Phosphate content affecting the heterotroph population and phosphate distribution in photosynthetic biomass

The description is adapted from the manuscript we will submit for peer-reviewed journal publication.During the culturing of microalgae, heterotrophic bacteria can compete for nutrients, compromise the quality of the harvested biomass, or cause culture crashes. We systematically investigated the effects of depleting inorganic phosphate (Pi) on the growth of the cyanobacterium Synechocystis sp. PCC 6803, its community of heterotrophic bacteria, and the biomass's chemical composition. On the one hand, depleting Pi had minimal impact on the production of total biomass, extracellular polymeric substances (ESP), soluble microbial products (SMP), and most types of intracellular organic polymers. On the other hand, depleting Pi led to markedly less lipid content, less heterotrophic biomass, and a shift in the heterotrophic community from Burkholderiales to Sphingobacteriales and Saprospirales. The causes of the large impacts were that Synechocystis was much better at scavenging a very low Pi concentration and could adapt by lowering its phosphorus content. This work lays a foundation for controlling the accumulation of heterotrophs and reducing their deleterious effects in microalgae culturing.本数据集描述改编自我们拟提交至同行评议期刊的研究稿件。在微藻培养过程中，异养细菌会争夺营养物质、降低收获生物质的品质，甚至引发培养崩溃。本研究系统考察了无机磷酸盐（Pi）耗竭对蓝细菌集胞藻（Synechocystis sp. PCC 6803）及其异养细菌群落和生物质化学组成的影响。一方面，Pi耗竭对总生物质、胞外聚合物（ESP）、可溶性微生物产物（SMP）以及多数类型细胞内有机聚合物的产量影响极小；另一方面，Pi耗竭会显著降低脂质含量与异养生物质总量，并使异养群落从伯克霍尔德菌目（Burkholderiales）向鞘脂杆菌目（Sphingobacteriales）和腐螺旋菌目（Saprospirales）发生演替。该显著影响的成因在于，集胞藻在摄取极低浓度Pi方面能力更强，且可通过降低自身磷含量来适应环境。本研究为微藻培养过程中调控异养菌的增殖、削弱其有害影响奠定了理论基础。