培养条件对蓝细菌生长及PHB积累的影响

Effects of culture conditions on cyanobacterial growth and poly-β - hydroxybutyrate accumulation

对蓝细菌集胞藻 (Synechocystis) sp. PCC6 80 3的细胞生长及胞内聚 -β-羟基丁酸酯 (PHB)的积累进行了研究 ,以探索提高蓝细菌 PHB积累水平的可能性。野生型集胞藻于 BG- 11培养基中通气培养 ,改变氮源浓度、碳源种类、光照强度 ,测定细胞的生长及胞内 PHB的浓度。结果表明 :只有在氮饥饿培养时 ,胞内 PHB水平才会有明显提高。氮饥饿条件下 ,混养生长时收获的细胞量最多 ,弱光自养时细胞几乎不生长 ,两种条件下 PHB的积累水平相近 ,低于细胞干重的 0 .5 %。异养时细胞生长与混养时相近 ,PHB可积累至细胞干重的 1.0 %。强光自养最有利于 PHB的积累 ,生长 7d后可积累至细胞干重的 4.1%。该研究的结果可为进一步提高蓝细菌中

Cell growth and poly β hydroxybutyrate (PHB) accumulation in Synechocystis sp. PCC6803 were studied to find ways to improve the cyanobacterial PHB biosynthesis level. The Synechocystis sp. PCC6803 wild type strain was cultured in BG 11 medium. Cell growth and PHB content were monitored for different NaNO 3 concentrations, carbon sources and light illuminations. Only the nitrogen starved condition significantly enhanced PHB accumulation. In the nitrogen depleted conditions, the cell density in mixotrophic culture was the largest, while cells in the dark photoautotrophic culture did not show any growth. PHB accumulation was less than 0.5% of the dry cellular weight for both conditions. Cell growth in heterotrophic culture was similar to that in the light photoautotrophic culture. The PHB content in the heterotrophic culture was 1.0%. Photoautrophic growth under light provided the most favorable condition for PHB accumulation. After 7 days growth, the PHB intracellular level was up to 4.1% . The results can be used to further improve the accumulation level of cyanobacterial PHB.