Abstract：
Isoprene has numerous industrial applications, including rubber polymer and potential biofuel. Microbial methane-based isoprene production could be a cost-effective and environmentally benign process, owing to a reduced carbon footprint and economical utilization of methane. In this study, Methylococcus capsulatus Bath was engineered to produce isoprene from methane by introducing the exogenous mevalonate (MVA) pathway. Overexpression of MVA pathway enzymes and isoprene synthase from Populus trichocarpa under the control of a phenol-inducible promoter substantially improved isoprene production. M. capsulatus Bath was further engineered using a CRISPR-base editor to disrupt the expression of soluble methane monooxygenase (sMMO), which oxidizes isoprene to cause toxicity. Additionally, optimization of the metabolic flux in the MVA pathway and culture conditions increased isoprene production to 228.1 mg/L, the highest known titer for methanotroph-based isoprene production. The developed methanotroph could facilitate the efficient conversion of methane to isoprene, resulting in the sustainable production of value-added chemicals.
摘要：
异戊二烯有许多工业应用，包括橡胶聚合物和潜在的生物燃料。基于微生物甲烷的异戊二烯生产可能是一种经济有效且对环境无害的过程，由于减少碳足迹和经济利用甲烷。在这项研究中,通过引入外源甲羟戊酸（MVA）途径，对荚膜甲基球菌Bath进行了工程改造，以从甲烷中生产异戊二烯。在酚诱导型启动子的控制下，毛果杨的MVA途径酶和异戊二烯合酶的过表达大大提高了异戊二烯的产量。使用CRISPR碱基编辑器进一步设计了荚膜菌浴，以破坏可溶性甲烷单加氧酶（sMMO）的表达，氧化异戊二烯引起毒性.此外,优化MVA途径和培养条件的代谢通量可将异戊二烯的产量提高到228.1mg/L，基于甲烷营养的异戊二烯生产的已知最高滴度。开发的甲烷氧化菌可以促进甲烷向异戊二烯的有效转化，从而实现增值化学品的可持续生产。
