Cultural condition affecting the growth and production of β-galactosidase by Bifidobacterium longum CCRC 15708 in a jar fermenter

In the present study, the growth and production of β-galactosidase by Bifidobacterium longum CCRC 15708 in a 5-L jar fermenter as influenced by cultivation temperature (27–42 °C), medium pH (4.5–7.5) and agitation speed (5–200 rpm) were evaluated.In general, it was found that a cultivation temperature of 37 °C proved optimal for both growth and β-galactosidase production by the test organism. Although the growth of the test organism was the highest in the culture with pH controlled at 4.5–6.5, the culture with pH controlled at 6.5 resulted in the highest production of β-galactosidase. Further, agitation at 100 rpm or more was found to enhance both the growth and production of β-galactosidase.Fermentation conducted in a jar fermenter having the pH of the culture medium, the cultivation temperature, and the agitation speed controlled at 6.5, 37 °C, and 100 rpm, respectively, a maximum β-galactosidase activity of 36.7 U/ml and a maximum transgalactosylation activity of 0.49 U/ml was achieved in 10 h of fermentation. There are ca 2.0 and 12.3 fold greater than the reported maximum β-galactosidase and transgalactosylation activity, respectively, produced by B. longum CCRC 15708 in a flask culture system.