Exploiting mixtures of H2, CO 2, and O 2 for improved production of methacrylate precursor @entity71467 by engineered XXXX strains.

@entity13099 @entity18394 @entity13100 @entity505 @entity71467 @entity29708 @entity28258
UNASSIGNED: Current manufacturing of most bulk chemicals through petrochemical routes considerably contributes to common concerns over the depletion of fossil @entity505 sources and greenhouse gas emissions. Sustainable future production of commodities thus requires the shift to renewable feedstocks in combination with established or newly developed synthesis routes. In this study, the potential of @entity28258 for autotrophic synthesis of the building block chemical @entity71467 (2-HIBA) is evaluated. A novel biosynthetic pathway was implemented by heterologous expression of the 2-hydroxyisobutyryl-coenzyme A (2-HIB-CoA) mutase from Aquincola tertiaricarbonis L108, relying on a main intermediate of strain @entity28258 's C4 overflow metabolism, @entity29708 . The intention was to direct the latter to 2-HIBA instead or in addition to @entity13099 ( @entity13100 ). Autotrophic growth and 2-HIBA (respectively, @entity13100 ) synthesis of wild-type and @entity13100 -negative mutant strains were investigated producing maximum 2-HIBA titers of 3.2  g  L(-1) and maximum specific 2-HIBA synthesis rates (q 2-HIBA) of about 16 and 175   mol  g(-1)  h(-1), respectively. The obtained specific productivity was the highest reported to date for mutase-dependent 2-HIBA synthesis from heterotrophic and autotrophic substrates. Furthermore, expression of a G protein chaperone (MeaH) in addition to the 2-HIB-CoA mutase subunits yielded improved productivity. Analyzing the inhibition of growth and product synthesis due to substrate availability and product accumulation revealed a strong influence of 2-HIBA, when cells were cultivated at high titers. Nevertheless, the presented results imply that at the time the autotrophic synthesis route is superior to thus far established heterotrophic routes for production of 2-HIBA with @entity18394 .
