(597a) Balancing Kinetic and Thermodynamic Barriers to Isomerization Catalysis in Probiotic Lactobacillus Plantarum
AIChE Annual Meeting
Thursday, November 1, 2018 - 8:00am to 8:18am
In this work, we use the mesophilic and acid tolerant L-arabinose isomerase (LAI/AraA) from Lactobacillus sakei in probiotic Lactobacillus plantarum as a model system to study D-tagatose production. We confirmed that D-tagatose production was thermodynamically limited in cell-free lysates and transport-limited during whole-cell catalysis. Next, we focused on improving productivity through an investigation and subsequent mitigation of membrane transport barriers. We explored, in detail, cellular engineering strategies including surface display, overexpression of native and non-native sugar transporters, and cell permeabilization techniques to achieve a superior whole-cell biocatalyst for D-tagatose production compared to those reported in literature. Through this investigation, were able to circumvent the thermodynamic conversion barrier while maintaining high reaction rates. This work provides novel insights and demonstrates new tools to guide engineering efforts in probiotic Lactobacillus plantarum as well as other gram-positive bacteria. Additionally, this works also demonstrates how to balance thermodynamic and kinetic limitations in biocatalysis.