Screening of a Bacillus Strain with High Acetoin-producing Ability and Optimization of Its Fermentation Conditions
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
In order to alleviate the dependence of acetoin production on petroleum, a Bacillus strain with high yield of acetoin, greater tolerance to acidity and ethanol was screened from Nongxiang Daqu by spectrophotometry in this study. The strain with was identified as Bacillus velezensis through morphological observations and physiological and biochemical tests and by the molecular biology technique. The single factor tests and orthogonal experiments were carried out on the five fermentation conditions of the strain, including pH, temperature, liquid loading volume, inoculation amount and shaking speed. According to the range analysis, the extent of the influence of each factor on acetoin production was in the order of pH>temperature>liquid loading volume>inoculum amount>shaking speed. Response surface methodology was used to optimize the first three fermentation conditions, and the optimal fermentation conditions were obtained as follows: pH 5.46, temperature 37.30 ℃, liquid loading volume 49.20 mL, inoculum amount 5%, and shaking speed 210 r/min. Under these conditions, the average yield of acetoin by shake-flask fermentation of the strain was 25.60 g/L, which was 39.36% higher than that before optimization (18.37 g/L). The research provides guidance on the strategy of microbial production of acetoin, and the selected Bacillus velezensis has great application potential in enhancing the flavor of Baijiu.
