|
Response surface
optimization of D(-)-lactic acid production by
Lactobacillus SMI8 using corn steep liquor and yeast
autolysate as an alternative nitrogen source
Cristian J. Bolner de Lima*,
Luciana Fontes Coelho, Kate Cristina Blanco and Jonas
Contiero
Department of Biochemistry and Microbiology, Institute of
Biological Sciences, São Paulo State University, UNESP/Rio
Claro, Av. 24-A, 1515 Bela Vista, ZIP CODE 13506-900, Rio
Claro, SP, Brazil.
*Corresponding author. E-mail:
cristian@rc.unesp.br.
Tel.: +55 19 35264180.
Fax: +55 19
35264176.
Accepted
9 July, 2009 |
|
The production of D(-) lactic acid from
Lactobacillus LMI8 sp. was studied, using 2
low-cost nitrogen sources: corn steep liquor (CSL) and yeast
autolysate (YA). A central composite design was used to
determine maximal lactic acid production. The surface
response method was used to evaluate the results of the
experiments. The assays were performed in 250 mL Erlenmeyer
flasks containing 100 mL of production medium maintained
under refrigerated incubation at 200 rpm and a temperature
of 37 ± 1°C for 48 h of fermentation. Lactic acid production
was significantly affected by the isolated CSL as well as
the interaction between CSL and YA. Maximal production of
D(+) lactic acid was 41.42 g/L – a value located at the
central point, which corresponded to 15 g/L of CSL and 5 g/L
of YA.
Key
words:
D(-)-Lactic acid, Lactobacillus, corn steep liquor,
yeast autolysate, response surface methodology, medium
optimization. |
