Isolation, identification and enzyme characteristics of a strain producing acetylesterase
一株产乙酰酯酶细菌筛选、鉴定及酶学性质研究

Objective] The aim of this study was to screen acetylesterase-producing strain and to investigate its characteristics. Methods] Anaerobic culture technique was used in screening and acclimatization of strain, and alkali lignin was a sole carbon source. The strain was identified by analyzing the sequence of 16S rDNA, Gram staining, Eosin Methylene Blue test, Methyl red test, and citrate utilization test. Acetylesterase was determined by ethyl p-nitrobenzoate. Results] Acetylesterase-producing strain RB1 was isolated from rumen fluid of beef. It was identified as Escherichia coli. The growth curve showed that 0?42 h was lag phase, 42?60 h was log phase, 60?66 h was stationary phase, and 66?86 h was death phase. The optimum temperature for the acetylesterase was 40 °C, and the optimum pH was 8.0. The highest enzyme activity was 0.52 U/mL under optimum temperature and pH, and corn stover powder as a carbon source. Conclusion] Strain RB1 was an acetylesterase-producing strain with application potential.