Complex media are routinely used to cultivate diverse bacteria. However, this complexity can obscure the factors that govern cell growth. While studying protein acetylation in buffered tryptone broth supplemented with glucose (TB7- glucose), we observed that Escherichia coli did not fully consume glucose prior to stationary phase. However, when we supplemented this medium with magnesium, the glucose was completely consumed during exponential growth, with concomitant increases in cell number and biomass but reduced cell size. Similar results were observed with other sugars and other peptide-based media, including lysogeny broth. Magnesium also limited cell growth for Vibrio fischeri and Bacillus subtilis in TB7- glucose. Finally, magnesium supplementation reduced protein acetylation. Based on these results, we conclude that growth in peptide-based media is magnesium limited. We further conclude that magnesium supplementation can be used to tune protein acetylation without genetic manipulation. These results have the potential to reduce potentially deleterious acetylated isoforms of recombinant proteins without negatively affecting cell growth.
- Complex media
- Improved cell growth
ASJC Scopus subject areas
- Food Science
- Applied Microbiology and Biotechnology