Trichoderma reesei strains for production of cellulases for the textile industry: Dissertation

Arja Miettinen-Oinonen

Research output: ThesisDissertationCollection of Articles


Trichoderma reesei is a biotechnically important filamentous fungus used commercially in enzyme production. T. reesei is also one of the best known cellulolytic organisms, producing readily and in large quantities a complete set of extracellular cellulases for the degradation of crystalline cellulose. In addition to T. reesei, a wide variety of other bacteria and fungi also produce cellulolytic enzymes. Cellulases originating from various organisms and having different characteristics are used industrially in many applications, such as in the textile industry in finishing of denim fabric to impart a stonewashed appearance (biostoning) and in biofinishing of cotton. In this work T. reesei strains producing significant amounts of homologous and heterologous cellulases and having defined cellulase profiles were constructed for specific industrial applications, i.e. biostoning and biofinishing of cotton. The production of T. reesei endoglucanase II (EGII), cellobiohydrolases I and II (CBHI and CBHII) was improved in separate strains. Strains producing high amounts of EGI and EGII without CBHs or CBHI and CBHII without the main EGs were also constructed. The cellulase genes were expressed under the powerful T. reesei cbh1 promoter; in a transformant overproducing both CBHI and CBHII, the cbh2 promoter was also used for cbh2 expression. The level of endoglucanase activity produced by the EGII-overproducing transformants correlated with the copy number of the egl2 expression cassette. Production of the major secreted cellulase CBHI was increased up to 1.5-fold and production of CBHII fourfold compared with the parent strain. In transformants overproducing both CBHI and CBHII, production of CBHI was increased up to 1.6-fold and production of CBHII up to 3.4-fold as compared with the host strain and approximately similar amounts of CBHII protein were produced by using the cbh1 or cbh2 promoters. The enzyme preparation with elevated EGII content most clearly improved the biostoning of denim fabric and the biofinishing of cotton fabric. Better depilling and visual appearance were achieved with the enzyme preparation having an elevated CBHII content compared to the wild type preparation in biofinishing of cotton, but the improvement was not as pronounced as in the case of the EGII preparation. Novel neutral cellulases were demonstrated to have potential in biostoning. The cellulase preparation of the thermophilic fungus Melanocarpus albomyces was found to be effective in releasing dye from indigo-dyed denim and to cause low backstaining at neutral pH. M. albomyces produces at least three cellulases and these cellulases with an effect on biostoning were purified and the genes encoding them were cloned and sequenced. Ma 20 kDa EGV (Ma Cel45A) belongs to the glycosyl hydrolase family 45 and the 50 kDa EGI (Ma Cel7A) and CBHI (Ma Cel7B) to family 7. None of the cellulases harbours a cellulose binding domain. Especially purified Ma Cel45A performed well in biostoning. The Ma cellulases were produced in T. reesei under the T. reesei cbh1 promoter for biostoning applications. The endoglucanase production levels of Ma cel45A- and cel7A-transformants were several times higher than those of the parental M. albomyces strain. The cellulase preparation produced by the recombinant Ma cel45A transformant performed well at neutral pH in the finishing of denim fabric and caused considerably less backstaining than the acid cellulase product of T. reesei.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • University of Helsinki
  • Suominen, Pirkko, Supervisor, External person
Award date5 Nov 2004
Place of PublicationEspoo
Print ISBNs951-38-6416-2
Electronic ISBNs951-38-6417-0
Publication statusPublished - 2004
MoE publication typeG5 Doctoral dissertation (article)


  • cellulase
  • cloning
  • Trichoderma reesei
  • Melanocarpus albomyces
  • homologous and heterologous gene expression
  • biostoning
  • biofinishing
  • textile industry


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