Expression of a Novel Chitinase Gene from Trichoderma harzianum in Saccharomyces cerevisiae

Full-length cDNA encoding endochitinase Chit37 was obtained successfully by construction of T. harzianum mycelium cDNA library and sequencing and bioinformatic analysis of the random selection clones. The results indicated that the open reading frame of Chit37 was 1, 032 bp encoding a protein of 343 amino acids and the deduced molecular weight was 36.6 kDa. The gene was amplified by PCR and then integrated into the genomic DNA of pYES2 by insertion into a single site for recombination, yielding the recombinant pYES2/Chit37 which was used to transform S. cerevisiae H158. Chitinase expressed by pYES2/ Chit37 was induced by galactose (maximal activity 0.75 units ml^-1). The enzyme activity reached the peak expression after cultured for 96 h. The optimal temperature of Chit37 is 40degC and the optimal pH is 5.0.