High pressure treatment of beer spoiling lactobacilli targeting molecular mechanisms of hop resistance

摘要

High pressure was used to inactivate beer spoiling lactobacilli and to elucidate their hop and acid resistance mechanisms. All investigated beer spoiling isolates were pressure sensitive. Above 100 Mpa bacterial membranes underwent phase transitions which were concomitant with inactivation HorA, HitA and non-classified multiple drug transporters conferring hop resistance. The transmembrane gradient was dissipated, hop resistance was lost and the intracelluar pH adopted the extracellular value. This strongly affected cell viability in beer. Thus, high pressure is an attractive new technology for non-thermal preservation of beer and beverages.