Using Xinjiang Kazakh cheese samples as
the
raw materials, 9 strains producing β-galactosidase
are found
through blue
-
white screening. The hydrolytic activity of β-galactosidase
is
measured by shake
-
flask fermentation, and a strain y-2 with high enzyme activity
i
s selected and identified as Kluyveromyces marxianus. By studying the influence of temperature, pH, wall breaking time, lactose concentration, metal ions and inoculation amount on the enzyme activity of the strain, the production of β-galactosidase in the synthetic medium is optimized. The regression statistical analysis of response surface method is conducted through single factor experiment. The results show that the activity of β-galactosylase produced by Kluyveromyces marxianus is the highest at 37 ℃, pH 7, wall breaking time 5 min, K+ as a growth factor at the concentration of 0.001 g/L, 10% lactose and 4% inoculation amount.