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Joglekar AV, Karanth NG. Studies on cellulase production by a mutant-penicillium funiculosum uv-49. Biotechnol Bioeng 2012; 26:1079-84. [PMID: 18553529 DOI: 10.1002/bit.260260910] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In search of hypercellulolytic microorganisms, ultraviolet irradiation carried out with Penicillium funiculosum has yielded a superior mutant. The investigations reported in this article are shake flask studies on some important nutritional requirements of the mutant, namely, nitrogen source, carbon source, and inducers. The mutant shows an ability to metabolize inorganic nitrogen sources like urea and sodium nitrate both for growth and enzyme production. A comparison of the long-term saccharification ability and the utilization efficiency of the mutant enzyme with those reported in the literature is also carried out, showing the superior performance of the mutant enzyme.
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Affiliation(s)
- A V Joglekar
- Biochemical Engineering Group, Chemical Engineering Division, National Chemical Laboratory, Pune 411 008, India
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52
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Zhong Y, Wang X, Yu H, Liang S, Wang T. Application of T-DNA insertional mutagenesis for improving cellulase production in the filamentous fungus Trichoderma reesei. BIORESOURCE TECHNOLOGY 2012; 110:572-7. [PMID: 22365717 DOI: 10.1016/j.biortech.2012.01.129] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 01/21/2012] [Accepted: 01/23/2012] [Indexed: 05/07/2023]
Abstract
A T-DNA-tagged mutant library created by Agrobacterium-mediated transformation (AMT) was assayed for improvement of cellulase production. After 96-well plate screening for rapid growth on cellulose substrates followed by plate-clearing zone assay, three putative mutants, TA-32, TB-87 and TE-6, with enhanced cellulolytic ability were isolated, exhibiting 38%, 51% and 31% increase in total cellulase activity than the parental strain QM9414, respectively. Endoglucanase, cellobiohydrolase and β-glucosidase activities as well as the hydrolysis efficiencies of the mutants were also improved. Moreover, T-DNA was shown to be integrated at a single site in the genomes of TA-32 and TE-6 while inserted at two copies into the genome of TB-87. Further, the sequences flanking the T-DNA insertion sites were successfully rescued, demonstrating the increased utility of T-DNA insertional mutagenesis for improvement of cellulase production as well as subsequent identification of the tagged genes relevant to cellulolytic ability.
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Affiliation(s)
- Yaohua Zhong
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27, Shanda South Road, Jinan 250100, PR China
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53
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Schuster A, Bruno KS, Collett JR, Baker SE, Seiboth B, Kubicek CP, Schmoll M. A versatile toolkit for high throughput functional genomics with Trichoderma reesei. BIOTECHNOLOGY FOR BIOFUELS 2012; 5:1. [PMID: 22448811 PMCID: PMC3260098 DOI: 10.1186/1754-6834-5-1] [Citation(s) in RCA: 170] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 01/02/2012] [Indexed: 05/03/2023]
Abstract
BACKGROUND The ascomycete fungus, Trichoderma reesei (anamorph of Hypocrea jecorina), represents a biotechnological workhorse and is currently one of the most proficient cellulase producers. While strain improvement was traditionally accomplished by random mutagenesis, a detailed understanding of cellulase regulation can only be gained using recombinant technologies. RESULTS Aiming at high efficiency and high throughput methods, we present here a construction kit for gene knock out in T. reesei. We provide a primer database for gene deletion using the pyr4, amdS and hph selection markers. For high throughput generation of gene knock outs, we constructed vectors using yeast mediated recombination and then transformed a T. reesei strain deficient in non-homologous end joining (NHEJ) by spore electroporation. This NHEJ-defect was subsequently removed by crossing of mutants with a sexually competent strain derived from the parental strain, QM9414. CONCLUSIONS Using this strategy and the materials provided, high throughput gene deletion in T. reesei becomes feasible. Moreover, with the application of sexual development, the NHEJ-defect can be removed efficiently and without the need for additional selection markers. The same advantages apply for the construction of multiple mutants by crossing of strains with different gene deletions, which is now possible with considerably less hands-on time and minimal screening effort compared to a transformation approach. Consequently this toolkit can considerably boost research towards efficient exploitation of the resources of T. reesei for cellulase expression and hence second generation biofuel production.
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Affiliation(s)
- André Schuster
- Chemical and Biological Process Development, Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, USA
- Research Area of Gene Technology and Applied Biochemistry, Institute for Chemical Engineering, Vienna University of Technology, Gumpendorfer Strasse 1a/1665, A-1060 Wien, Austria
| | - Kenneth S Bruno
- Chemical and Biological Process Development, Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, USA
| | - James R Collett
- Chemical and Biological Process Development, Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, USA
| | - Scott E Baker
- Chemical and Biological Process Development, Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, USA
| | - Bernhard Seiboth
- Research Area of Gene Technology and Applied Biochemistry, Institute for Chemical Engineering, Vienna University of Technology, Gumpendorfer Strasse 1a/1665, A-1060 Wien, Austria
| | - Christian P Kubicek
- Research Area of Gene Technology and Applied Biochemistry, Institute for Chemical Engineering, Vienna University of Technology, Gumpendorfer Strasse 1a/1665, A-1060 Wien, Austria
| | - Monika Schmoll
- Research Area of Gene Technology and Applied Biochemistry, Institute for Chemical Engineering, Vienna University of Technology, Gumpendorfer Strasse 1a/1665, A-1060 Wien, Austria
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Albaek MO, Gernaey KV, Hansen MS, Stocks SM. Evaluation of the energy efficiency of enzyme fermentation by mechanistic modeling. Biotechnol Bioeng 2011; 109:950-61. [DOI: 10.1002/bit.24364] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 09/12/2011] [Accepted: 10/25/2011] [Indexed: 11/10/2022]
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Peterson R, Nevalainen H. Trichoderma reesei RUT-C30--thirty years of strain improvement. MICROBIOLOGY-SGM 2011; 158:58-68. [PMID: 21998163 DOI: 10.1099/mic.0.054031-0] [Citation(s) in RCA: 292] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The hypersecreting mutant Trichoderma reesei RUT-C30 (ATCC 56765) is one of the most widely used strains of filamentous fungi for the production of cellulolytic enzymes and recombinant proteins, and for academic research. The strain was obtained after three rounds of random mutagenesis of the wild-type QM6a in a screening program focused on high cellulase production and catabolite derepression. Whereas RUT-C30 achieves outstanding levels of protein secretion and high cellulolytic activity in comparison to the wild-type QM6a, recombinant protein production has been less successful. Here, we bring together and discuss the results from biochemical-, microscopic-, genomic-, transcriptomic-, glycomic- and proteomic-based research on the RUT-C30 strain published over the last 30 years.
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Affiliation(s)
- Robyn Peterson
- Biomolecular Frontiers Research Centre, Macquarie University, Australia
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Australia
| | - Helena Nevalainen
- Biomolecular Frontiers Research Centre, Macquarie University, Australia
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Australia
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56
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Improvement of cellulase activity in Trichoderma reesei by heterologous expression of a beta-glucosidase gene from Penicillium decumbens. Enzyme Microb Technol 2011; 49:366-71. [DOI: 10.1016/j.enzmictec.2011.06.013] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 06/11/2011] [Accepted: 06/18/2011] [Indexed: 11/23/2022]
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Limón MC, Pakula T, Saloheimo M, Penttilä M. The effects of disruption of phosphoglucose isomerase gene on carbon utilisation and cellulase production in Trichoderma reesei Rut-C30. Microb Cell Fact 2011; 10:40. [PMID: 21609467 PMCID: PMC3126698 DOI: 10.1186/1475-2859-10-40] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 05/24/2011] [Indexed: 01/31/2023] Open
Abstract
Background Cellulase and hemicellulase genes in the fungus Trichoderma reesei are repressed by glucose and induced by lactose. Regulation of the cellulase genes is mediated by the repressor CRE1 and the activator XYR1. T. reesei strain Rut-C30 is a hypercellulolytic mutant, obtained from the natural strain QM6a, that has a truncated version of the catabolite repressor gene, cre1. It has been previously shown that bacterial mutants lacking phosphoglucose isomerase (PGI) produce more nucleotide precursors and amino acids. PGI catalyzes the second step of glycolysis, the formation of fructose-6-P from glucose-6-P. Results We deleted the gene pgi1, encoding PGI, in the T. reesei strain Rut-C30 and we introduced the cre1 gene in a Δpgi1 mutant. Both Δpgi1 and cre1+Δpgi1 mutants showed a pellet-like and growth as well as morphological alterations compared with Rut-C30. None of the mutants grew in media with fructose, galactose, xylose, glycerol or lactose but they grew in media with glucose, with fructose and glucose, with galactose and fructose or with lactose and fructose. No growth was observed in media with xylose and glucose. On glucose, Δpgi1 and cre1+Δpgi1 mutants showed higher cellulase activity than Rut-C30 and QM6a, respectively. But in media with lactose, none of the mutants improved the production of the reference strains. The increase in the activity did not correlate with the expression of mRNA of the xylanase regulator gene, xyr1. Δpgi1 mutants were also affected in the extracellular β-galactosidase activity. Levels of mRNA of the glucose 6-phosphate dehydrogenase did not increase in Δpgi1 during growth on glucose. Conclusions The ability to grow in media with glucose as the sole carbon source indicated that Trichoderma Δpgi1 mutants were able to use the pentose phosphate pathway. But, they did not increase the expression of gpdh. Morphological characteristics were the result of the pgi1 deletion. Deletion of pgi1 in Rut-C30 increased cellulase production, but only under repressing conditions. This increase resulted partly from the deletion itself and partly from a genetic interaction with the cre1-1 mutation. The lower cellulase activity of these mutants in media with lactose could be attributed to a reduced ability to hydrolyse this sugar but not to an effect on the expression of xyr1.
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Affiliation(s)
- M Carmen Limón
- VTT, P,O, Box 1000, (Tietotie 2, Espoo), FIN-02044 VTT, Finland.
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58
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Differential regulation of the cellulase transcription factors XYR1, ACE2, and ACE1 in Trichoderma reesei strains producing high and low levels of cellulase. EUKARYOTIC CELL 2010; 10:262-71. [PMID: 21169417 DOI: 10.1128/ec.00208-10] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Due to its capacity to produce large amounts of cellulases, Trichoderma reesei is increasingly being investigated for second-generation biofuel production from lignocellulosic biomass. The induction mechanisms of T. reesei cellulases have been described recently, but the regulation of the genes involved in their transcription has not been studied thoroughly. Here we report the regulation of expression of the two activator genes xyr1 and ace2, and the corepressor gene ace1, during the induction of cellulase biosynthesis by the inducer lactose in T. reesei QM 9414, a strain producing low levels of cellulase (low producer). We show that all three genes are induced by lactose. xyr1 was also induced by d-galactose, but this induction was independent of d-galactose metabolism. Moreover, ace1 was carbon catabolite repressed, whereas full induction of xyr1 and ace2 in fact required CRE1. Significant differences in these regulatory patterns were observed in the high-producer strain RUT C30 and the hyperproducer strain T. reesei CL847. These observations suggest that a strongly elevated basal transcription level of xyr1 and reduced upregulation of ace1 by lactose may have been important for generating the hyperproducer strain and that thus, these genes are major control elements of cellulase production.
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59
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Throndset W, Bower B, Caguiat R, Baldwin T, Ward M. Isolation of a strain of Trichoderma reesei with improved glucoamylase secretion by flow cytometric sorting. Enzyme Microb Technol 2010. [DOI: 10.1016/j.enzmictec.2010.09.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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60
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de Castro AM, Ferreira MC, da Cruz JC, Pedro KCNR, Carvalho DF, Leite SGF, Pereira N. High-Yield Endoglucanase Production by Trichoderma harzianum IOC-3844 Cultivated in Pretreated Sugarcane Mill Byproduct. Enzyme Res 2010; 2010:854526. [PMID: 21048871 PMCID: PMC2962913 DOI: 10.4061/2010/854526] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 07/15/2010] [Accepted: 08/12/2010] [Indexed: 11/20/2022] Open
Abstract
The low-cost production of cellulolytic complexes presenting high action at mild conditions and well-balanced cellulase activities is one of the major bottlenecks for the economical viability of the production of cellulosic ethanol. In the present paper, the filamentous fungus Trichoderma harzianum IOC-3844 was used for the production of cellulases from a pretreated sugarcane bagasse (namely, cellulignin), by submerged fermentation. This fungal strain produced high contents of endoglucanase activity (6,358 U·L(-1)) after 72 hours of process, and further relevant β-glucosidase and FPase activities (742 and 445 U·L(-1), resp.). The crude enzyme extract demonstrated appropriate characteristics for its application in cellulose hydrolysis, such as high thermal stability at up to 50°C, accessory xylanase activity, and absence of proteolytic activity towards azocasein. This strain showed, therefore, potential for the production of complete cellulolytic complexes aiming at the saccharification of lignocellulosic materials.
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Affiliation(s)
- Aline Machado de Castro
- Renewable Energy Division, Research and Development Center, Petrobras, Avenue Horácio Macedo, 950 Ilha do Fundão, 21941-915 Rio de Janeiro, RJ, Brazil
| | - Marcela Costa Ferreira
- School of Chemistry, Federal University of Rio de Janeiro, 21945-970 Rio de Janeiro, RJ, Brazil
| | - Juliana Cunha da Cruz
- School of Chemistry, Federal University of Rio de Janeiro, 21945-970 Rio de Janeiro, RJ, Brazil
| | | | | | | | - Nei Pereira
- School of Chemistry, Federal University of Rio de Janeiro, 21945-970 Rio de Janeiro, RJ, Brazil
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61
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Vitikainen M, Arvas M, Pakula T, Oja M, Penttilä M, Saloheimo M. Array comparative genomic hybridization analysis of Trichoderma reesei strains with enhanced cellulase production properties. BMC Genomics 2010; 11:441. [PMID: 20642838 PMCID: PMC3091638 DOI: 10.1186/1471-2164-11-441] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Accepted: 07/19/2010] [Indexed: 11/10/2022] Open
Abstract
Background Trichoderma reesei is the main industrial producer of cellulases and hemicellulases that are used to depolymerize biomass in a variety of biotechnical applications. Many of the production strains currently in use have been generated by classical mutagenesis. In this study we characterized genomic alterations in high-producing mutants of T. reesei by high-resolution array comparative genomic hybridization (aCGH). Our aim was to obtain genome-wide information which could be utilized for better understanding of the mechanisms underlying efficient cellulase production, and would enable targeted genetic engineering for improved production of proteins in general. Results We carried out an aCGH analysis of four high-producing strains (QM9123, QM9414, NG14 and Rut-C30) using the natural isolate QM6a as a reference. In QM9123 and QM9414 we detected a total of 44 previously undocumented mutation sites including deletions, chromosomal translocation breakpoints and single nucleotide mutations. In NG14 and Rut-C30 we detected 126 mutations of which 17 were new mutations not documented previously. Among these new mutations are the first chromosomal translocation breakpoints identified in NG14 and Rut-C30. We studied the effects of two deletions identified in Rut-C30 (a deletion of 85 kb in the scaffold 15 and a deletion in a gene encoding a transcription factor) on cellulase production by constructing knock-out strains in the QM6a background. Neither the 85 kb deletion nor the deletion of the transcription factor affected cellulase production. Conclusions aCGH analysis identified dozens of mutations in each strain analyzed. The resolution was at the level of single nucleotide mutation. High-density aCGH is a powerful tool for genome-wide analysis of organisms with small genomes e.g. fungi, especially in studies where a large set of interesting strains is analyzed.
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Affiliation(s)
- Marika Vitikainen
- VTT Technical Research Centre of Finland, FI-02044 VTT, Espoo, Finland.
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62
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Abstract
Both photosynthetic and nonphotosynthetic microorganisms, grown on various carbon and energy sources, are used in fermentation processes for the production of single-cell proteins. Commercial-scale production has been limited to two algal processes, one bacterial process, and several yeast and fungal processes. High capital and operating costs and the need for extensive nutritional and toxicological assessments have limited the development and commercialization of new processes. Any increase in commercial-scale production appears to be limited to those regions of the world where low-cost carbon and energy sources are available and conventional animal feedstuff proteins, such as soybean meal or fish meal, are in short supply.
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63
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Saddler JN, Yu EK, Mes-Hartree M, Levitin N, Brownell HH. Utilization of enzymatically hydrolyzed wood hemicelluloses by microorganisms for production of liquid fuels. Appl Environ Microbiol 2010; 45:153-60. [PMID: 16346161 PMCID: PMC242246 DOI: 10.1128/aem.45.1.153-160.1983] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hemicellulose-derived sugars were obtained from a variety of pretreated wood substrates such as water-soluble fractions from steam-exploded aspen, solvent-extracted aspen, and commercial xylan. These fractions were enzymatically hydrolyzed by commercial enzyme preparations and by the culture filtrates of eight highly cellulolytic fungi. The sugars released were assayed by high-pressure liquid chromatography. Over 30% of the hemicellulose fractions, at a 10% substrate concentration, could be hydrolyzed to monosaccharides. These hemicellulose hydrolysates were used as the substrates for growth of Clostridium acetobutylicum and Klebsiella pneumoniae. Comparatively low butanol values were obtained with C. acetobutylicum, although over 50% of the hemicellulose fraction, at a 1% substrate concentration, could be converted to 2,3-butanediol, ethanol, and acetic acid by K. pneumoniae.
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Affiliation(s)
- J N Saddler
- Biotechnology and Chemistry Groups, Eastern Laboratory, Forintek Canada Corp., Ottawa, Ontario, Canada K1G 3Z5
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64
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Rubini M, Dillon A, Kyaw C, Faria F, Poças-Fonseca M, Silva-Pereira I. Cloning, characterization and heterologous expression of the firstPenicillium echinulatumcellulase gene. J Appl Microbiol 2010; 108:1187-98. [DOI: 10.1111/j.1365-2672.2009.04528.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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65
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Moloney AP, Considine PJ, Coughlan MP. Cellulose hydrolysis by the cellulases produced by Talaromyces emersonii when grown on different inducing substrates. Biotechnol Bioeng 2009; 25:1169-73. [PMID: 18548728 DOI: 10.1002/bit.260250423] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- A P Moloney
- Department of Biochemistry, University College, Galway, Ireland
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66
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Schafner DW, Toledo RT. Cellulase production in continuous culture by Trichoderma reesei on xylose-based media. Biotechnol Bioeng 2009; 39:865-9. [PMID: 18601020 DOI: 10.1002/bit.260390808] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Trichoderma reesei (QM 9414) produced cellulase in continuous culture, on media containing xylose (1%) supplemented with sorbose (0.3%) to induce cellulase production. Maximum cell mass of 4.54 kg/m(3) occurred at pH 4.0 and a dilution rate of 0.0391 h(-1) where residual substrate was 0.43 kg/m(3), but no cellulase was produced. Maximum cellulase production of 0.69 FPU occurred at pH 3.5 and a dilution rate of 0.0110 h(-1), where cell mass production was 2.56 kg/m(3) and residual substrate was 0.15 kg/m(3). Monod kinetic constants, corrected for endogenous metabolism, were 0.091 h(-1), 0.469 kg/m(3), 0.00923 h(-1), and 0.470 kg cells/kg xylose at pH 3.5, for the maximum specific growth rate, Michaelis-Menten coefficient, endogenous metabolism coefficient, and yield coefficient, respectively. Specific growth rate fitted a maturation time model, which predicted decreasing maturation time with increasing pH.
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Affiliation(s)
- D W Schafner
- Department of Food Science and Technology, University of Georgia, Athens, GA 30602, USA
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67
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Dashtban M, Schraft H, Qin W. Fungal bioconversion of lignocellulosic residues; opportunities & perspectives. Int J Biol Sci 2009; 5:578-95. [PMID: 19774110 PMCID: PMC2748470 DOI: 10.7150/ijbs.5.578] [Citation(s) in RCA: 324] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Accepted: 08/02/2009] [Indexed: 11/28/2022] Open
Abstract
The development of alternative energy technology is critically important because of the rising prices of crude oil, security issues regarding the oil supply, and environmental issues such as global warming and air pollution. Bioconversion of biomass has significant advantages over other alternative energy strategies because biomass is the most abundant and also the most renewable biomaterial on our planet. Bioconversion of lignocellulosic residues is initiated primarily by microorganisms such as fungi and bacteria which are capable of degrading lignocellulolytic materials. Fungi such as Trichoderma reesei and Aspergillus niger produce large amounts of extracellular cellulolytic enzymes, whereas bacterial and a few anaerobic fungal strains mostly produce cellulolytic enzymes in a complex called cellulosome, which is associated with the cell wall. In filamentous fungi, cellulolytic enzymes including endoglucanases, cellobiohydrolases (exoglucanases) and beta-glucosidases work efficiently on cellulolytic residues in a synergistic manner. In addition to cellulolytic/hemicellulolytic activities, higher fungi such as basidiomycetes (e.g. Phanerochaete chrysosporium) have unique oxidative systems which together with ligninolytic enzymes are responsible for lignocellulose degradation. This review gives an overview of different fungal lignocellulolytic enzymatic systems including extracellular and cellulosome-associated in aerobic and anaerobic fungi, respectively. In addition, oxidative lignocellulose-degradation mechanisms of higher fungi are discussed. Moreover, this paper reviews the current status of the technology for bioconversion of biomass by fungi, with focus on mutagenesis, co-culturing and heterologous gene expression attempts to improve fungal lignocellulolytic activities to create robust fungal strains.
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Affiliation(s)
- Mehdi Dashtban
- 1. Biorefining Research Initiative, Lakehead University, 955 Oliver Rd, Thunder Bay, Ontario, Canada, P7B 5E1
- 2. Department of Biology, Lakehead University, 955 Oliver Rd, Thunder Bay, Ontario, Canada, P7B 5E1
| | - Heidi Schraft
- 2. Department of Biology, Lakehead University, 955 Oliver Rd, Thunder Bay, Ontario, Canada, P7B 5E1
| | - Wensheng Qin
- 1. Biorefining Research Initiative, Lakehead University, 955 Oliver Rd, Thunder Bay, Ontario, Canada, P7B 5E1
- 2. Department of Biology, Lakehead University, 955 Oliver Rd, Thunder Bay, Ontario, Canada, P7B 5E1
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Moreira-Gasparin FG, de Souza CGM, Costa AM, Alexandrino AM, Bracht CK, Boer CG, Peralta RM. Purification and characterization of an efficient poultry feather degrading-protease from Myrothecium verrucaria. Biodegradation 2009; 20:727-36. [PMID: 19381452 DOI: 10.1007/s10532-009-9260-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Accepted: 03/31/2009] [Indexed: 11/27/2022]
Abstract
The purpose of this work was to characterize an alkaline protease from the filamentous fungus Myrothecium verrucaria and to explore its capability to degrade native poultry feathers. The enzyme was purified to homogeneity using a single chromatographic step. Recovery was high, 62%, with a specific activity of 12,851.8 U/mg protein. The enzyme is a small monomeric protein with a molecular mass of 22 +/- 1.5 kDa. It presented pH optimum of 8.3 and was stable over a broad pH range (5.0-12.0). The temperature optimum was 37 degrees C, with thermal stability at temperatures up to 45 degrees C. The enzyme presented an efficiency of 80.3% in the degradation of poultry feather meal, releasing amino acids and soluble peptides. It was able to hydrolyze beta-keratin without necessity of chemical or enzymatic reduction of the disulphide bonds. Considering that, everyday, poultry-processing plants produce feathers as a waste products, this protease can be useful in biotechnological processes aiming to improve the transformation of poultry feathers through solubilization of beta-keratin into usable peptides. Furthermore, it can also be useful in processes aiming to reduce the environmental pollution caused by the accumulation of feathers.
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Affiliation(s)
- Fabiana G Moreira-Gasparin
- Departamento de Bioquímica, Universidade Estadual de Maringá, Av. Colombo, 5790, Maringá, PR, 87020-900, Brazil
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69
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Generation of recombinants strains to cellulases production by protoplast fusion between Penicillium echinulatum and Trichoderma harzianum. Enzyme Microb Technol 2008. [DOI: 10.1016/j.enzmictec.2008.07.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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70
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Novel family of carbohydrate esterases, based on identification of the Hypocrea jecorina acetyl esterase gene. Appl Environ Microbiol 2008; 74:7482-9. [PMID: 18978092 DOI: 10.1128/aem.00807-08] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plant cell walls have been shown to contain acetyl groups in hemicelluloses and pectin. The gene aes1, encoding the acetyl esterase (Aes1) of Hypocrea jecorina, was identified by amino-terminal sequencing, peptide mass spectrometry, and genomic sequence analyses. The coded polypeptide had 348 amino acid residues with the first 19 serving as a secretion signal peptide. The calculated molecular mass and isoelectric point of the secreted enzyme were 37,088 Da and pH 5.89, respectively. No significant homology was found between the predicated Aes1 and carbohydrate esterases of known families, but putative aes1 orthologs were found in genomes of many fungi and bacteria that produce cell wall-degrading enzymes. The aes1 transcript levels were high when the fungal cells were induced with sophorose, cellulose, oat spelt xylan, lactose, and arabinose. The recombinant Aes1 produced by H. jecorina transformed with aes1 under the cellobiohydrolase I promoter displayed properties similar to those reported for the native enzyme. The enzyme hydrolyzed acetate ester bond specifically. Using 4-nitrophenyl acetate as substrate, the activity of the recombinant enzyme was enhanced by D-xylose, D-glucose, cellobiose, D-galactose, and xylooligosaccharides but not by arabinose, mannose, or lactose. With the use of 4-nitrophenyl-beta-D-xylopyranoside monoacetate as substrate in a beta-xylosidase-coupled assay, Aes1 hydrolyzed positions 3 and 4 with the same efficiency while the H. jecorina acetylxylan esterase 1 exclusively deacetylated the position 2 acetyl group. Aes1 was capable of transacetylating methylxyloside in aqueous solution. The data presented demonstrate that Aes1 and other homologous microbial proteins may represent a new family of esterases for lignocellulose biodegradation.
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71
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Margaritis A, Merchant RFJ, Yaguchi M. Thermostable Cellulases from Thermophilic Microorganisms. Crit Rev Biotechnol 2008. [DOI: 10.3109/07388558609150799] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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72
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Kovács K, Megyeri L, Szakacs G, Kubicek CP, Galbe M, Zacchi G. Trichoderma atroviride mutants with enhanced production of cellulase and β-glucosidase on pretreated willow. Enzyme Microb Technol 2008. [DOI: 10.1016/j.enzmictec.2008.02.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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73
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Ladisch MR, Anderson AW, Tsao GT. Measurement of Cellulolytic Activity by Low Pressure Liquid Chromatography. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/01483917908060100] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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74
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Rautio JJ, Smit BA, Wiebe M, Penttilä M, Saloheimo M. Transcriptional monitoring of steady state and effects of anaerobic phases in chemostat cultures of the filamentous fungus Trichoderma reesei. BMC Genomics 2006; 7:247. [PMID: 17010217 PMCID: PMC1617104 DOI: 10.1186/1471-2164-7-247] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Accepted: 10/02/2006] [Indexed: 12/03/2022] Open
Abstract
Background Chemostat cultures are commonly used in production of cellular material for systems-wide biological studies. We have used the novel TRAC (transcript analysis with aid of affinity capture) method to study expression stability of approximately 30 process relevant marker genes in chemostat cultures of the filamentous fungus Trichoderma reesei and its transformant expressing laccase from Melanocarpus albomyces. Transcriptional responses caused by transient oxygen deprivations and production of foreign protein were also studied in T. reesei by TRAC. Results In cultures with good steady states, the expression of the marker genes varied less than 20% on average between sequential samples for at least 5 or 6 residence times. However, in a number of T. reesei cultures continuous flow did not result in a good steady state. Perturbations to the steady state were always evident at the transcriptional level, even when they were not measurable as changes in biomass or product concentrations. Both unintentional and intentional perturbations of the steady state demonstrated that a number of genes involved in growth, protein production and secretion are sensitive markers for culture disturbances. Exposure to anaerobic conditions caused strong responses at the level of gene expression, but surprisingly the cultures could regain their previous steady state quickly, even after 3 h O2 depletion. The main effect of producing M. albomyces laccase was down-regulation of the native cellulases compared with the host strain. Conclusion This study demonstrates the usefulness of transcriptional analysis by TRAC in ensuring the quality of chemostat cultures prior to costly and laborious genome-wide analysis. In addition TRAC was shown to be an efficient tool in studying gene expression dynamics in transient conditions.
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Affiliation(s)
- Jari J Rautio
- VTT Technical Research Centre of Finland, Tietotie 2, Espoo, P.O. Box 1000, 02044 VTT-Espoo, Finland
| | - Bart A Smit
- Campina Innovation, Nieuwe Kanaal 7C, 6709 PA, Wageningen, The Netherlands
| | - Marilyn Wiebe
- VTT Technical Research Centre of Finland, Tietotie 2, Espoo, P.O. Box 1000, 02044 VTT-Espoo, Finland
| | - Merja Penttilä
- VTT Technical Research Centre of Finland, Tietotie 2, Espoo, P.O. Box 1000, 02044 VTT-Espoo, Finland
| | - Markku Saloheimo
- VTT Technical Research Centre of Finland, Tietotie 2, Espoo, P.O. Box 1000, 02044 VTT-Espoo, Finland
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75
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Mander GJ, Wang H, Bodie E, Wagner J, Vienken K, Vinuesa C, Foster C, Leeder AC, Allen G, Hamill V, Janssen GG, Dunn-Coleman N, Karos M, Lemaire HG, Subkowski T, Bollschweiler C, Turner G, Nüsslein B, Fischer R. Use of laccase as a novel, versatile reporter system in filamentous fungi. Appl Environ Microbiol 2006; 72:5020-6. [PMID: 16820501 PMCID: PMC1489370 DOI: 10.1128/aem.00060-06] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Accepted: 05/02/2006] [Indexed: 11/20/2022] Open
Abstract
Laccases are copper-containing enzymes which oxidize phenolic substrates and transfer the electrons to oxygen. Many filamentous fungi contain several laccase-encoding genes, but their biological roles are mostly not well understood. The main interest in laccases in biotechnology is their potential to be used to detoxify phenolic substances. We report here on a novel application of laccases as a reporter system in fungi. We purified a laccase enzyme from the ligno-cellulolytic ascomycete Stachybotrys chartarum. It oxidized the artificial substrate 2,2'-azino-di-(3-ethylbenzthiazolinsulfonate) (ABTS). The corresponding gene was isolated and expressed in Aspergillus nidulans, Aspergillus niger, and Trichoderma reesei. Heterologously expressed laccase activity was monitored in colorimetric enzyme assays and on agar plates with ABTS as a substrate. The use of laccase as a reporter was shown in a genetic screen for the isolation of improved T. reesei cellulase production strains. In addition to the laccase from S. charatarum, we tested the application of three laccases from A. nidulans (LccB, LccC, and LccD) as reporters. Whereas LccC oxidized ABTS (Km = 0.3 mM), LccD did not react with ABTS but with DMA/ADBP (3,5-dimethylaniline/4-amino-2,6-dibromophenol). LccB reacted with DMA/ADBP and showed weak activity with ABTS. The different catalytic properties of LccC and LccD allow simultaneous use of these two laccases as reporters in one fungal strain.
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Affiliation(s)
- Gerd J Mander
- Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany
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76
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Lee CF, Liu DYT, Lai MT, Hseu TH. Reidentification of cellulolytic enzyme-producing Trichoderma strains W-10 and G-39. Can J Microbiol 2006; 52:570-4. [PMID: 16788725 DOI: 10.1139/w06-006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Strain W-10, originally identified as Trichoderma koningii, and its supposed mutant G-39, published for production and gene expression of cellulase and xylanase, demonstrated morphological characteristics distinct from those of T. koningii, respectively. To clarify the identification derived from morphological characteristics, several methods were used, including electrophoretic karyotyping, internal transcribed spacer (ITS) analysis of rDNA, and polymerase chain reaction (PCR) fingerprinting using the universal primer L45. All the molecular characteristics showed that strains G-39 and W-10 were identical to T. reesei and T. longibrachiatum, respectively. The results strongly supported that T. koningii G-39 and W-10 should be reassigned as T. reesei and T. longibrachiatum, respectively. Strain G-39 should be considered a mutant from T. reesei QM9414 whose spores were contaminated with those of strain W-10 during a laboratory operation. According to this, we declare that T. koningii G-39 and W-10 must be renamed as T. reesei and T. longibrachiatum, respectively.Key words: PCR fingerprinting, electrophoretic karyotypes, ITS, Trichoderma.
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Affiliation(s)
- Ching-Fu Lee
- Department of Applied Science, National Hsinchu University of Education, Hsinchu, Taiwan.
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77
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Rautio JJ, Kataja K, Satokari R, Penttilä M, Söderlund H, Saloheimo M. Rapid and multiplexed transcript analysis of microbial cultures using capillary electophoresis-detectable oligonucleotide probe pools. J Microbiol Methods 2005; 65:404-16. [PMID: 16198435 DOI: 10.1016/j.mimet.2005.08.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Revised: 08/19/2005] [Accepted: 08/24/2005] [Indexed: 10/25/2022]
Abstract
A rapid assay for multiplex transcript analysis based on solution hybridization with pools of oligonucleotide probes was developed. In this assay called TRAC (transcript analysis with aid of affinity capture) the mRNAs to be studied are hybridized with gene-specific detection probe pools and biotinylated oligo(dT) and captured on streptavidin-coated magnetic particles. Unbound sample material and nonspecifically bound detection probes are removed and the target-specific probes are eluted and detected by capillary electrophoresis. Simultaneous treatment of 96 samples was automated using a magnetic bead particle processor. The assay enabled detection of in vitro transcribed RNA at the level of 30 amol (20 pg) and over a 300-fold linear range. Besides extracted RNA, crude cell lysates were directly used as samples. The assay was used for transcriptional analysis of selected mRNAs in the filamentous fungus Trichoderma reesei in two experimental conditions. TRAC analysis was highly reproducible, providing expression results that were consistent with conventional Northern blot analysis. The whole procedure starting from sample collecting can be carried out in 2 h, making this assay suitable for high-throughput analysis of a limited set of mRNAs e.g. in gene expression monitoring of production organism in microbial bioprocesses.
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78
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Thornton CR. Use of monoclonal antibodies to quantify the dynamics of alpha-galactosidase and endo-1,4-beta-glucanase production by Trichoderma hamatum during saprotrophic growth and sporulation in peat. Environ Microbiol 2005; 7:737-49. [PMID: 15819855 DOI: 10.1111/j.1462-2920.2005.00747.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Trichoderma species are ubiquitous soil and peat-borne saprotrophs that have received enormous scientific interest as biocontrol agents of plant diseases caused by destructive root pathogens. Mechanisms of biocontrol such as antibiosis and hyperparasitism are well documented and the biochemistry and molecular genetics of these processes defined. An aspect of biocontrol that has received little attention is the ability of Trichoderma species to compete for nutrients in their natural environments. Trichoderma species are efficient producers of polysaccharide-degrading enzymes that enable them to colonize organic matter thereby preventing the saprotrophic spread of plant pathogens. This study details the use of monoclonal antibodies (mAbs) to quantify the production of two enzymes implicated in the saprotrophic growth of Trichoderma species in peat. Using mAbs specific to the hemicellulase enzyme alpha-galactosidase (AGL) and the cellulase enzyme endo-1,4-beta-glucanase (EG), the relationship between the saprotrophic growth dynamics of a biocontrol strain of Trichoderma hamatum and the concomitant production of these enzymes in peat-based microcosms was studied. Enzyme activity assays and enzyme protein concentrations derived by enzyme-linked immunosorbent assay (ELISA) established the precision and sensitivity of mAb-based assays in quantifying enzyme production during active growth of the fungus. Trends in enzyme activities and protein concentrations were similar for both enzymes, during a 21-day sampling period in which active growth and sporulation of the fungus in peat was quantified using an independent mAb-based assay. There was a sharp increase in active biomass of T. hamatum 3 days after inoculation of microcosms with phialoconidia. After 3 days there was a rapid decline in active biomass which coincided with sporulation of the fungus. A similar trend was witnessed with EG activities and concentrations. This showed that EG production related directly to active growth of the fungus. The trend was not found, however, with AGL. There was a rapid increase in enzyme activities and protein concentrations on day 3, after which they remained static. The reason for the maintenance of elevated AGL probably resulted from secretion of the enzyme from conidia and chlamydospores. ELISA, immunofluoresence and immunogold electron microscopy studies of these cells showed that the enzyme is localized within the cytoplasm and is secreted extracellularly into the surrounding environment. It is postulated that release of oligosaccharides from polymeric hemicellulose by the constitutive spore-bound enzyme leads to AGL induction and could act as an environmental cue for spore germination.
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Affiliation(s)
- Christopher R Thornton
- Fungal Biology Laboratory, Washington Singer Laboratories, School of Biological and Chemical Sciences, University of Exeter, Perry Road, Exeter, Devon EX4 4QG, UK.
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79
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Boer CG, Obici L, de Souza CGM, Peralta RM. Decolorization of synthetic dyes by solid state cultures of Lentinula (Lentinus) edodes producing manganese peroxidase as the main ligninolytic enzyme. BIORESOURCE TECHNOLOGY 2004; 94:107-112. [PMID: 15158501 DOI: 10.1016/j.biortech.2003.12.015] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2002] [Revised: 12/29/2003] [Accepted: 12/30/2003] [Indexed: 05/24/2023]
Abstract
The ability of the white-rot fungus Lentinula (Lentinus) edodes to decolorize several synthetic dyes was investigated using solid state cultures with corn cob as substrate. Cultures, containing amido black, congo red, trypan blue, methyl green, remazol brilliant blue R, methyl violet, ethyl violet and Poly R478 at 200 ppm, were completely decolorized after 18 days of incubation. Partial decolorization was observed in the cultures containing 200 ppm of brilliant cresyl blue and methylene blue. High manganese peroxidase activity (2600 U/g substrate), but very low lignin peroxidase (<10 U/g substrate) and laccase (<16 U/g substrate) activities were detected in the cultures. In vitro, the dye decolorization was markedly decreased by the absence of manganic ions and H2O2. These data suggest that manganese peroxidase appear to be the main responsible for the capability of L. edodes to decolorize synthetic dyes.
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80
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Aguado J, Romero MD, Moncó G, Rodríguez L. Enzymatic hydrolysis of wheat straw: Kinetic analysis. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/abio.370130105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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81
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McCarthy JK, Uzelac A, Davis DF, Eveleigh DE. Improved catalytic efficiency and active site modification of 1,4-beta-D-glucan glucohydrolase A from Thermotoga neapolitana by directed evolution. J Biol Chem 2003; 279:11495-502. [PMID: 14660638 DOI: 10.1074/jbc.m305642200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thermotoga neapolitana 1,4-beta-d-glucan glucohydrolase A preferentially hydrolyzes cello-oligomers, such as cellotetraose, releasing single glucose moieties from the reducing end of the cello-oligosaccharide chain. Using directed evolution techniques of error-prone PCR and mutant library screening, a variant glucan glucohydrolase has been isolated that hydrolyzes the disaccharide, cellobiose, at a 31% greater rate than its wild type (WT) predecessor. The mutant library, expressed in Escherichia coli, was screened at 85 degrees C for increased hydrolysis of cellobiose, a native substrate rather than a chromogenic analog, using a continuous, thermostable coupled enzyme assay. The V(max) for the mutant was 108 +/- 3 units mg(-1), whereas that of the WT was 75 +/- 2 units mg(-1). The K(m) for both proteins was nearly the same. The k(cat) for the new enzyme increased by 31% and its catalytic efficiency (k(cat)/K(m)) for cellobiose also rose by 31% as compared with the parent. The nucleotide sequence of two positive clones and two null clones identified 11 single base shifts. The nucleotide transition in the most active clone caused an isoleucine to threonine amino acid substitution at position 170. Structural models for I170T and WT proteins were derived by sequence homology with Protein Data Bank code 1BGA from Paenibacillus polymyxa. Analysis of the WT and I170T model structures indicated that the substitution in the mutant enzyme repositioned the conserved catalytic residue Asn-163 and reconfigured entry to the active site.
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Affiliation(s)
- James K McCarthy
- Department of Biochemistry and Microbiology, Cook College, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, USA
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82
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Lenartovicz V, de Souza CGM, Moreira FG, Peralta RM. Temperature and carbon source affect the production and secretion of a thermostable β-xylosidase by Aspergillus fumigatus. Process Biochem 2003. [DOI: 10.1016/s0032-9592(02)00261-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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83
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Farani de Souza D, Giatti Marques de Souza C, Peralta RM. Effect of easily metabolizable sugars in the production of xylanase by Aspergillus tamarii in solid-state fermentation. Process Biochem 2001. [DOI: 10.1016/s0032-9592(00)00295-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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84
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Katzen R, Tsao GT. A view of the history of biochemical engineering. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2001; 70:77-91. [PMID: 11092129 DOI: 10.1007/3-540-44965-5_4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The authors present a view of biochemical engineering by describing their personal interests and experience over the years involving mostly conversion of lignocellulosics into fuels and chemicals and the associated engineering subjects.
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Affiliation(s)
- R Katzen
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
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85
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86
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Moreira FG, Lima FAD, Pedrinho SRF, Lenartovicz V, Souza CGMD, Peralta RM. Production of amylases by Aspergillus tamarii. ACTA ACUST UNITED AC 1999. [DOI: 10.1590/s0001-37141999000200014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A strain of Aspergillus tamarii, a filamentous fungus isolated from soil, was able to produce both <FONT FACE="Symbol">a</FONT>-amylase and glucoamylase activities in mineral media supplemented with 1% (w/v) starch or maltose as the carbon source. Static cultivation led to significantly higher yields than those obtained using shaking culture. The production of amylases was tolerant to a wide range of initial culture pH values (from 4 to 10) and temperature (from 25 to 42oC). Two amylases, one <FONT FACE="Symbol">a</FONT>-amylase and one glucoamylase, were separated by ion exchange chromatography. Both partially purified enzymes had optimal activities at pH values between 4.5 and 6.0 and were stable under acid conditions (pH 4.0-7.0). The enzymes exhibited optimal activities at temperatures between 50o and 60o C and were stable for more than ten hours at 55oC.
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87
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Goto CE, Barbosa EP, Kistner LC, Moreira FG, Lenartovicz V, Peralta RM. Production of amylase by Aspergillus fumigatus utilizing alpha-methyl-D-glycoside, a synthetic analogue of maltose, as substrate. FEMS Microbiol Lett 1998; 167:139-43. [PMID: 9867468 DOI: 10.1111/j.1574-6968.1998.tb13219.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
A strain of Aspergillus fumigatus isolated from soil was able to produce biomass and high amylase activities in media containing alpha-methyl-D-glucoside (alphaMG), a synthetic analogue of maltose, as the only carbon source. alphaMG was a more effective inducer than starch and maltose at the same concentration: alphaMG cultures produced about 3 times more alpha-amylase and glucoamylase activity than starch cultures. Maximum production of alpha-amylase (60 U/mg) and glucoamylase (130 U/mg) was obtained in 8-10 days alphaMG cultures.
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Affiliation(s)
- C E Goto
- Departamento de Bioquímica, Universidade Estadual de Maringá, Brazil
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88
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da Silva WB, Peralta RM. Purification and characterization of a thermostable glucoamylase fromAspergillus fumigatus. Can J Microbiol 1998. [DOI: 10.1139/w98-019] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A thermostable glucoamylase from Aspergillus fumigatus was purified to homogeneity. It was a glycoprotein with 23% carbohydrate content and an apparent molecular mass of 42 kDa. The enzyme showed maximal activities at pH 4.5-5.5 and 65°C and preferentially attacked polysacharides, such as starch, glycogen, amylopectin, and amylose, rather than maltose and maltoriose. The Kmand Vmaxof soluble starch hydrolysis at 40°C and pH 5.0 were 0.1 mg ·mL-1and 161 µmol glucose equivalents liberated ·min-1·mg protein-1, respectively. The purified enzyme was remarkably insensitive to glucose. It was not affected by 500 mM D-glucose and retained about 80% of its original activity in the presence of 1000 mM of this sugar.Key words: amylase, Aspergillus fumigatus, enzyme purification, glucose insensitive, thermostableglucoamylase.
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89
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Kadowaki MK, Souza CGM, Simão RCG, Peralta RM. Xylanase production byAspergillus tamarii. Appl Biochem Biotechnol 1997. [DOI: 10.1007/bf02788755] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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90
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Ilmén M, Saloheimo A, Onnela ML, Penttilä ME. Regulation of cellulase gene expression in the filamentous fungus Trichoderma reesei. Appl Environ Microbiol 1997; 63:1298-306. [PMID: 9097427 PMCID: PMC168424 DOI: 10.1128/aem.63.4.1298-1306.1997] [Citation(s) in RCA: 263] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Basic features of regulation of expression of the genes encoding the cellulases of the filamentous fungus Trichoderma reesei QM9414, the genes cbh1 and cbh2 encoding cellobiohydrolases and the genes egl1, egl2 and egl5 encoding endoglucanases, were studied at the mRNA level. The cellulase genes were coordinately expressed under all conditions studied, with the steady-state mRNA levels of cbh1 being the highest. Solka floc cellulose and the disaccharide sophorose induced expression to almost the same level. Moderate expression was observed when cellobiose or lactose was used as the carbon source. It was found that glycerol and sorbitol do not promote expression but, unlike glucose, do not inhibit it either, because the addition of 1 to 2 mM sophorose to glycerol or sorbitol cultures provokes high cellulase expression levels. These carbon sources thus provide a useful means to study cellulase regulation without significantly affecting the growth of the fungus. RNA slot blot experiments showed that no expression could be observed on glucose-containing medium and that high glucose levels abolish the inducing effect of sophorose. The results clearly show that distinct and clear-cut mechanisms of induction and glucose repression regulate cellulase expression in an actively growing fungus. However, derepression of cellulase expression occurs without apparent addition of an inducer once glucose has been depleted from the medium. This expression seems not to arise simply from starvation, since the lack of carbon or nitrogen as such is not sufficient to trigger significant expression.
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Affiliation(s)
- M Ilmén
- VTT Biotechnology and Food Research, Espoo, Finland
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91
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Abstract
The bacteria Fibrobacter succinogenes, Ruminococcus flavefaciens, and Ruminococcus albus generally are regarded as the predominant cellulolytic microbes in the rumen. Comparison of available data from the literature reveals that these bacteria are the most actively cellulolytic of all mesophilic organisms described to date from any habitat. In light of numerous proposals to improve microbial cellulose digestion in ruminants, it is instructive to examine the characteristics of these species that contribute to their superior cellulolytic capabilities and to identify the factors that prevent them from digesting cellulose even more rapidly. As a group, these species have extreme nutritional specialization. They are able to utilize cellulose (or in some cases xylan) and its hydrolytic products as their nearly sole energy sources for growth. Moreover, each species apparently has evolved to similar maximum rates of cellulose digestion (first-order rate constants of 0.05 to 0.08 h-1). Active cellulose digestion involves adherence of cells to the fibers via a glycoprotein glycocalyx, which protects cells from protozoal grazing and cellulolytic enzymes from degradation by ruminal proteases while it retains-at least temporarily-the cellodextrin products for use by the cellulolytic bacteria. These properties result in different ecological roles for the adherent and nonadherent populations of each species, but overall provide an enormous selective advantage to these cellulolytic bacteria in the ruminal environment. However, major constraints to cellulose digestion are caused by cell-wall structure of the plant (matrix interactions among wall biopolymers and low substrate surface area) and by limited penetration of the nonmotile cellulolytic microbes into the cell lumen. Because of these constraints and the highly adapted nature of cellulose digestion by the predominant cellulolytic bacteria in the rumen, transfer of cellulolytic capabilities to noncellulolytic ruminal bacteria (e.g., by genetic engineering) that display other desirable properties offers limited opportunities to improve ruminal digestion of cellulose.
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Affiliation(s)
- P J Weimer
- US Dairy Forage Research Center, USDA-ARS, Madison, WI 53706, USA
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92
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Ilmén M, Thrane C, Penttilä M. The glucose repressor gene cre1 of Trichoderma: isolation and expression of a full-length and a truncated mutant form. MOLECULAR & GENERAL GENETICS : MGG 1996; 251:451-60. [PMID: 8709949 DOI: 10.1007/bf02172374] [Citation(s) in RCA: 186] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The cre1 genes of the filamentous fungi Trichoderma reesei and T. harzianum were isolated and characterized. The deduced CREI proteins are 46% identical to the product of the glucose repressor gene creA of Aspergillus nidulans, encoding a DNA-binding protein with zinc fingers of the C2H2 type. The cre1 promoters contain several sequence elements that are identical to the previously identified binding sites for A. nidulans CREA. Steady-state mRNA levels for cre1 of the T. reesei strain QM9414 varied depending on the carbon source, being low on glucose-containing media. These observations suggest that cre1 expression may be autoregulated. The T. reesei strain Rut-C30, a hyper-producer of cellulolytic enzymes, was found to express a truncated form of the cre1 gene (cre1-1) with an ORF corresponding to a protein of 95 amino acids with only one zinc finger. Unlike QM9414 the strain Rut-C30 produced cellulase mRNAs on glucose-containing medium and transformation of the full-length cre1 gene into this strain caused glucose repression of cbh1 expression, demonstrating that cre1 regulates cellulase expression.
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Affiliation(s)
- M Ilmén
- VTT Biotechnology and Food Research, Espoo, Finland
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93
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Zayed G, Meyer O. The single-batch bioconversion of wheat straw to ethanol employing the fungus Trichoderma viride and the yeast Pachysolen tannophylus. Appl Microbiol Biotechnol 1996; 45:551-5. [PMID: 8737576 DOI: 10.1007/s002530050727] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We have developed and optimized a single-batch process of the production of ethanol from wheat straw employing the fungus Trichoderma viride and the yeast Pachysolen tannophylus. T. viride and Aspergillus niger were examined for their ability to produce fermentable sugars from cellulosic waste materials, e.g. different kinds of straw and wood waste. T. viride most efficiently saccharified delignified wheat straw within 3 days at 25-30 degrees C with a yield of reducing sugars of 27 g from 50 g delignified wheat straw. The resulting wheat straw hydrolysates contained xylose and glucose in a 1:1.6 molar ratio. After heat inactivation of fungal activities the sugars were converted to ethanol by the oxygen-tolerant yeast P. tannophylus in the same batch. Under the optimized conditions developed (all weights are per liter) 70 g natural untreated wheat straw (100%) yielded 50 g delignified straw (71.4%), which was saccharified to 27 g reducing sugars (38.6%). Fermentation of the sugars yielded 11.8 g ethanol (16.9%) and followed the molar equation: 1 xylose + 1.6 glucose --> 5.3 ethanol + 5.6 CO2.
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Affiliation(s)
- G Zayed
- Lehrstuhl für Mikrobiologie, University of Bayreuth, Germany
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94
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The single-batch bioconversion of wheat straw to ethanol employing the fungusTrichoderma viride and the yeastPachysolen tannophylus. Appl Microbiol Biotechnol 1996. [DOI: 10.1007/bf00578470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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95
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96
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Abstract
Trichoderma reesei has a long history of safe use in industrial-scale enzyme production. Applications of cellulases and xylanases produced by this fungus are found in food, animal feed, pharmaceutical, textile and pulp and paper industries. T. reesei is non-pathogenic for man and it has been shown not to produce fungal toxins or antibiotics under conditions used for enzyme production. During recent years genetic engineering techniques have also been used to improve the industrial production strains of T. reesei and, in addition, considerable experience of safe use of recombinant T. reesei strains in industrial scale has accumulated. Thus, T. reesei can be generally considered not only a safe production organism of its natural enzymes but also a safe host for other harmless gene products.
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Affiliation(s)
- H Nevalainen
- Research Laboratories, Alko Ltd., Helsinki, Finland
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97
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Castillo MR, Gutierrez-Correa M, Linden JC, Tengerdy RP. Mixed culture solid substrate fermentation for cellulolytic enzyme production. Biotechnol Lett 1994. [DOI: 10.1007/bf00128635] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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98
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Wey TT, Hseu TH, Huang L. Molecular cloning and sequence analysis of the cellobiohydrolase I gene from Trichoderma koningii G-39. Curr Microbiol 1994; 28:31-9. [PMID: 7764306 DOI: 10.1007/bf01575983] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The cellobiohydrolase I gene, cbh1, has been cloned from an enhanced cellulase-producing strain, Trichoderma koningii G-39. Sequence comparisons show that T. koningii cbh1 is identical to that of T. reesei with the exception of 6 bp--two causing silent substitutions in the coding region, three differing in one of the introns, and one in 5'-noncoding region. Thus, it should encode an identical CBHI to that of T. reesei despite the differences in morphological characters of the two species. Analysis of approximately 1.4 kb of the 5' flanking region shows a number of surprisingly interesting putative regulatory features. There are no unusual features within about 600 bp upstream of the translation start ATG. However, prior to the 600-bp region, there are seven CAAT sequences, a number of direct and inverted repeats, and two C/T-rich regions. Also, there are five consensus 5'-(G/C)PyGGGG-3' sequences that have been identified to be carbon catabolite repressor binding sites of Aspergillus nidulans CREA and Saccharomyces cerevisiae MIG1 repressors. The structural organization around these consensus sequence regions is similar to those of A. nidulas alcR and alcA promoters. While the production of large amounts of CBHI by T. koningii upon induction apparently correlates with the large number of CAAT boxes in the 5' upstream untranslated region of cbh1, the presence of five CREA/MIG1 repressor-binding consensus sequences in the region suggests the wide-domain carbon catabolite repression regulatory system that controls the A. nidulans ethanol regulon, and yeast GAL genes transcription might also be operative and responsible for regulation of T. koningii cbh1 transcription.
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Affiliation(s)
- T T Wey
- National Tsing Hua University, Institute of Life Science, Hsinchu, Taiwan, ROC
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99
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Flores ME, Ponce E, Rubio M, Huitr�n C. Glucose and glycerol repression of ?-amylase in Streptomyces kanamyceticus and isolation of deregulated mutants. Biotechnol Lett 1993. [DOI: 10.1007/bf00138547] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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100
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Haab D, Gassner B, Kubicek CP. Protein hypersecretory Trichoderma reesei mutant RUT C-30 displays increased ethanol and polyene resistance. J Biotechnol 1993. [DOI: 10.1016/0168-1656(93)90043-m] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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