Original Article
Flavia Oliveira de Araujo, Luc
Abstract
The objective of this study was to investigate the production of poly-ïรโรย§- glutamic acid (ïรโรย§-PGA) by Bacillus subtilisATCC 6633, using surface response methodology. Two successive factorial designs were used to determine the sucrose concentration, addition of glutamic acid and time of culture in fermentationmediumfor the production of ïรโรย§-PGA. The results of the statistical 23 full factorial design indicated that the linear terms, sucrose concentration, addition of glutamic acid and fermentation time, were significant and positive for the production of the biopolymer. Based on these results, a central composite design was utilized in order to optimize the production of ïรโรย§-PGA and define the best concentrations of sucrose and glutamic acid and fermentation time. The best production of ïรโรย§-PGA was 20.4 g/l obtained with 132 g/l sucrose, 27.6 g/l glutamic acid and 104 h of fermentation, and the productivity for the maximal production of ïรโรย§-PGA was 0.1962 g/l.h-1.