Simultaneous optimization of biomass and protease biosynthesis by a local isolated Pseudomonas sp. Part 2. Response Surface optimization using Box-Behnken design

KOTLAR CATALINA; AGÜERO MARÍA VICTORIA; ROURA SARA INES

Industrial Biotechnology

Mary Ann Liebert Inc. Publishers

Lugar: Nueva York; Año: 2010 vol. 6 p. 364 - 374

1550 9087

Response surface methodology (RSM) was used to optimize the fermentation medium for enhancing protease production by a Pseudomonas sp. In a previous work, temperature, agitation speed and salinity were found to be the factors that significantly affected protease production. While temperature, glucose content and pH were found to play the mayor influence in microorganism growth. In the present work, a Box-Behnken design was applied to determine the optimal conditions to maximize both the protease and biomass production. Empirical second-order models were determined by the multiple regression analysis of the experimental data to describe the relationship between tested variables and the responses. The determination coefficients (R2) were above 95%, which ensures the credibility of the used models. For each of the optimized medium conditions, both protease production and microbial growth kinetics were evaluated. Under the best conditions (20.07 ºC, 47.61 rpm and 2.07 g NaCl/ L), the practical protease production was 5-fold increase after 10 h of incubation. These were compared with the kinetic obtained using a biphasic system through two stage fermentation medium. First Pseudomonas sp. held inoculated under the optimal biomass conditions (25.29ºC, 3.35 g glucose/ L and pH 7.46) and then transferred to the optimal for the protease production (20.07 ºC, 47.61 rpm and 2.07 g NaCl/ L). The use of a two stage culture medium did not improve the protease production respect to the best established condition.