Open AccessBioconversion of 2‐amino acids to 2‐hydroxy acids by Clostridium butyricum
Author(s) -
Khelifa Nasser,
Dugay Annabelle,
Tessedre AnnieClaude,
Guyon François,
Rimbault Alain
Publication year - 1998
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1998.tb13318.x
Subject(s) - norvaline , clostridium butyricum , norleucine , amino acid , valine , chemistry , leucine , bioconversion , isoleucine , stereochemistry , phenylalanine , biochemistry , alanine , fermentation
Analysis by gas chromatography‐mass spectrometry (GC‐MS) of 24‐h cultures of Clostridium butyricum type strain in synthetic BMG medium supplemented with various 2‐amino acids (10 mM) revealed the presence of the corresponding 2‐hydroxy acids. C. butyricum was able to bioconvert l ‐valine, dl ‐norvaline, l ‐leucine, dl ‐norleucine, l ‐methionine and l ‐phenylalanine as well as unusual 2‐amino acids, i.e., l ‐2‐aminobutyric acid, l ‐2‐amino‐4‐pentenoic acid, dl ‐2‐aminooctanoic acid, and dl ‐2‐amino‐4‐phenylbutanoic acid. l ‐Isoleucine and cycloleucine were not converted into their corresponding 2‐hydroxy acids. The bioconversion rate was maximal with dl ‐norvaline (6.2%). Chiral GC analysis demonstrated that only d ‐2‐hydroxy‐4‐methylpentanoic acid is formed from l ‐leucine, indicating that the bioconversion is stereospecific, with inversion of configuration. d ‐Leucine and d ‐methionine were also converted to the corresponding 2‐hydroxy acids. This observation opens new aspects in the study of C. butyricum and raises questions about the amino acid metabolism by this species.