Sustainable Bioconversion of CO2 to Polyhydroxyalkanoates Biopolymer by Anaerobic Mixed Bacteria in a Single-Stage Gas Fermentation (CO2BIOPOL)

二氧化碳（CO2）排放量的增加是造成全球变暖和气候变化的重要因素。碳捕获和利用（CCU）战略已经出现，通过气体发酵将二氧化碳转化为碳基化学物质，朝着低碳经济的方向发展。CCU的一个有趣的案例是通过厌氧微生物从二氧化碳原料中生产胞内生物聚合物，如聚羟基烷酸酯（PHA）。PHA具有多种工业和批量应用，由于其完全可生物降解和生物相容性，它已被公认为石化塑料的长期可持续绿色替代品。该项目正在开发一种新的生物技术过程的概念，通过厌氧混合微生物培养（MMC），通过使用新型高速气体转移反应器的单级气体发酵，将二氧化碳可持续地转化为PHA。首先，该项目旨在研究适宜PHA合成的厌氧微生物群落。其次，通过对操作参数的选择和控制，强化PHA的生产条件，同时提高PHA链长延伸率和厌氧MMC合成中链长的PHA。第三，优化后的PHA生产条件将在中试水平上进行评估，并进行成本效益分析，以证明单级气体发酵长期可持续生产PHA。拟议的项目在从可再生原料（二氧化碳）生产PHA方面意义重大，将成为英国和欧洲生物技术产业发展生物经济的一项资产。从二氧化碳中生产PHA将是未来可持续清洁技术的一个例子，以节省自然资源和能源。

The increasing carbon dioxide (CO2) emissions are a significant contribution to global warming and climate change. The carbon capture and utilisation (CCU) strategy has emerged to convert the CO2 to carbon-based chemicals through gas fermentation to move towards a low-carbon economy. An interesting case for CCU is to produce intracellular biopolymers such as polyhydroxyalkanoates (PHA) from CO2 feedstock by anaerobic microorganisms. PHA holds several industrial and bulk applications, and it has been recognised as long-term sustainable green alternatives to petrochemical plastics since they are entirely biodegradable and biocompatible. This project is developing the concept of a novel biotech process for the sustainable bioconversion of CO2 into PHA by anaerobic mixed microbial cultures (MMC) via single-stage gas fermentation using novel high-rate gas transfer reactors. First, the project aims to investigate the appropriate anaerobic microbial communities for PHA synthesis. Secondly, intensification of PHA production conditions by selecting and controlling operating parameters along with PHA chain length elongation and medium-chain-length PHA synthesis by anaerobic MMC. Thirdly, optimised PHA production conditions will be evaluated under pilot-scale level along with cost-benefit analysis to demonstrate the sustainable long-term PHA production via single-stage gas fermentation. The proposed project is significant in terms of PHA production from renewable feedstocks (CO2) and would be an asset in the development of the bioeconomy within UK and European biotech industries. PHA production from CO2 would be an example of sustainable future clean technologies to save natural resources and energy.