IMMOBILIZATION OF NITROGEN-FIXING BACILLUS FLEXUS STRAIN BLY01 FOR ENHANCED SYNTHESIS OF α-AMYLASE AND ALKALINE PHOSPHATASE

Abstract

A nitrogen-fixing gram positive spore forming bacteria was isolated from potato waste and produced α-amylase and alkaline phosphatase (APase) when the organism had been fed on starch and insoluble Ca2(PO4)3 in nitrogen free medium. The organism was identified as Bacillus flexus BLY01 on the basis of morphological as well as phylogenetic analysis using 16S rDNA sequencing. Under optimized conditions in broth culture, fresh cells produced about 56 unit/ml of α-amylase and 16.75 unit/ml of alkaline phosphatase. The log phase cells of strain BLY01 had been immobilized in Ca-alginate gel capsules and were used for the semi-continuous production of the substrate specific enzymes individually. The immobilized cells showed about 27% and 126% enhancement in activity of α-amylase and APase, respectively. The immobilized system retained 80% - 84% of its initial efficiency after 3rd cycle of fermentation batches.
One unit of α-amylase activity = 10 µg of reducing sugar per ml per min from soluble starch and one unit of APase =10 µg of para-nitrophenol formed per ml per min at 370C at pH 8.0.