Codon optimization significantly improves the expression level of a keratinase gene in Pichia pastoris

• Published in: PloS one 2013-03, Vol.8 (3), p.e58393-e58393
• Main Authors: Hu, Hong, Gao, Jie, He, Jun, Yu, Bing, Zheng, Ping, Huang, Zhiqing, Mao, Xiangbing, Yu, Jie, Han, Guoquan, Chen, Daiwen
• Format: Article
• Language: English
• Subjects: Bacillus - enzymology; Bacillus licheniformis; Bacteria; Biology; Cloning; Cloning, Molecular; Codon; Codon bias; Codons; Deoxyribonucleic acid; DNA; E coli; Enzymes; Escherichia coli; Food processing industry; Fungi; Gene Dosage; Gene expression; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Fungal; Genes; Glycosylation; Hydrogen-Ion Concentration; Hydrolysis; Industrial production; Keratin; Keratinase; Keratins - metabolism; Laboratories; Messenger RNA; Molecular weight; Mutation; Nutrition; Optimization; Optimization techniques; Peptide Hydrolases - biosynthesis; Peptide Hydrolases - genetics; pH effects; Physics; Pichia - metabolism; Pichia pastoris; Plasmids; Plasmids - metabolism; Protein expression; Proteins; Recombinant Proteins - biosynthesis; Recombinant Proteins - genetics; Substrate Specificity; Temperature; Toxins; Yeast
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0058393

The main keratinase (kerA) gene from the Bacillus licheniformis S90 was optimized by two codon optimization strategies and expressed in Pichia pastoris in order to improve the enzyme production compared to the preparations with the native kerA gene. The results showed that the corresponding mutations (synonymous codons) according to the codon bias in Pichia pastoris were successfully introduced into keratinase gene. The highest keratinase activity produced by P. pastoris pPICZαA-kerAwt, pPICZαA-kerAopti1 and pPICZαA-kerAopti2 was 195 U/ml, 324 U/ml and 293 U/ml respectively. In addition, there was no significant difference in biomass concentration, target gene copy numbers and relative mRNA expression levels of every positive strain. The molecular weight of keratinase secreted by recombinant P. pastori was approx. 39 kDa. It was optimally active at pH 7.5 and 50°C. The recombinant keratinase could efficiently degrade both α-keratin (keratin azure) and β-keratin (chicken feather meal). These properties make the P. pastoris pPICZαA-kerAopti1 a suitable candidate for industrial production of keratinases.