Date Received: 01-03-2021 / Date Accepted: 04-05-2021
This study was conducted to select, identify lactic acid bacteria strain producing enzyme -galactosidase with trans-galactosylation activity and determine the characteristics of enzyme applied in Galacto-oligosacchride (GOS) production. -galactosidase of lactic bacterial strain FV4 isolated from the fermented mustardhas been recorded as trans-galactosylation enzyme which converts lactose to GOS via the conversion product by using thin-layer chromatography (TLC).FV4 strain was identified and named Lactobacillus fermentum FV4 based on the comparison of sequence encoding for 16rRNA gene. Characterization of technical –galactosidase from this strain indicated that enzyme activity was the highest in the pH ranged from 6.5 to 8.5 and the most stable was at pH 7.5, after 24h of incubation in pH 7.5, the enzyme activity has still remained 92.8%. The optimal temperature of enzyme was 50Cand enzyme was very stable at 30Cin 24h of incubation. In addition, K+, Na+, DTT 1mM, 10mM, and Mg2+1mM activated the enzyme activity. Products of lactose conversion by using enzyme β-galactosidasewere analyzed based on TLC and HPLC showed that 65% lactose was converted to 8% GOS within 6h.
