Construction of a Starch-Inducible Homologous Expression System to Produce Cellulolytic Enzymes from Acremonium Cellulolyticus

Hiroyuki Inoue, Tatsuya Fujii, Miho Yoshimi, Larry E. Taylor, Stephen R. Decker, Seiichiro Kishishita, Makoto Nakabayashi, Kazuhiko Ishikawa

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35 Scopus Citations


A starch-inducible homologous expression system in Acremonium cellulolyticus was constructed to successfully produce recombinant cellulolytic enzymes. A. cellulolyticus Y-94 produced amylolytic enzymes and cellulolytic enzymes as major proteins in the culture supernatant when grown with soluble starch (SS) and Solka-Flock cellulose (SF), respectively. To isolate a strong starch-inducible promoter, glucoamylase (GlaA), which belongs to glycoside hydrolase family 15, was purified from the SS culture of Y-94, and its gene was identified in the genome sequence. The 1.4-kb promoter and 0.4-kb terminator regions of glaA were amplified by polymerase chain reaction (PCR) and used in the construction of a plasmid that drives the expression of the cellobiohydrolase I (Cel7A) gene from A. cellulolyticus. The resultant expression plasmid, containing pyrF as a selection marker, was randomly integrated into the genome of the A. cellulolyticus Y-94 uracil auxotroph. The prototrophic transformant, Y203, produced recombinant Cel7A as an extracellular protein under control of the glaA promoter in the SS culture. Recombinant and wild-type Cel7A were purified from the SS culture of Y203 and the SF culture of A. cellulolyticus CF-2612, respectively. Both enzymes were found to have the same apparent molecular weight (60 kDa), thermostability (T m 67.0 C), and optimum pH (pH 4.5), and showed similar catalytic properties for soluble and insoluble substrates. These results suggest that the A. cellulolyticus starch-inducible expression system will be helpful for characterization and improvement of fungal cellulolytic enzymes.

Original languageAmerican English
Pages (from-to)823-830
Number of pages8
JournalJournal of Industrial Microbiology and Biotechnology
Issue number8
StatePublished - 2013

NREL Publication Number

  • NREL/JA-2700-58551


  • Acremonium cellulolyticus
  • Cellobiohydrolase I
  • Cellulase production
  • Glucoamylase
  • Homologous expression
  • Protein expression


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