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Effect of alcohol feeding mode on the biosynthesis of poly (3‐hydroxybutyrate‐ co ‐3‐hyroxyvalerate)
Author(s) -
Park ChangHo,
Damodaran Vijay
Publication year - 1994
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260441106
Subject(s) - biosynthesis , alcohol , chemistry , biochemistry , stereochemistry , enzyme
An alcohol utilizing Alcaligenes eutrophus produced poly(3‐hydroxybutyrate‐ co ‐3‐hydroxyvalerate) (PHBV) copolymer under phosphate limitation. Fermentation was performed for 42−46 h in a computer‐controlled 5‐L working volume fed‐batch fermentor using ethanol and propanol as carbon sources. The culture experienced phosphate limitation in approximately 19 h. When propanol was used as a sole carbon source, 24 g/L of copolymer with 36.5 mol % of hydroxyvalerate (HV) was produced at a polymer yield of 0.41 g polymer/g alcohol (g/g) and an average polymer production rate of 0.08 g polymer/g residual biomass‐h (g/g‐h). Two experiments switching alcohol after phosphate exhaustion resulted in better polymer production (g/L), polymer yield (g/g) on alcohol, HV yield (g/g) on propanol, and average polymer production rate (g/g‐h) as compared to propanol run without alcohol switching. One switching experiment was from a mixture of 50% ethanol and 50% propanol to 100% propanol and the other experiment was from 100% ethanol to a mixture of 65% ethanol and 35% propanol. Polymer yield for these two experiments was 0.51 g/g and 0.46 g/g, respectively. However, HV mol % in the copolymer for these two runs (30.8 mol % 12.6 mol % respectively) was lower compared to propanol run without alcohol switching (3605 mol %). Direct switch from ethanol to propanol did not support cell growth and polymer production. Polymer production rate and polymer yield changed with time, and the pattern was dependent upon the alcohol feeding mode. © 1994 John Wiley & Sons, Inc.