Hydrolysis of amorphous and crystalline cellulose by heterologously produced cellulases of Melanocarpus albomyces

Nóra Szijártó, Matti Siika-aho, Maija Tenkanen, Marika Alapuranen, Jari Vehmaanperä, Kati Réczey, Liisa Viikari

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

Three thermostable neutral cellulases from Melanocarpus albomyces, a 20-kDa endoglucanase (Cel45A), a 50-kDa endoglucanase (Cel7A), and a 50-kDa cellobiohydrolase (Cel7B) heterologously produced in a recombinant Trichoderma reesei were purified and studied in hydrolysis (50 °C, pH 6.0) of crystalline and amorphous cellulose. To improve their efficiency, M. albomyces cellulases naturally harboring no cellulose-binding module (CBM) were genetically modified to carry the CBM of T. reesei CBHI/Cel7A, and were studied under similar experimental conditions. Hydrolysis performance and product profiles were used to evaluate hydrolytic features of the investigated enzymes. Each cellulase proved to be active against the tested substrates; the cellobiohydrolase Cel7B had greater activity than the endoglucanases Cel45A and Cel7A against crystalline cellulose, whereas in the case of amorphous substrate the order was reversed. Evidence of synergism was observed when mixtures of the novel enzymes were applied in a constant total protein dosage. Presence of the CBM improved the hydrolytic potential of each enzyme in all experimental configurations; it had a greater effect on the endoglucanases Cel45A and Cel7A than the cellobiohydrolase Cel7B, especially against crystalline substrate. The novel cellobiohydrolase performed comparably to the major cellobiohydrolase of T. reesei (CBHI/Cel7A) under the applied experimental conditions.

Original languageEnglish
Pages (from-to)140-147
Number of pages8
JournalJournal of Biotechnology
Volume136
Issue number3-4
DOIs
Publication statusPublished - Sep 10 2008

Keywords

  • Amorphous cellulose
  • Cellulase
  • Crystalline cellulose
  • Hydrolysis
  • Melanocarpus albomyces

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology

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