Effect of pH on high-level diacetyl production of Enterococcus faecalis
A mutant strain KLDS 4.1003 was obtained via NTG from an Enterococcus faecalis KLDS 4.1004 which is separated from the Koumiss of Inner Mongolia. The activities of enzyme LDH and DR in KLDS 4.1003 decreased, while that of ALD was inactivated. The enzyme activities, growth statuses and metabolites of KLDS 4.1003 and KLDS 4.1004 at eight pH were determined. The yield of diacetyl in KLDS 4.1003 was the highest at pH 6.5 and 7.0, especially fermenting for 16 h. Therefore, the optimal condition of diacetyl production was at pH 7.0 for 16 h, and the highest yield was 1.29 g·L-1. The results showed that, for mutant strain KLDS 4.1003, the ability to produce diacetyl was excellent, and hence, it would be developed to an probiotic starters.
NETL
NSTL
万方数据
维普
