ACCUMULATION OF POLY-BETA-HYDROXYBUTYRATE BY RHODOBACTER-SPHAEROIDES ON VARIOUS CARBON AND NITROGEN SUBSTRATES

Combinations of various carbon and nitrogen substrates were used to st udy poly-beta-hydroxybutyrate accumulation and H-2 evolution by Rhodob acter sphaeroides strain RV. The cells evolved hydrogen on lactate, py ruvate, or succinate under nitrogen-deprived conditions and on lactate -glutamate and pyruvate-glutamate media. Poly-beta-hydroxybutyrate con tent under nitrogen-sufficient and nitrogen-deprived conditions was hi ghest on acetate (up to similar to 40% of cell dry weight). Transfer o f the cells from ammonium to ammonium-free medium resulted in increase s in the poly-beta-hydroxybutyrate content on lactate and pyruvate of up to similar to 15% and similar to 20%, respectively. An increase in pH caused a decrease in H-2 production and an increase in poly-beta-hy droxybutyrate accumulation on lactate under nitrogen-deprived conditio ns. (C) 1998 Federation of European Microbiological Societies. Publish ed by Elsevier Science B.V.