Expression of HpaI in Pichia pastoris and optimization of conditions for the heparinase I production

• The recombinant Pichia pastoris strain bearing HpaI was constructed and identified.
• PCR analysis was made to confirm the integration of HpaI at yeast genome.
• The production of heparinase I was optimized by response surface methodology.
• A maximal heparinase I activity of 398.5 U/L was achieved in a 5 L fermentor.
• This study lays a good foundation for the industrial production of heparinase I.

Heparinase I has important applications in the fields of biomedicine and pharmaceuticals. The heparinase I gene (HpaI) from Flavobacterium heparinum was cloned and overexpressed in Pichia pastoris GS115, and the conditions for the heparinase I production were optimized by RSM. PCR analysis indicated that HpaI was integrated into the P. pastoris GS115 genome. The concentrations of key factors that affected the heparinase I activity were optimized, and were as follows: oleic acid, 0.07%, liquid volume in flask, 34.3 ml/L, and methanol, 0.96%. Under the optimal conditions, the activity of heparinase I was up to 323 U/L in shake flask. A maximal heparinase I activity of 398.5 U/L from the transformant 2 was achieved in a 5 L fermentor. This study demonstrates the overproduction of heparinase I by recombinant P. pastoris.