Effect of Tween 80 on the morphology and physiology of Lactobacillus salivarius strain IV CL-37 grown in a chemostat under glucose limitation.

The effect of Tween 80 on Lactobacillus salivarius strain IV CL-37 growing in a chemostat under various conditions was investigated. The organisms could grow under glucose limitation in the absence of Tween 80 at pH 6.0 or lower anaerobically but not aerobically. Aerobic growth under glucose limitation and in the presence of Tween 80 occurred in complete MRS medium but not in the dialysable fraction of MRS medium. The morphology of cells differed from coccal to filamentous and branched structures according to the growth condition. The possible effect of Tween 80 on membrane components was examined by estimating the cellular and extracellular lipoteichoic acid contents. In both batch and continuous culture the amounts of cellular lipoteichoic acid were inversely related to the amount of Tween 80 whereas the amounts of extracellular lipoteichoic acid were influenced by other factors in addition to Tween 80.