Abstract:The overexpression of trehalose synthase in the L-glutamate producer Corynebacterium glutamicum was studied. The constitutive expression plasmid was used for overexpression of trehalose synthase in Lglutamate producing C. glutamicum CICC20935 and the recombinant strain 20935T was obtained. The strain 20935T displayed a flocculation phenotype and increased the L-glutamate production by 70% in the medium with glucose as the sole carbon source. The results of ultrathin section transmission electron microscopy revealed that the integrality of trehalose-containing outer membrane mycomembrane of the cell wall of strain 20935T was decreased. Addition of maltose in the culture process of strain 20935T suppressed the conversion of trehalose to maltose by trehalose synthase，and the cells did not display the flocculation phenotype，with the L-glutamate production decreasing by 34%-48%. Overexpression of trehalose synthase in C. glutamicum could affect cell wall integrity and L-glutamate production.