# Production of the Antimicrobial Roseoflavin With Genetically Engineered Corynebacterium glutamicum

## TL;DR

Scientists engineered a bacteria to produce a promising antimicrobial compound called roseoflavin, achieving the highest production levels in non-native strains.

## Contribution

The highest reported roseoflavin production by a non-native producer using metabolically engineered Corynebacterium glutamicum.

## Key findings

- Overexpression of rosABC and ribM genes improved roseoflavin production in C. glutamicum.
- Thiamine supplementation significantly enhanced biosynthesis of roseoflavin.
- The engineered strain achieved 17.4 ± 1.5 mg/L of roseoflavin, the highest titer in non-native producers.

## Abstract

The global rise of drug‐resistant bacterial infections underscores an urgent demand for novel antimicrobial agents. Roseoflavin, a naturally occurring riboflavin analog, has emerged as a promising candidate for drug development. In this study, the industrial workhorse
Corynebacterium glutamicum
was metabolically engineered towards roseoflavin production. Overexpression of the roseoflavin biosynthetic genes rosABC and the flavin transport gene ribM from the native roseoflavin producer Streptomyces davaonensis was evaluated in
C. glutamicum
. To further link roseoflavin biosynthesis to its riboflavin precursor, the riboflavin kinase gene ribF from both S. davaonensis and
C. glutamicum
was evaluated, revealing that its overexpression is essential for enhancing roseoflavin production. The final engineered strain CgRose6 achieved a roseoflavin titer of 17.4 ± 1.5 mg/L and a volumetric productivity of 0.36 ± 0.03 mg/L·h when cultivated in glucose minimal medium supplemented with thiamine, a relevant coenzyme for roseoflavin biosynthesis. These production values are the highest reported by a non‐native RoF producer to date and demonstrate the feasibility of using
C. glutamicum
as a platform for sustainable roseoflavin production, opening avenues for scalable biosynthesis of this valuable antimicrobial compound.

Corynebacterium glutamicum
was genetically engineered for the production of the riboflavin analog roseoflavin, while minimising its antimicrobial effects. To this end, the genetic machinery from the natural roseoflavin producer Streptomyces davaonensis was evaluated in a riboflavin‐producing
C. glutamicum
strain. Thiamine supplementation in the medium further improved roseoflavin biosynthesis.