Stimulatory effect of manganese and glycine derivatives on production and release of β-galactosidase by alkalophilic Bacillus no. C-125

Abstract

Mn2+, glycine, glycine derivatives, amino acid analogues, and D-amino acids were investigated for their role in the production and release of β-galactosidase by alkalophilic Bacillus no. C-125. The simultaneous addition of Mn2+ and either glycine methyl ester, glycine ethyl ester, or glycinamide markedly increased the production and release of the enzyme. The addition of more than 100 μM Mn2+ was indispensable for increased enzyme production and release even in a nutrient-rich medium. When both Mn2+ and 2.0% glycine ethyl ester were added simultaneously, the maximum cell mass increased 3.6-fold, the maximum total activity, 19.8-fold, and 65% of the total activity was found extracellularly. Protease production was stimulated by Mn2+ but repressed by glycine ethyl ester. The simultaneous addition of Mn2+ and 2.0% glycine ethyl ester repressed protease activity strongly. The extracellular protein: nucleic acid ratio was higher in the presence of both Mn2+ and glycine ethyl ester, indicating that this method is advantageous for practical application to extracellular accumulation of intracellular proteins. The simultaneous addition of Mn2+ and glycine ethyl ester to the medium decreased the stability of protoplasts, especially at alkaline pH.