Photoheterotrophy for economical production of bioplastics from municipal organic waste: Integration of polyphosphate metabolism and P-recovery chemistry to maximize PHA yields

城市废水和有机固体废物工业正在经历一场资源回收革命。利用废弃物生产有用的生物材料具有巨大的经济效益和环境效益。生产的重要生物材料包括生物塑料前体聚羟基链烷酸酯（PHA）和磷（P）矿物碳酸盐磷灰石（即，磷酸盐岩）用于肥料。本研究将开发一种利用红外高效混合微生物工艺--利用光合异养紫色非硫细菌（PNSB）合成PHA并浓缩磷，然后应用结晶理论捕集磷。目前PHA生产的技术经济研究表明，混合培养物比饲喂灭菌原料的纯培养物更经济。因此，我们的项目将提供成本降低和最终产品的多功能性。我们的工业合作伙伴将获得基于PNSB的颠覆性技术的新知识，以继续开发未来的产品线，并为回收资源提供多个市场渠道。加拿大的废水处理设施将获得一个有效的资源回收过程，适应寒冷的冬天。加拿大也将受益于用于化肥生产的可再生磷资源，因为加拿大唯一的磷矿已于2013年关闭。这些新工艺将有助于减少温室气体排放，并帮助加拿大实现其可持续发展和粮食安全目标。 该工艺将利用PNSB的高效光合营养代谢，从稀释的城市污水中浓缩磷酸盐并产生生物质。在废水中生长的PNSB生物质将使用新的高强度照明方法富集PHA积累，这也将诱导聚磷酸盐的积累。在单独的步骤中，多磷酸盐将从PNSB中释放并通过新的碳酸盐磷灰石结晶过程捕获。P限制的生物质将用于使用由有机废物发酵产生的挥发性脂肪酸的PHA合成。拟议的研究将阐明适当的反应器条件，以最大限度地提高PHA和多磷酸盐积累代谢PNSB。该项目将培养12名HQP：2名博士，3名工程硕士，1名博士后和6名本科生。

The municipal wastewater and organic solids waste industries are undergoing a resource recovery revolution. Producing useful biomaterials from wastes promises great economic and environment benefits. Important biomaterials to produce include the bioplastic precursor polyhydroxyalkanoate (PHA), and the phosphorus (P) mineral carbonate apatite (i.e., phosphate rock) used in fertilizers. We will develop a new highly efficient mixed microbial process harnessing infrared-using photoheterotrophic purple non-sulfur bacteria (PNSB) to synthesize PHA and concentrate P; then, to apply crystallization theory for P capture. Current techno-economic studies of PHA production suggest that mixed cultures are more economical than pure cultures fed sterilized feedstocks. Thus, our project will provide cost reduction, and end-product versatility. Our industrial partner will gain new knowledge of PNSB-based disruptive technologies to continue developing future product lines with several market outlets for recovered resources. Canadian wastewater treatment facilities will gain an efficient resource recovery processes adapted to cold winters. Canada would also benefit from a renewable source of P for fertilizer production, as the only Canadian phosphate mine closed in 2013. These new processes will help reduce greenhouse gas emissions and help Canada meet its sustainability and food security targets. The proposed process will take advantage of the efficient photoherotrophic PNSB metabolism to concentrate phosphate and produce biomass from dilute municipal wastewater. The PNSB biomass grown in wastewater will be enriched for PHA accumulation using a new high intensity illumination method, which will also induce the accumulation of polyphosphate. In a separate step, the polyphosphate will be released from the PNSB and captured by a new carbonate apatite crystallization process. The P-limited biomass will be used for PHA synthesis using volatile fatty acids generated from the fermentation of organic waste. The proposed research will elucidate the proper reactor conditions to maximize the PHA and polyphosphate accumulation metabolisms by PNSB. The project will train a total of 12 HQP: 2 PhD, 3 MEng, 1 postdocs, and 6 undergrads.