Multi-omics analyses of evolved Corynebacterium glutamicum mutants reveal the molecular responses to formaldehyde stress.

Formaldehyde serves as a crucial intermediate metabolite during C1 compounds biotransformation. To optimize C1 utilization efficiency, it is essential to identify genes related to formaldehyde tolerance and enhance microbial resistance. Hence, we developed an evolved Corynebacterium glutamicum strain, FM-3, capable of withstanding 2.6 mM formaldehyde-a significant improvement over the parental strain. Integrated transcriptomic and proteomic analyses revealed that the enhanced formaldehyde tolerance correlated with the upregulation of cell wall biosynthesis proteins and DNA repair machinery. Genetic mutations identified in the evolved strains indicated that mutations in Cgl1199 (transcription termination factor Rho), and Cgl1590 (putative gluconeogenesis factor) played a pivotal role in formaldehyde tolerance. Further studies showed that Cgl1590 was involved in cell morphology regulation. This study enriches the understanding of formaldehyde tolerance mechanisms in C. glutamicum and provides guidance for enhancing strain tolerance to formaldehyde.