To address climate change and environmental problems, it is becoming increasingly important to establish biorefineries for the production of chemicals from renewable non-food biomass. In this study, the authors report the development of Escherichia coli strains capable of overproducing a four-carbon platform chemical 4-hybroxybutyric acid (4-HB). Because 4-HB production is significantly affected by aeration level, genome-scale metabolic model-based engineering strategies were designed under aerobic and microaerobic conditions with emphasis on oxidative/reductive TCA branches and glyoxylate shunt. Several different metabolic engineering strategies were employed to develop strains suitable for fermentation both under aerobic and microaerobic conditions. It was found that microaerobic condition was more efficient than aerobic condition in achieving higher titre and productivity of 4-HB. The final engineered strain produced 103.4g/L of 4-HB by microaerobic fed-batch fermentation using glycerol. The aeration-dependent optimisation strategy of TCA cycle will be useful for developing microbial strains producing other reduced derivative chemicals of TCA cycle intermediates.
Authors: Choi S, Kim HU, Kim TY, Lee SY. ;Full Source: Metabolic Engineering. 2016 Sep 20. pii: S1096-7176(16)30137-9. doi: 10.1016/j.ymben.2016.09.004. [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][Epub ahead of print] ;[/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]