Selection of optimal growth medium for the synthesis of α-galactosidase from mangrove actinomycetes

Abstract

-Galactosidases ( -galactoside galactohydrolase, EC.3.2.1.22) are exoglycosidases that cleave terminal -1→6-linked galactose residues from glycoconjugates. To select best medium for the enhanced production of this enzyme by the mangrove actinomycete cultures (AGP 42 and AGP 47), four different media reported in literature were tried. The medium containing locust bean gum as the carbon source (Medium I) gave the highest level of -galactosidase activity and was selected for further studies. The actinomycete culture AGP 42 was found to give higher enzyme titers than AGP 47. A comparison of the characteristics of crude -galactosidase from these cultures showed that the enzyme from AGP 42 was active over a wider range of pH (4.0 to 8.5) compared to that from AGP 47 (pH 5.5 to 8.5). The optimum pH for the maximum -galactosidase activity from AGP 42 and AGP 47 was 7.0 and 6.4, respectively. Similarly, the optimum temperatures for both the cultures were 55 and 40°C. The enzyme from AGP 42 was found to be stable at pH range 6.0 to 7.5 and that from AGP 47 at pH range 6.0 to 7.0. Similarly, the temperature stability of -galactosidase from both the cultures was from 30 to 45°C and 30 to 40°C.