Evaluation of α-galactosidase biosynthesis by Streptomyces griseoloalbus in solid-state fermentation using response surface methodology

Aim: The present study was aimed at evaluating the effects of the three crucial factors, galactose concentration, inoculum size and moisture content, on alpha-galactosidase production by the filamentous actinobacterium Streptomyces griseoloalbus in solid-state fermentation. Methods and Results: Central Composite design was adopted to derive a statistical model for the optimization of fermentation conditions. Maximum alpha-galactosidase yield (117 U g(-1) of dry fermented substrate) was obtained when soya bean flour supplemented with 1.5% galactose and with initial moisture content of 40% was inoculated with 1.9 x 10(6) CFU g(-1) initial dry substrate. Conclusions: The model was valid and could result in considerably enhanced enzyme yield. Significance and Impact of the Study: The results indicated a cost effective method for the production of alpha-galactosidase using soya bean flour. This is the first report on exploitation of the potential of filamentous bacterium for the production of alpha-galactosidase, an enzyme having versatile applications.