An expression system matures: A highly efficient and cost-effective process for phytase production by recombinant strains ofHansenula polymorpha

TLDR

An efficient, low‑cost phytase production process was developed using Hansenula polymorpha. The process employs glucose or glucose syrups as the main carbon source during fermentation, with downstream processing scaled to 2000 L pilot trials. Using glucose as the carbon source reduced raw‑material costs by over 80 %, yielded up to 13.5 g/L of phytase (over 97 % of total protein), achieved >90 % downstream recovery, and demonstrated that H. polymorpha is a highly competitive, low‑cost phytase production system at pilot scale.

Abstract

An efficient process was developed for the low-cost production of phytases using Hansenula polymorpha. Glucose or glucose syrups, previously reported as repressive substrates, were used as main carbon sources during fermentation. Glucose was even the most productive substrate for high-level production of phytases. Compared with the process using glycerol, the standard carbon source used for this process until now, the use of glucose led to a reduction of more than 80% in the raw materials costs. In addition, exceptionally high concentrations of active enzyme (up to 13.5 g/L) were obtained in the medium, with phytase representing over 97% of the total accumulated protein. These levels greatly exceed those reported so far for any yeast-based expression system. Very efficient downstream processing procedures were developed with product recovery yields over 90%. Both the fermentation and downstream processing were successfully tested in pilot scale up to 2000 L. As a result, H. polymorpha can be used as a highly competitive system for low-cost phytase production. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 63: 373–381, 1999.