Optimizing the heterologous production of epothilone D in Myxococcus xanthus

✍ Scribed by Janice Lau; Scott Frykman; Rika Regentin; Sally Ou; Hiroko Tsuruta; Peter Licari

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 219 KB
• Volume: 78
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/bit.10202

✦ Synopsis

Abstract

The heterologous production of epothilone D in Myxococcus xanthus was improved by 140‐fold from an initial titer of 0.16 mg/L with the incorporation of an adsorber resin, the identification of a suitable carbon source, and the implementation of a fed‐batch process. To reduce the degradation of epothilone D in the basal medium, XAD‐16 (20 g/L) was added to stabilize the secreted product. This greatly facilitated its recovery and enhanced the yield by three‐fold. The potential of using oils as a carbon source for cell growth and product formation was also evaluated. From a screen of various oils, methyl oleate was shown to have the greatest impact. At the optimal concentration of 7 mL/L in a batch process, the maximum cell density was increased from 0.4 g dry cell weight (DCW)/L to 2 g DCW/L. Product yield, however, depended on the presence of trace elements in the production medium. With an exogenous supplement of trace metals to the basal medium, the peak epothilone D titer was enhanced eight‐fold. This finding demonstrates the significant role of metal ions in cell metabolism and in epothilone biosynthesis. To further increase the product yield, a continuous fed‐batch process was used to promote a higher cell density and to maintain an extended production period. The optimized fed‐batch cultures consistently yielded a cell density of 7 g DCW/L and an average production titer of 23 mg/L. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 280–288, 2002.