title: Effects of environmental factors on leucine catabolism by Carnobacterium piscicola.
abstract: The metabolites from leucine degradation are involved in dry fermented sausage aroma. The catabolism of leucine by a strain of Carnobacterium piscicola was studied directly in the growth medium with 3H-labelled leucine to investigate the effect of five parameters: phase of growth, pH, oxygen, glucose and alpha-ketoisocaproic acid. Resting cells (RC) were also incubated with 3H-labelled leucine. The radioactive metabolites from leucine catabolism were analysed by high performance liquid chromatography (HPLC). At pH 5.4 and 7.2, the main metabolites detected were 3-methyl butanal, 3-methyl butanol and alpha-ketoisocaproic acid. At pH 6.5, the leucine catabolism was maximum and was characterised by a high production of 3-methyl butanoic acid. Leucine catabolism was most important during the exponential phase of growth. The addition of alpha-ketoisocaproic acid at 1%, glucose at levels of 0.5% to 2% and shaking of the growth medium increased leucine catabolism.
authors.affiliation: Station de Recherches sur la Viande, Microbiologie, INRA Theix, 63122 St-Genès Champanelle, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Larrouture-Thiveyrat
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Montel
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005285:Fermentation; D005516:Food Microbiology; D005947:Glucose / Q000494:pharmacology; D006093:Gram-Positive Asporogenous Rods / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007651:Keto Acids / Q000494:pharmacology; D007700:Kinetics; D007930:Leucine / Q000378:metabolism*; D009812:Odorants / Q000032:analysis; D010100:Oxygen / Q000494:pharmacology; D014316:Tritium
chemical_list: D007651:Keto Acids; D014316:Tritium; C013082:alpha-ketoisocaproic acid; D007930:Leucine; D005947:Glucose; D010100:Oxygen