Transcription factor based whole-cell biosensor for inosinic acid in Corynebacterium stationis

IMP(Inosinic acid) is a raw material with extremely important uses in food manufacturing and agriculture. In the selection process of IMP producing strains, there has been no tool available to assist in high-throughput screening, which greatly affects the speed of strain development. To address this issue, we have developed a whole cell IMP biosensor based on the characteristics of GlxR, a member of the CRP/FNR transcription factor family in Corynebacterium stationis. By modifying and altering the specificity of GlxR, we transformed the effector molecule from cAMP(Cyclic adenosine monophosphate) to IMP. Our strategies involved optimizing the reporter gene, engineering the GlxR transcription factor via Fluorescence-Activated Cell Sorting (FACS), and manipulating the Pcg3195 promoter. We constructed a synthetic biosensor called pSenIMP-MUT1-Pmmm, which utilized GlxRMUT1, Pcg3195 engineered Pmmm promoters, and EGFP reporter genes. This biosensor facilitated the establishment of a high-throughput screening strategy using FACS. Among the screened cells, 53.33% were identified as the purATTG guaBTTG strain, exhibiting the highest IMP production, while 16.67% were selected as the purATTG strain with the second highest IMP production. Overall, our study presents a novel method for high-throughput screening of IMP producing strains using a synthetic biosensor based on GlxR characteristics. This approach significantly accelerates the strain development process and holds great potential for various industrial applications.