RELEASE OF SPIROSIN ASSOCIATED WITH POTASSIUM-PHOSPHATE-INDUCED AUTOLYSIS IN LACTOBACILLUS-REUTERI-DSM-20016

We have studied the effect of medium components on spirosin production in Lactobacillus reuteri DSM 20016 to get some insight into the funct ion of spirosome in Lactobacillus. Among those investigated, only pota ssium phosphate was found to influence the production of spirosin. Tho ugh it was not effective at concentrations lower than 0.6%, it promote d the spirosin production and its accumulation into culture medium, in particular, at higher concentrations. The accumulation has been demon strated to originate in the release of spirosin due to the bacterial a utolysis induced by the higher concentrations of potassium phosphate. The autolytic effect of potassium phosphate was assumed to be a concer ted action by phosphate and potassium ions at the concentrations highe r than 0.1 and 0.4 M, respectively. A possible role of spirosin as a s ensor protein of bacterial two-component regulatory system was discuss ed.