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Rapid determination of vitamin B 2 secretion by bacteria growing on solid media
Author(s) -
Salvetti S.,
Celandroni F.,
Ghelardi E.,
Baggiani A.,
Senesi S.
Publication year - 2003
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.2003.02095.x
Subject(s) - bacillus cereus , agar , microbiology and biotechnology , biology , vitamin , bacteria , lactobacillus casei , agar plate , cereus , probiotic , food science , chemistry , biochemistry , genetics
Aims: Development of an agar‐diffusion assay to measure vitamin B 2 in biological samples and application of the method to determine the amount of vitamin B 2 secreted by bacteria. Methods and Results: A riboflavin‐auxotrophic mutant of Bacillus cereus was generated by mini‐Tn 10 insertion in the ribD gene. ribD mutant sensitivity to exogenous vitamin B 2 was investigated by turbidimetric and agar‐diffusion assays. In turbidimetric assays, the B. cereus mutant displayed a similar level of sensitivity to vitamin B 2 to that of Lactobacillus casei ATCC 7469, the reference organism used for microbiological vitamin B 2 quantification. However, only the ribD mutant could be used as an indicator organism in agar‐diffusion assays. A total of eight probiotic strains, from five different probiotic formulations, were analysed by the ribD mutant‐based assay on agar plates in order to determine their ability to secrete vitamin B 2 during growth. Conclusion: The agar diffusion method with the ribD mutant of B. cereus is highly reproducible, sensitive, rapid, inexpensive, and can be applied to measure the amount of vitamin B 2 in different samples. Significance and Impact of the Study: The method developed in this study appears to be a good candidate for the screening of vitamin B 2 secretion by bacteria growing on solid media.