H-2 AND POLY-BETA-HYDROXYBUTYRATE, 2 ALTERNATIVE CHEMICALS FROM PURPLE NON SULFUR BACTERIA

The feasibility of a process for the photoproduction of both H-2 and p oly-beta-hydroxybutyrate (PHB)-containing biomass has been tested util izing semi-continuous cultures of Rhodopseudomonas palustris growing i n a tubular system with limiting amounts of fixed nitrogen. A two-stag e batch process, consisting in a first period of nitrogen-limited cell growth followed by a second period of cell cultivation under conditio ns of phosphorus shortage, showed the possibility to separate the H-2 production phase from the PHB accumulation phase, making possible to c arry out processes that otherwise would be in competition.