The results in Fig. 3 indicate that the b-galactosidase
biosynthesis in the yeast strain 17-1 was induced by lactose
available in the medium and repressed by glucose available
in the medium. It has been reported that lactose also
can induce b-galactosidase production by K. lactis and
K. fragilis [14]. This may imply that glucose derepressed
mutant of the yeast strain 17-1 could further improve the
b-galactosidase production.