High Expression of Human Cathepsin S by Recombinant < b > < i > Pichia pastoris < /i > < /b > with Cod Skin as an Organic Co-Nitrogen Source

Human cathepsin S production by recombinantPichia pastoris using cod skin as the co-nitrogen source was investigated in this study. The addition of carbon sources of glycerol in the fed-batch phase and of methanol in the induction stage was also investigated. A new approach to the highly expression of human cathepsin S was developed using 90 g/L of cod skin (wet weight). After 24 h of the initial fermentation, 4% glycerol (v/v, glycerol/culture) was added once to enhance the cell density (OD600) in the cultivation. Then, adding and maintaining methanol at 0.5% (v/v, methanol/cultivation) after about 48 h of fermentation achieved a high expression of human cathepsin S in a 5-L bioreactor. The results demonstrate that the maximum activity of human cathepsin S in the fermentation supernatant reached 7,152 U/L after 96 h of methanol induction. The methylotrophic yeastP. pastoris grown in the medium containing cod skin (90 g/L) as the co-nitrogen source provided a 21% higher cell density (OD600) and 18.3% higher human cathepsin S yield thanP. pastoris grown in BMGY medium. For the first time, human cathepsin S was successfully expressed byP. pastoris with cod skin as the co-nitrogen source. The glycerol fed-batch controlling strategy and method of maintaining methanol at a constant concentration of 0.5% (v/v, methanol/cultivation) in the induction stage was efficient forP. pastoris growth and the expression of human cathepsin S.J Mol Microbiol Biotechnol 2017;27:363 –370
Source: Journal of Molecular Microbiology and Biotechnology - Category: Microbiology Source Type: research