Construction and optimization the culture conditions for the micro storage of corn straw by lactic acid bacteria community at low temperature

Abstract:

[Objective] To optimize the culture conditions of lactic acid bacteria community (LAC-1) screened at low temperature, and investigate the micro storage effects of cornstalk inoculated with LAC-1. [Methods] The LAC-1 was screened by continuous restricted cultivation, using system pH as the only indicator. The single factor experiment, Box-Behnken design and response surface methodology were used to optimize the culture conditions of LAC-1. [Results] A community which could decrease pH rapidly was screened and named as LAC-1. LAC-1 could keep the pH and fermentation system stable, which could improve the sensory quality of fermented silage. Results showed that the pH reduction speed of LAC-1 was greatly influenced in this order: culture time, temperature and inoculated quantity. The optimal culture parameters were: culture temperature at 9.5 °C, inoculated quantity at 3.3% and culture time at 139 h. Under the optimal conditions, the fermentation time was shortened by 48 h and the number of lactic acid bacteria was increased by 20.5%. When the dry cornstalk was inoculated with LAC-1 by 5 days, the system pH fell to 4.1. The silage smelled sweet, flavor and sour, the texture was loose in appearance and bright in color. The following determination indicated the content of water-soluble carbohydrate was declined by 46.3% and the number of lactic acid bacteria was improved by 33.3%. [Conclusion] The application of LAC-1 could promote the conversion of dry cornstalk into micro storage and improve the quality of silage.