UC Davis

Engineered microorganisms are capable of synthesizing essential commodity chemicals sustainably when compared to traditional petroleum-based manufacturing via metabolic engineering. Exponential population growth increasingly stresses the global food system which supplies much of the carbon feedstocks needed to support microbial product synthesis. New, underutilized carbon feedstocks must be further investigated to unlock the full potential of microbial product synthesis and support the growth of a circular bioeconomy. This dissertation will describe research efforts in the organisms Synechococcus elongatus PCC 7942 to utilize lignocellulogic lysate derived from crop waste biomass (i) to generate a final titer of 13.5 g/L 2,3-butanediol in continuous lighting conditions. This work highlights the potential benefits of utilizing multiple carbon pools at once. Additionally, cyanobacteria were engineered to utilize pure xylose (ii) to make 2,3-butanediol more efficiently. This works emphasizes potential challenges when utilizing overlooked carbon feedstocks and may suggest inherent limitations on metabolism that must be further characterized to utilize them effectively. Additionally, work engineering the microbe Escherichia coli to produce the rare sugar artificial sweetener D-allulose (iii) will be described. This multidisciplinary study exemplifies how fine-tuned dynamic regulation of metabolism is often required to make an industrially relevant consumer product at scale