Optimization of bovine cathepsin C production by cultivation of recombinant methylotrophic yeast Candida boidinii

Bovine cathepsin C (CTC) production from a recombinant methylotrophic yeast Candida boidinii CT714 was investigated, in which CTC gene was driven by f ormate dehydrogenase promoter and strongly induced in the presence of metha nol. Two step fermentation using DYS medium containing 1.0% (w/v) glucose f or cell growth and MYS medium containing 2.5% (v/v) methanol for inducible production of CTC was suitable for efficient production. Methanol concentra tion within 1.5 to 3.5% (v/v) was preferable for CTC induction. After 24 h of cell growth and 72 h of induction, CTC production reached approximately 12 U/l (this corresponded to 2.15 U/g-dry cells). When vitamins were enrich ed in growth medium, CTC productivity was improved more than 3 times higher , and it was found that the effective vitamins were biotin, p-aminobenzoic acid and thioctic acid.