Monday, May 4, 2009
5-16

Cloning of Cellulase and Regulation Factor Genes in Penicillium decumbens and their expression profile analysis in glucose-repressed and cellulose-induced culture conditions

Kai Zheng, Xiaomian Wei, Guodong Liu, Yuqi Qin, Xianyun Sun, Mei Chen, and Yinbo Qu. State Key Laboratory of Microbial Technology, Shandong University, 27 Shandanan road, Jinan, 250100, China

Production cost of cellulases is critical for the effective cellulosic ethanol production processes. Penicillium decumbens 114 and its catabolite-repression-resistant mutant JU-A10, have been successfully used to produce cellulase preparations and cellulosic ethanol in industrial or pilot scale in China. Therefore, identifying the key cellulase components and elucidating the mechanisms of cellulase gene expression in this strain are very important.
Six cellulase genes (cbh1, cbh2, egl1, egl2, eg5 and bgl1), three regulation factor genes (creA and ace1, encoding repressor of cellulase and xylanase expression; xlnR, a transcriptional activator) and a swollenin gene in P. decumbens 114 were cloned by TAIL-PCR and degenerate PCR. Gene expression profiles of these cellulases and regulation factors from P. decumbens 114 in different culture conditions (glucose-repressed or cellulose-induced) were assayed. The gene expression level of EG1, EG2, EG5, CBHI and swollenin increased 70-fold, 84-fold, 179-fold, 20-fold and 19-fold respectively, in cellulose-induced culture in comparison with that of in glucose-repressed culture. Gene expression level of creA changed a little, showing creA might require some post-translational modification or interaction with some catabolite to act as a repressor. Gene expression level of aceI is down to 7.2% in cellulose-induced culture comparing with that of in glucose-repressed culture, suggesting that ACE I regulates cellulase gene by its auto-regulation. Gene expression profile of catabolite-repression-resistant mutant P. decumbent JU-A10 is also under investigation, may find some key factors which influence the difference of gene expression regulation between the two strains.

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See more of The 31st Symposium on Biotechnology for Fuels and Chemicals (May 3-6, 2009)