title: Effect of malic acid on the growth kinetics of Lactobacillus plantarum.
abstract: The fermentation kinetics of Lactobacillus plantarum were studied in a specially designed broth formulated from commercially available, dehydrated components (yeast extract, trypticase, ammonium sulfate) in batch and continuous culture. During batch growth in the absence of malic acid, the specific growth rate was 0.20 h(-1). Malic acid in the medium, at 2 mM or 10 mM, increased the specific growth rate of L. plantarum to 0.34 h(-1). An increase in the maximum cell yield due to malic acid also was observed. Malic acid in the medium (12 mM) reduced the non-growth-associated (maintenance energy) coefficient and increased the biomass yield in continuous culture, based on calculations from the Luedeking and Piret model. The biomass yield coefficient was estimated as 27.4 mg or 34.3 mg cells mmol(-1) hexose in the absence or presence of malic acid, respectively. The maintenance coefficient was estimated as 3.5 mmol or 1.5 mmol hexose mg(-1) cell h(-1) in the absence or presence of malic acid. These results clearly demonstrate the energy-sparing effect of malic acid on the growth- and non-growth-associated energy requirements for L. plantarum. The quantitative energy-sparing effect of malic acid on L. plantarum has heretofore not been reported, to our knowledge.
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, and North Carolina Agricultural Research Service, Department of Food Science, N.C. State University, Raleigh, NC 27695-7624, USA. fvpassos@ufv.br
authors.forename: F V
authors.initials: FV
authors.lastname: Passos
authors.forename: H P
authors.initials: HP
authors.lastname: Fleming
authors.forename: H M
authors.initials: HM
authors.lastname: Hassan
authors.forename: R F
authors.initials: RF
authors.lastname: McFeeters
mesh_terms: D018553:Cucumis sativus / Q000378:metabolism / Q000382:microbiology; D003470:Culture Media; D005285:Fermentation; D007700:Kinetics; D007778:Lactobacillus / Q000187:drug effects* / Q000254:growth & development*; D008293:Malates / Q000494:pharmacology*
chemical_list: D003470:Culture Media; D008293:Malates; C030298:malic acid