Ultraviolet Mutagenesis Combined Chemostat Enrichment Method to Screen High-temperature Resistent and High-yield Lactic Acid Bacteria

Abstract:

This paper discusses the use of ultraviolet mutagenesis combined chemostat enrichment method to screen high-temperature resistent and high-yield lactic acid bacteria. Firstly, treated a strain of Lactobacillus rhamnosus with ultraviolet rays as mutagen, and then, before plate screening, used the chemostat continuous culture method to enrich high-temperature resistent and high-yield strains at 55oC. At last we obtained nine high-temperature strains. When fermented at 55oC, the highest production of L-Lactic acid was 62.9 g/L in 48 hours, which was 18.1 g/L higher than the starting strain. It was found that this method was more efficient than direct plate screening method by a comparing experiment, greatly reducing the workload of re-screening.