Anomalous anaerobic growth yields of Lactobacillus casei strain 103 in complex medium.

The value of yATP [10.5 + 2 g (dry weight) of cells/mole of adenosine triphosphate (ATP)] introduced by T. Bauchop and S. R. Elsden (J. Gen. Microbiol. 23:457, 1960) has been employed in numerous studies of microbial energy metabolism. J. Senez (Bacteriol. Rev. 26:95, 1962) has presented a detailed account of the concept and its assumptions. M. S. Oxenburgh and A. M. Snoswell (J. Bacteriol. 89:913, 1965) applied the technique to Lactobacillus plantarum ATCC 8014 and determined that its flavin-linked lactate oxidase was not coupled to ATP generation. L. casei possesses flavoprotein oxidase(s) /peroxidase(s) for reduced pyridine nucleotides; however, growth yields obtained via oxidation of growth-limiting quantities of mannitol, sorbitol, or glycerol do not indicate any additional energyyieldingover the basic Embden Meyerhof energy path (J. P. Brown, Ph.D. Thesis, Cornell Univ., Ithaca, N.Y., 1967). One strain, L. casei 103, gave unusually high growth yields from glucose under anaerobic conditions. These high yields are the subject of this report. Cells were grown in a medium composed of 1.0% tryptone, 0.5% yeast extract, and 0.2% K,HPO4. Sterile 1 M glucose was added to give the desired growth-limiting concentrations (1 to 7 gimoles/ml). Four growth conditions were employed: (i) aerobic shaken, 500-ml fluted flasks containing 100 ml placed on a gyrotary shaker; (ii) anaerobic shaken, same flask as above but fitted with gassing jets for intermittent sparging with N2; (iii) anaerobic static, 250-ml Erlenmeyer flasks filled to the neck with freshly heated and cooled medium and sealed with Vaspar plugs; (iv) aerobic static, Erlenmeyer flasks, as above, but with jets for intermittent 02 sparging. Routine analyses consisted of fiveto seven-substrate concentrations and control. After 48 hr of incubation at 32 C, cells were collected, washed with distilled