Continuous bioconversion of n-octane to octanoic acid by recombinant Escherichia coli (alk+) growing in a two-liquid-phase Chemostat
✍ Scribed by Oliver Favre-Bulle; Erik Weenink; Tera Vos; Hans Preusting; Bernard Witholt
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 1001 KB
- Volume
- 41
- Category
- Article
- ISSN
- 0006-3592
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✦ Synopsis
Abstract
Escherichia coli is able to grow on sugars in the presence of a bulk n‐alkane phase. When E. coli is equipped with the alk genes from Pseudomonas oleovorans, the resulting recombinant strain converts n‐alkanes into the corresponding alkanoic acids. To study the effects of growth rate and exposure to a bulk apolar phase on the physiology and the productivity of E. coli, we have grown this microorganism in two‐liquid‐phase continuous cultures containing 5% (v/v) n‐octane.
In contrast to batch cultures of wild‐tape E. coli grown in the presence of n‐octane, cells remained viable during the entire continuous culture, which lasted 200 h. Bioconversion of n‐octane to n‐octanoic acid by a recombinant E. coli (alk^+^) in a two‐liquid‐phase continuous culture was made possible by optimizing both the recombinant host strain and the conditions of culturing the organism. Continuous production in such two‐phase systems has been maintained for the least 125 h without any changes in the product concentration in the fermentation medium. The volumetric productivity was determined as a function of growth rate and showed a maximum at a dilution rate D = 0.32 h^−1^, reaching a continuous production rate of 0.5 g octanoate/L · h (4 tons/m^3^ · year). © 1993 John Wiley & Sons, Inc.