Functional Characterization of Transporters for L-Aspartate in Bacillus licheniformis

Abstract

Amino acid efflux and influx transport systems play vital roles in industrial microorganisms’ cell growth and metabolism. However, although biochemically characterized, most of them remain unknown at the molecular level in Bacillus licheniformis. In this study, three proteins, namely, YdgF, YvbW, and YveA, were predicted to be involved in the active transport of L-aspartate (L-Asp). This was verified by manipulating their encoding genes. When growing in the minimal medium with L-Asp as the only carbon and nitrogen source, the growth of strains lacking proteins YdgF, YvbW, and YveA was significantly inhibited compared with the wild-type strains, while supplementing the expression of the corresponding proteins in the single-gene knockout strains could alleviate the inhibition. Upon overexpression, the recombinant proteins mediated the accumulation of L-aspartate to varying degrees. Compared with the wild-type strains, the single knockout strains of the three protein genes exhibited reduced absorption of L-aspartate. In addition, this study focused on the effects of these three proteins on the absorption of β-alanine, L-glutamate, D-serine, D-alanine, and glycine.

Dual-sgRNA CRISPRa System for Enhanced MK-7 Production and Salmonella Infection Mitigation in Bacillus subtilis natto Applied to Caco-2 Cells

“…Notably, NB205’s MK-7 production was significantly higher than that of B. subtilis 168, positioning it as an optimal candidate for MK-7 synthesis pathway optimization. Although manipulating wild-type strains can be challenging due to a lack of effective genetic tools, successful examples abound in the literature. − Genomic sequencing of NB205 enabled precise genetic engineering with no observed instability issues such as plasmid deletion or overexpression. The isolation of NB205 and its subsequent genomic analysis have provided valuable insights into the genetic manipulation of B. subtilis for enhanced MK-7 production.…”