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Enhanced β‐galactosidase production by high cell‐density culture of recombinant Bacillus subtilis with glucose concentration control
Author(s) -
Park Yong Soo,
Kai Kenichi,
Iijima Shinji,
Kobayashi Takeshi
Publication year - 1992
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.260400607
Subject(s) - bacillus subtilis , fed batch culture , propionate , enzyme , recombinant dna , biochemistry , chemistry , sodium propionate , enzyme assay , chromatography , cell culture , l glucose , biology , fermentation , bacteria , microbiology and biotechnology , genetics , islet , gene , insulin
Cell concentration, recombinant protein (β‐galactosidase) level, and the specific enzyme expression level were increased from 19 to 184 g/L, 18.3 to 129 U/mL, and 3.2 to 5.7 U/mg protein, respectively, in fed‐batch culture of recombinant Bacillus subtilis when glucose concentration was controlled at 1 g/L as compared with those of conventional fed‐batch culture. Glucose concentration of the culture broth was monitored by an automatic on‐line glucose analyzer and controlled with a moving identification combined with optimal control (MICOC) strategy. When glucose concentrations were controlled at 10, 1, and 0.2 g/L, accumulated propionic acid concentrations and specific enzyme activities were 18.5, 4.4, and 0.6 g/L and 2.9, 5.7, and 7.1 U/mg protein, respectively. The addition of various concentrations of sodium propionate to the growth medium in batch cultures resulted in a drastic decrease in the growth rate with respect to propionate concentration. The propionic acid was shown to be responsible for cell growth inhibition and enzyme activity reduction in fed‐batch culture. © 1992 John Wiley & Sons, Inc.