Abstract：
Despite its prominence, the ability to engineer Cupriavidus necator H16 for inorganic carbon uptake and fixation is underexplored. We tested the roles of endogenous and heterologous genes on C. necator inorganic carbon metabolism. Deletion of β-carbonic anhydrase can had the most deleterious effect on C. necator autotrophic growth. Replacement of this native uptake system with several classes of dissolved inorganic carbon (DIC) transporters from Cyanobacteria and chemolithoautotrophic bacteria recovered autotrophic growth and supported higher cell densities compared to wild-type (WT) C. necator in batch culture. Strains expressing Halothiobacillus neopolitanus DAB2 (hnDAB2) and diverse rubisco homologs grew in CO2 similarly to the wild-type strain. Our experiments suggest that the primary role of carbonic anhydrase during autotrophic growth is to support anaplerotic metabolism, and an array of DIC transporters can complement this function. This work demonstrates flexibility in HCO3- uptake and CO2 fixation in C. necator, providing new pathways for CO2-based biomanufacturing.
摘要：
尽管它很突出,对CupriavidusnecatorH16进行无机碳吸收和固定的工程能力不足。我们测试了内源性和异源基因在C.necator无机碳代谢中的作用。β-碳酸酐酶的缺失可能对C.necator自养生长具有最有害的影响。与分批培养中的野生型（WT）C.necator相比，用来自蓝细菌和化学自养细菌的几类溶解无机碳（DIC）转运蛋白替代该天然摄取系统恢复了自养生长并支持更高的细胞密度。表达新硫杆菌DAB2（hnDAB2）和各种红宝石同源物的菌株在CO2中的生长与野生型菌株相似。我们的实验表明，在自养生长过程中，碳酸酐酶的主要作用是支持回补代谢，一系列DIC转运蛋白可以补充这一功能。这项工作证明了在C.necator中HCO3-吸收和CO2固定的灵活性，为基于二氧化碳的生物制造提供新的途径。
