Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ 85287-5701, United States; State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ 85287-5701, United States.
Water Res. 2017 Oct 1;122:355-362. doi: 10.1016/j.watres.2017.06.017. Epub 2017 Jun 9.
Phosphorus (P) is an essential nutrient that affects the growth and metabolism of microalgal biomass. Despite the obvious importance of P, the dynamics of how it is taken up and distributed in microalgae are largely undefined. In this study, we tracked the fate of P during batch growth of the cyanobacterium Synechocystis sp. PCC 6803. We determined the distribution of P in intracellular polymeric substances (IPS), extracellular polymeric substances (EPS), and soluble microbial products (SMP) for three initial ortho-phosphate concentrations. Results show that the initial P concentration had no impact on the production of biomass, SMP, and EPS. While the initial P concentration affected the rate and the timing of how P was transformed among internal and external forms of inorganic P (IP) and organic P (OP), the trends were the same no matter the starting P concentration. Initially, IP in the bulk solution was rapidly and simultaneously adsorbed by EPS (IP) and taken up as internal IP (IP). As the bulk-solution's IP was depleted, desorption of IP became the predominant source for IP that was taken up by the growing cells and converted into OP. At the end of the 9-d batch experiments, almost all P was OP, and most of the OP was intracellular. Based on all of the results, we propose a set of transformation pathways for P during the growth of Synechocystis. Key is that EPS and intracellular P pool play important and distinct roles in the uptake and storage of P.
磷（P）是一种必需的营养物质，影响微藻生物质的生长和代谢。尽管 P 具有明显的重要性，但它在微藻中被吸收和分布的动态过程在很大程度上尚未确定。在这项研究中，我们跟踪了蓝藻 Synechocystis sp. PCC 6803 分批培养过程中 P 的去向。我们确定了三种初始正磷酸盐浓度下 P 在细胞内多聚物（IPS）、细胞外多聚物（EPS）和可溶性微生物产物（SMP）中的分布。结果表明，初始 P 浓度对生物质、SMP 和 EPS 的产生没有影响。尽管初始 P 浓度影响 P 在无机磷（IP）和有机磷（OP）的内部和外部形式之间转化的速度和时间，但无论起始 P 浓度如何，趋势都是相同的。最初，大量溶液中的 IP 被 EPS（IP）迅速且同时吸附，并被吸收为内部 IP（IP）。随着大量溶液中 IP 的消耗，IP 的解吸成为被生长细胞吸收并转化为 OP 的 IP 的主要来源。在 9 天的分批实验结束时，几乎所有的 P 都是 OP，而且大部分 OP 都在细胞内。基于所有结果，我们提出了 Synechocystis 生长过程中 P 的一系列转化途径。关键是 EPS 和细胞内 P 库在 P 的吸收和储存中发挥重要且不同的作用。
