Molar Growth Yields and Fermentation Balances of Lactobacillus casei L3 in Batch Cultures and in Continuous Cultures

Abstract

SUMMARYFermentation balances determined for different substrates in batch and continuous cultures of Lactobacillus casei revealed two pathways of pyruvate conversion by this organism, a reduction to lactate and the phosphoroclastic cleavage. Pyruvate formed anaerobically from mannitol and citrate was split by the phosphoroclastic enzyme. Lactate was the main fermentation product formed during aerobic growth on mannitol and anaerobic and aerobic growth on glucose. In glucose-limited continuous cultures pyruvate conversion was dependent on the dilution rate. At low dilution rates glucose was fermented exclusively to acetate, ethanol and formate. At high rates only small amounts of acetate, ethanol and formate were formed and lactate production was maximal. Lactate dehydrogenase of L. casei had an absolute requirement for fructose-I,6-diphosphate and manganous ions. The specific activity of lactate dehydrogenase did not differ significantly at different dilution rates. It was concluded that the intracellular level of fructose-I ,6-diphosphate controlled the pathway of pyruvate conversion. In batch cultures YATP values were between 18-2 and 20.9. No evidence for oxidative phosphorylation was found. In continuous cultures YdTP values varied from 18.7 at low dilution rates to 23'5 at high dilution rates. From the dependence of YATP on the dilution rate, a maintenance coefficient of 1-52 x I O -~ was calculated. The YATP value corrected for energy of maintenance was 24.3. The possibility that the molar growth yields were erroneously high because of assimilation of growth substrate into intracellular polysaccharides, or because of energy yield from components of the medium other than the added energy source, was excluded.

Aerobic Utilization of Low Concentrations of Galactose by Lactobacillus plantarum

“…Lactobacillus plantarum, when grown under partial anaerobic conditions (as deep cultures) in a defined medium containing 6 to 17 pmol or I to 6 pmol galactose/ml, converted 82 or 58 %, respectively, of the galactose to lactate and gained 2.51 or 2.98 mol ATP/mol galactose (Dirar & Collins, 1972). Greater lactate production at the higher range of galactose concentrations probably resulted from a higher intracellular concentration of fructose-I ,6-diphosphate, reported by Wolin ( I 964), Anders, Jonas & Sago (I 970), deVries, Kapteijn, van der Beek &Stouthamer (1970), andBrown &Whittenberger (1972) to stimulate the activity of lactate dehydrogenases. However, when the organism was grown under aerobic conditions in the defined medium containing only I to 6,umol galactose/ml, it converted 93 % of the galactose to acetate (only 7 % to lactate) and gained 3-9 mol ATP/mol hexose.…”

Influence of salts and pH on growth and activity of a novel facultatively alkaliphilic, extremely salt-tolerant, obligately chemolithoautotrophic sufur-oxidizing Gammaproteobacterium Thioalkalibacter halophilus gen. nov., sp. nov. from South-Western Siberian soda lakes

“…This lower yield and a higher l max in soda than in NaCl ( Table 1) may indicate that the strain adopts a different strategy in the energy conservation. This phenomenon of an apparent trade-off between faster l max and higher (ATP) yield is commonly observed, both in pure cultures at different growth rates (De Vries et al 1970) as well as in physiologically similar organisms with a R-strategy as opposed to a K-strategy of survival . It is assumed that in order to grow faster, the rate of ATP production must be optimized at the expense of maximal energy conservation.…”

Effects of Glucose and Starch on Lactate Production by Newly Isolated Streptococcus bovis S1 from Saanen Goats

“…Organic acids were measured by determining the UV absorbance at 210 nm. The activities of intracellular enzymes FDP, LDH, and ␣-AMY in the supernatant were measured as follows: FDP activity by the enzymatic procedure of Racker (24) using a commercial JSAY139 FDP kit (Jie Shi Kang Biotech Co., Ltd., China), LDH activity by a method similar to that of De Vries et al (25) using a commercial kit (A020; Jiancheng Biotech Co., Ltd.), and ␣-AMY activity by an iodine-starch method (26) using a C016-1 kit (Jiancheng Biotech Co., Ltd.). The analyses were carried out following the manufacturer's protocols.…”