Biotechnology and Bioengineering, Vol.115, No.10, 2576-2584, 2018
Alka(e)ne synthesis in Cupriavidus necator boosted by the expression of endogenous and heterologous ferredoxin-ferredoxin reductase systems
To boost aldehyde deformylating oxygenase (ADO) activity in a Cupriavidus necator strain expressing a synthetic alkane pathway, the expression of two ferredoxin-ferredoxin reductase systems was tested. The genes of a native fd/FNR-like system were identified in C. necator and expressed in a previously engineered alka(e)ne producing strain. The improved production of alka(e)nes in this Re2061-pMAB1 strain confirmed the activity of the native Fd/FNR system in C. necator. Concomitantly, the expression of the heterologous system from Synechococcus elongatus was investigated identically, leading to a second strain, Re2061-pMAB2. In the bioreactor, the aldehyde production was strongly reduced compared with the original alka(e)ne producer, leading to alka(e)nes production up to 0.37 and 1.48 g/L (22 and 82 mg/g(CDW))(,) respectively. The alka(e)ne production yield of Re2061-pMAB2 accounted for 15% of the theoretical yield. We report here the highest level and yield of alka(e)nes production by an engineered bacterium to date.
Keywords:alkane;alkene;biofuels;Cupriavidus necator (C, nectator);fermentation;ferredoxin (Fd);ferredoxin reductase (FNR);hydrocarbon;metabolic engineering