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Optimizing the
production of welan gum by Alcaligenes facalis NX-3
using statistical experiment design
Sha Li, Hong
Xu*, Hui Li and Chaojiang Guo
State Key Laboratory of Materials-Oriented Chemical
Engineering, College of Food Science and Light Industry,
Nanjing University of Technology, Nanjing 210009, PR China.
*Corresponding author. E-mail:
xuh@njut.edu.cn.
Tel: +86-25-83172061. Fax: +86-25-83587326.
Accepted 26 March, 2009 |
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Welan gum is an exopolysaccharide produced by Alcaligenes
facalis
NX-3. The composition of the medium for the production of
welan gum was optimized with a stepwise strategy. Effects of
various carbon and nitrogen sources were investigated.
Plackett–Burman design was applied to elucidate the key
ingredients in the media and the results indicated that the
corn starch, cottonseed cake flour have significant effects
on welan gum production. Central composite design was
employed to search for the optimal concentration of the two
key components and the experimental results were fitted to a
second-order polynomial model at a 98% level of
significance. By solving the regression equation and also by
analyzing the response surface contour plots, the relative
high welan gum production (22.85 g l-1) was
obtained at the optimal medium combinations and fermentation
conditions as corn starch 43.6 g l-1, cottonseed
cake flour 4.1 g l-1, 16-h-old inoculum of 3% (v
v-1) sizes, initial pH 7.0 and temperature 30oC.
These predicted values were also verified by validation
experiments.
Key words:
Alcaligenes
facalis
NX-3, Medium optimization, Plackett–Burman design,
statistical experiment design, welan gum. |
