Production of 3-galactosidase enzyme from Some Microorganisms

Abstract

Abstract 8-D-Galactosidase (3-D-galactoside galactohydrolase, E.C. 3.2.1.23), is one of the most important enzymes used in food processing. It a specific example of a gly-cosidase enzyme. Many organisms naturally synthesize 3-galactosidase, including microorganisms, plant and animal cells. Among these possibilities, microbial sources are the best. Although the commercial -Galactosidase can be obtained from microorganisms dif-ferent genera, there is still a need to screening new strain that produce 3-gal in high yield to cover the increasing industry demand of this enzyme. It is well known that variations in media components in a culture media have an essential role in influencing. microbial cell growth and thereby enzyme production. In the light of what recent, the aim of the present research was the production of 3-Galactosidase using defined medium by E.coli cultivation at 37C, 125 rpm and PH-7. 3-galactosidase production by E.coli strains was initially investigated in shake flask culture, and thereafter, production was scaled up to hatch and fed-batch culture. Evaluating all strains belonging to E.coli genus E.coli (DSM 498, DH5a and TOP10) were used in the shake flask culture, to find out the best strain for scale up production, was done by measuring the influence of different defined media ((ie. DM I, DM II DM III)) on the bacterial growth and 3-galactosidase production. Shake flask studies revealed that the optimum defined medium and E.coli strain among those differ studied for the further scale up were E.coli DSM 498 and DM (II). The maximum growth was obtained with the combination (E.coli DSM 498, DM II) The culture medium (II) with lactose presented the maximum OD 6.6 and also the maximum beta galactosidase amount (6.1 u/ml). For the scale up production in batch and fed batch fermentation, studied strain showed higher activity of produced 3-galactosidase in defined medium by batch fermentation. than complex medium. The microbial growth was higher in DM medium compared with CM (OD about 1.5, biomass about 1.7) also the beta galactosidase activity which was higher by about 5 folds than CM. Whereas in fed batch fermentation, our result showed that the E.coli DSM 498 pre-sented OD value 54.60 and dry hiomass 25 (g/1) were higher than those achieved with batch fermentation by using the same defined medium (about 3.5 fold); also the beta galactosidase activity was 5.7 folds higher than that obtained by batch cultiva-tion. In conclusion, E.coli DSM 498 presented not only higher growth and cell density in defined medium than CM but also a higher beta galactosidase activity. This is lead for further optimization studies of production to be successfully introduced in commercial field.