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3‐Methylindole production is regulated in Clostridium scatologenes ATCC 25775
Author(s) -
Doerner K.C.,
Cook K.L.,
Mason B.P.
Publication year - 2009
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/j.1472-765x.2008.02502.x
Subject(s) - tryptophan , extracellular , food science , biochemistry , clostridium , chemistry , microbiology and biotechnology , fermentation , yeast extract , yeast , biology , bacteria , amino acid , genetics
Aims: 3‐Methylindole (3‐MI) is a degradation product of l ‐tryptophan and is both an animal waste malodorant and threat to ruminant health. Culture conditions influencing 3‐MI production in Clostridium scatologenes ATCC 25775 were investigated. Methods and Results: Extracellular 3‐MI levels in cells cultured in brain heart infusion (BHI) medium (pH 7·0) at 33°C and 37°C for 72 h were 907 ± 38 and 834 ± 121 μ mol l −1 , respectively. Cells cultured in tryptone‐yeast (TY) extract medium at 37°C for 48 h produced 104 ± 86 μ mol l −1 3‐MI; however, addition of 1 mmol l −1 l ‐tryptophan failed to increase extracellular levels (113 ± 50 μ mol l −1 3‐MI). Specific activity of indole acetic acid decarboxylase measured in BHI, TY and TY plus 1 mmol l −1 tryptophan‐grown cells displayed 35‐, 33‐ and 76‐fold higher levels than in semi‐defined medium‐grown cells. Conclusions: When cultured in rich medium, at 33°C or 37°C and pH 7·0, Cl. scatologenes ATCC 25775 optimally produced 3‐MI. Addition of l‐ tryptophan to medium did not lead to significant increases in extracellular 3‐MI levels. Whole cell assays indicate growth in rich medium significantly up‐regulated 3‐MI production. Significance and Impact of the Study: Information presented here may prove useful in understanding what factors influence 3‐MI production in malodorous animal wastes.