[Studies on fermentation conditions for the accumulation of poly-beta-hydroxybutyrate in Alcaligenes eutrophus]

The results of the cultivation of Alcaligenes eutrophus showed that nitrogen limitation or exhaustion could stimulate the substantial accumulation of PHB. But the exhaustion of nitrogen source in PHB formation period would result in the rapid drop of PHB synthetic rate. Oxygen limitation could also stimulate the formation of PHB, but the content of PHB in the cell was much less than that in case of nitrogen controlled conditions. Obvious influences were observed on PHB fermentation when ammonia water feeding was stopped at different cell growth phases, and better results could be obtained when it was performed at 20 g/L to 30 g/L of residual biomass. Cell dry weight, PHB content and PHB concentration reached 61.9 g/L, 80.5% and 49.0 g/L, respectively under desired conditions.