Abstract: An efficient triglyceride-degrading bacterium BC1 was screened from the clay and was identified as Bacillus cereus. Mutant strain BC1-6 with the steady character of high triglyceride-degrading was screened by ultrasonic-DES multi-mutation on strain BC1. Its degradation rate was increased by 36.5% compared with that of strain BC1. The results showed that the optimal fermentation conditions are pH 6.5,37℃ and 160 r/min. The best carbon and nitrogen source are glucose and tryptone respectively. 1 to 5 mmol/L Fe2+ and 5 mmol/L Ca2+ could improve its degradation,but 1 to 5 mmol/L Zn2+ and Mg2+ have different inhibition effects on its degradation ability.

Key words: triglyceride, screen, degradation, multi-mutation