Efficient Production of Recombinant Bovine Cathepsin C by High Cell Density Culture of Methylotrophic Yeast Candida boidinii.

Abstract

Bovine cathepsin C production from recombinant methylotrophic yeast, Candida boidinii, was conducted in a jar-fermentor culture of fed-batch mode. Changing the carbon source from glucose to methanol induced cathepsin C expression. After changing the carbon source, intermittent addition of methanol was effective for the production of cathepsin C. During the growth phase, the level of dissolved oxygen was kept between 40 and 80% of the saturated DO level. With this control, the lack of oxygen could be avoided and cells were grown up to ca. 50 g dry cell weight/l, approximately two fold higher than that without the DO control. However, the expression of cathepsin C in the induction phase was reduced. Half volume of the medium was replaced with the same volume of the fresh medium just before the induction. The production was improved by the medium exchange and the activity of cathepsin C in the supernatant reached over 370 U/l after 16 days of induction, corresponding to a two-fold higher value than that obtained without medium exchange.