# Identification and functional characterization of a potential l-Homoserine exporter in Corynebacterium glutamicum

## TL;DR

Researchers identified a new protein in bacteria that helps export l-Homoserine, improving its production and tolerance.

## Contribution

A novel l-Homoserine exporter, Cg0701, was identified and characterized in Corynebacterium glutamicum.

## Key findings

- Overexpression of Cg0701 increased cell growth by 10.45% in the presence of l-Homoserine.
- l-Homoserine export capacity increased by approximately 30% in the overexpression strain.
- Recombinant strain CgH-11 achieved 48.72 g/L l-Homoserine production in a 5 L fermenter.

## Abstract

•A novel l-Homoserine exporter was identified in C. glutamicum.•The exporter significantly enhances l-Homoserine tolerance and export capacity.•The exporter greatly increases l-Homoserine production.

A novel l-Homoserine exporter was identified in C. glutamicum.

The exporter significantly enhances l-Homoserine tolerance and export capacity.

The exporter greatly increases l-Homoserine production.

Exporter protein systems play a crucial role in the efficient production of valuable chemicals. However, the lack of active exporters significantly limits the application of industrial bio-based production, making the identification and utilization of novel exporters highly important. In this study, we discovered a novel l-Homoserine exporter, Cg0701, in Corynebacterium glutamicum through homology analysis. First, tolerance assays revealed that the cg0701 overexpression strain (CgH-2) exhibited a 10.45% increase in cell growth compared to the control when cultivated with 30 g/L-Homoserine. Additionally, export assays demonstrated that the l-Homoserine export capacity of CgH-2 increased by approximately 30%. Furthermore, genomic overexpression of cg0701 in an l-Homoserine-producing chassis also enhanced both tolerance and export activity. As a result, the recombinant strain CgH-11 produced 10.79 g/L-Homoserine in shake flask cultures and 48.72 g/L in a 5 L fermenter, representing improvements of 19.89% and 24.44%, respectively. In summary, our results indicate that Cg0701 is a novel l-Homoserine exporter in C. glutamicum, enriching our understanding of amino acid export systems and providing a valuable target for the construction of l-Homoserine microbial cell factories.

Image, graphical abstract