ENERGY-PRODUCTION FROM L-MALIC ACID DEGRADATION AND PROTECTION AGAINST ACIDIC EXTERNAL PH IN LACTOBACILLUS-PLANTARUM CECT-220

Malate degradation by Lactobacillus plantarum CECT 220 provides energy which enables this organism to remain viable for longer at low environmental pH values. Energy production was not coupled to H+-ATPase activity. This protective mechanism against acidic external pH is complemented by another system of DELTApH maintenance. The H+-ATPase did not seem to be involved in this system of pH maintenance as the system was not sensitive to N,N'-dicyclohexylcarbodiimide (DCCD) and was functional at very low pH values where ATPase activity was severely inhibited.