향고는 배양 5주 만에 filter paper의 분해정도를 육안으로 확인이 가능할 정도로 분해능이 우수하였다.