Nonsterile l-Lysine Fermentation Using Engineered Phosphite-Grown Corynebacterium glutamicum

Abstract

Fermentation using Corynebacterium glutamicum is an important method for the industrial production of amino acids. However, conventional fermentation processes using C. glutamicum are susceptible to microbial contamination and therefore require equipment sterilization or antibiotic dosing. To establish a more robust fermentation process, l -lysine-producing C. glutamicum was engineered to efficiently utilize xenobiotic phosphite (Pt) by optimizing the expression of Pt dehydrogenase in the exeR genome locus. This ability provided C. glutamicum with a competitive advantage over common contaminating microbes when grown on media containing Pt as a phosphorus source instead of phosphate. As a result, the engineered strain could produce 41.00 g/L l -lysine under nonsterile conditions during batch fermentation for 60 h, whereas the original strain required 72 h to produce 40.78 g/L l -lysine under sterile conditions. Therefore, the recombinant strain can efficiently produce l -lysine under nonsterilized conditions with unaffected production efficiency. Although this anticontamination strategy has been previously reported for other species, this is the first time it has been demonstrated in C. glutamicum ; these findings should aid in the further development of cost-efficient amino acid fermentation processes.

Physiological changes and growth behavior of Corynebacterium glutamicum cells in biofilm

“…Previously, we deleted exeM and exeM1 in a L-proline-producing strain which promoted biofilm formation ( Ren et al, 2020 ). We also constructed an exeR (the homolog of exeM and exeM1 ) deletion mutant in an L-lysine-producing strain Cg-0206 ( Lei et al, 2021 ), but it had litter effects on biofilm formation. Here, both the wild-type model strain C. glutamicum ATCC13032 and the industrial strain Cg-0206 were studied.…”

Metabolic Engineering for Valorization of Agri- and Aqua-Culture Sidestreams for Production of Nitrogenous Compounds by Corynebacterium glutamicum

“…Phosphite (also name phosphonate), which is used as organic fertilizer and is non-toxic to humans and animals, does not support growth of C. glutamicum as source of phosphorus. Transfer of phosphite dehydrogenase from Pseudomonas stutzeri to a lysine producing C. glutamicum strain enabled growth in non-autoclaved growth medium that contained phosphite instead of phosphate ( Lei et al, 2021 ). While lysine was produced under non-sterile conditions, this approach can only be applied at larger scale using sidestreams from aqua- and agriculture that lack phosphate or require addition of a phosphorus source.…”

Metabolic Engineering of Corynebacterium glutamicum for Sustainable Production of the Aromatic Dicarboxylic Acid Dipicolinic Acid

“…Sterilization is money-, time-and resource-consuming [72,73]. Non-sterile contamination-free fermentation processes are important [74] and have been realized for B. subtilis, E. coli, and C. glutamicum [72,73,75]. The use of phosphite instead of phosphate combined with expression of the phosphite dehydrogenase gene ptxD from Pseudomonas stutzeri allowed non-sterile production of L-lysine by C. glutamicum [72,75].…”