Abstract

The aim of this study was various nutrients belonging to three categories, carbon, nitrogen and amino acid sources, were investigated in terms of their effect on the production of extracellular β-galactosidase by Bacillus licheniformis ATCC 12759. Amongst simple carbon sources, xylose and galactose supported maximum β-galactosidase production.Comparison with the control there was significant increase in enzyme yield in the case of the supplementation complex carbon source such as rice flour. Among the amino acid sources tested L-tryptophane, L-cysteine, L-phenylalanine, L-lysine, L-valine and L-tyrosine were favored the production respectively. In media containing the all organic and inorganic nitrogen sources resulted in a decrease production of β-galactosidase. FeSO₄, ZnSO₄ and CuSO₄ supressed β-galactosidase production. Maximum β-galactosidase production (2.508.3 ± 29.9 U/mg) was obtained in a medium containing 0.01% L-tryptophane in 72 h 37°C.

Key words: Bacillus licheniformis ATCC 12759, β-galactosidase, submerged fermentation, enzyme production.