FACTORS AFFECTING POLYHYDROXYBUTYRATE BIOSYNTHESIS IN THE MARINE PHOTOSYNTHETIC BACTERIUM RHODOPSEUDOMONAS SP STRAIN W-1S

A marine photosynthetic bacterium, Rhodopseudomonas sp. strain W-1S, a ccumulated polyhydroxybutyrate (PHB) to 56% of the dry cell weight und er microaerobic and photoheterotrophic conditions. The addition of NaC l and phosphate was essential for the accumulation. Acetate was the be st carbon source for PHB accumulation, whereas adding malate, succinat e, or sugars that did not support the growth in this strain resulted i n no accumulation. The strain accumulated PHB to about 50% of the dry cell weight at the logarithmic phase of growth. These results suggeste d that the accumulation would be growth associated under microaerobic and photoheterotrophic conditions. Vitamins, especially biotin, exerte d an inhibitory effect on PHB accumulation and a stimulatory effect on pigment production. There might be regulation of carbon flux to PHB o r pigments as storage materials.