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Novel pH control strategy
for glutathione overproduction in batch cultivation of
Candida utilis
Guobin Liang1,
Bin Wang1, Jianghui Xie2
and Yiwei Mo2*
1School
of Chemistry and Chemical Engineering, Jiangsu Teachers
University of Technology, Changzhou 213001, China.
2South
Subtropical Crop Research Institute, Chinese Academy of
Tropical Agricultural Science, Zhanjiang 524091, China.
*Corresponding author:
E-mail:
moyiwei08@yahoo.cn.
Tel:
+86-759-2859272.
Fax: +86-759-2858168.
Accepted
7 October, 2009 |
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The
effects of pH values on cell growth and glutathione (GSH)
production were studied in batch cultivation of Candida
utilis. According to the fact that lower pH value favors
cells growth but retards GSH production and higher pH value
promotes GSH production while inhibits cells growth, a
pH-shift strategy, optimized via simulating Gauss function,
was developed. By applying two-stage pH-shift strategy of
controlling pH at 5.0 for first 7.5 h and switching to 6.0
afterwards, final GSH yield and productivity reached 279 and
12.7 mg/l/h after 22 h cultivation, increased by 30 and 42%,
respectively, compared to constant pH 5.5 operation.
Moreover,
by feeding glucose instead of sulphuric acid (H2SO4)
solution to control pH, maximal GSH yield of 315 mg/l was
achieved, suggesting
application of pH-shift strategy
for GSH overproduction as being feasible.
Key
words:
Batch fermentation, Candida utilis, glutathione (GSH),
gauss function, pH-shift strategy. |
