Effect of environmental pH on chain length of lactobacillus bulgaricus

Culture medium pH was found to affect strongly the chain length of lactobacillus bulgaricus NLS-4 cells. The organism was cultured continuously in glucose-limited complex medium of different pH's with constant agitation at 250 rpm under anaerobic headspace. The cell chains increased their lengths with an increase in pH and yielded clumps of folded filaments at pH above 8.0. Involvement of an autolytic enzyme(s) in the separation of L. bulgaricus cells was confirmed, and the poor synthesis of this enzyme(s) under alkaline culture conditions could explain the pH-related filamentous growth of this organism.