Exopolysaccharide and extracellular metabolite production by Lactobacillus delbrueckii subsp bulgaricus, grown on lactose in continuous culture

摘要

Lactobacillus delbrueckii subsp. bulgaricus NCFB 2483, when grown on lactose in continuous culture, showed increasing specific yields and volumetric productivities of exopolysaccharide (EPS) with increasing dilution rate. Specific and volumetric productivities of lactate and galactose, as extracellular metabolites, increased in response to the incremental changes in the dilution rate up to 0.4 h(-1). Elevated Y-p/s values determined for EPS (0.025 g EPS.g lactose(-1)) at the dilution rates of 0.3 h(-1)-0.4 h(-1), relative to those determined at lower dilution rates, suggest a diversion of carbon flux towards EPS being associated with the higher rates of growth. [References: 12]