Institute of Applied Microbiology-iAMB, Aachen Biology and Biotechnology-ABBt, RWTH Aachen University, Aachen, Germany.
Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan.
Biotechnol Bioeng. 2020 Jul;117(7):2089-2099. doi: 10.1002/bit.27337. Epub 2020 Apr 4.
Inorganic polyphosphate (polyP) is the polymer of phosphate. Water-soluble polyPs with average chain lengths of 2-40 P-subunits are widely used as food additives and are currently synthesized chemically. An environmentally friendly highly scalable process to biosynthesize water-soluble food-grade polyP in powder form (termed bio-polyP) is presented in this study. After incubation in a phosphate-free medium, generally regarded as safe wild-type baker's yeast (Saccharomyces cerevisiae) took up phosphate and intracellularly polymerized it into 26.5% polyP (as KPO , in cell dry weight). The cells were lyzed by freeze-thawing and gentle heat treatment (10 min, 70°C). Protein and nucleic acid were removed from the soluble cell components by precipitation with 50 mM HCl. Two chain length fractions (42 and 11P-subunits average polyP chain length, purity on a par with chemically produced polyP) were obtained by fractional polyP precipitation (Fraction 1 was precipitated with 100 mM NaCl and 0.15 vol ethanol, and Fraction 2 with 1 final vol ethanol), drying, and milling. The physicochemical properties of bio-polyP were analyzed with an enzyme assay, P nuclear magnetic resonance spectroscopy, and polyacrylamide gel electrophoresis, among others. An envisaged application of the process is phosphate recycling from waste streams into high-value bio-polyP.
无机多聚磷酸盐（polyP）是磷酸盐的聚合物。平均链长为 2-40 个 P 亚基的水溶性多聚磷酸盐被广泛用作食品添加剂，目前通过化学方法合成。本研究提出了一种环保、高可扩展的方法，用于生物合成可溶于水的食品级粉末状多聚磷酸盐（称为生物多聚磷酸盐）。在无磷酸盐培养基中孵育后，通常被认为是安全的野生型面包酵母（酿酒酵母）吸收磷酸盐，并在细胞内将其聚合成长度为 26.5%的多聚磷酸盐（以 KPO 形式存在，占细胞干重的 26.5%）。细胞通过冻融和温和热处理（10 分钟，70°C）裂解。通过用 50mM HCl 沉淀可溶性细胞成分来去除蛋白质和核酸。通过多聚磷酸盐分级沉淀（用 100mM NaCl 和 0.15 体积乙醇沉淀 Fraction 1，用 1 最终体积乙醇沉淀 Fraction 2），干燥和研磨，获得了两种链长分数（平均 42 和 11 个 P 亚基的多聚磷酸盐链长，与化学合成的多聚磷酸盐纯度相当）。通过酶测定、P 核磁共振波谱和聚丙烯酰胺凝胶电泳等方法分析了生物多聚磷酸盐的理化性质。该工艺的预期应用是从废物流中回收磷酸盐，制成高价值的生物多聚磷酸盐。
