Frontiers in Microbiology · 8 authors, 3 centres
This summary was generated by AI from a single paper. It has not been reviewed by a clinician and is not clinical advice. Verify against the source before acting on it.
Researchers developed a method to select spontaneous riboflavin-overproducing mutants of Weissella cibaria by treating cultures with roseoflavin and screening for FMN riboswitch mutations. Mutant strains produced riboflavin levels from 0.80 to 6.50 mg/L compared to the wild-type level of 0.15 mg/L.
Three riboflavin- and dextran-producing Weissella cibaria strains (BAL3C-5, BAL3C-7, BAL3C-22) were treated with roseoflavin concentrations of 100, 200, 300, and 400 μg/mL to select spontaneous riboflavin-overproducing mutants. In silico RNAfold analysis predicted that most mutations would deregulate rib operon expression. Mutants were isolated by plating on dextran-supporting medium and identifying yellow mucous colonies. Recovered mutant strains produced riboflavin levels ranging from 0.80 to 6.50 mg/L, compared to the wild-type level of 0.15 mg/L. The BAL3C-5 C120T mutant was identified as the highest overproducer, and whole-genome sequencing confirmed it differed from the wild type by only this single nucleotide change. The authors note that A59C and A115G mutations produced white colonies and two minor mutations (T16G, G87A) could not be recovered. This work demonstrates that a single genomic alteration can confer a riboflavin-overproducing phenotype in lactic acid bacteria.
