Adjacent-possible ecological niche: growth of Lactobacillus species co-cultured with Escherichia coli in a synthetic minimal medium

• Published in: Scientific reports 2017-10, Vol.7 (1), p.12880-9, Article 12880
• Main Authors: Mizuno, Kouhei, Mizuno, Mamiko, Yamauchi, Mio, Takemura, Aya J., Medrano Romero, Veronica, Morikawa, Kazuya
• Format: Article
• Language: English
• Subjects: 631/326/2565/855; 692/4020/2741/2135; Auxotrophs; Cell culture; Coculture Techniques; Culture Media - pharmacology; E coli; Ecosystem; Escherichia coli; Escherichia coli - cytology; Escherichia coli - drug effects; Escherichia coli - growth & development; Humanities and Social Sciences; Lacticaseibacillus casei - drug effects; Lacticaseibacillus casei - growth & development; Lactobacillus; multidisciplinary; Science; Science (multidisciplinary); Species; Staphylococcus aureus - drug effects; Yogurt
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-12894-3

In certain conditions, members of the Lactobacillus genus are auxotrophs that have fastidious requirements for growth. Notably, Lactobacillus cannot grow in M9 medium, a minimal synthetic medium used for Escherichia coli . However, we found that some Lactobacillus strains can be grown in M9 when co-cultured with E. coli K-12. In the co-culture, L. casei proliferates exponentially, reaching cell densities of 10 8 CFU (colony-forming unit) ml −1 in 6 h and dominating E. coli in the late growth phase. Spent medium from E. coli grown overnight lacked this growth-promoting effect on L. casei . Similarly, the effect was not observed when the species were separated by a 0.4-µm membrane. Microscopic observations showed that L. casei are embedded in the micro-scale clusters of E. coli in the early growth phase. This study describes for the first time the ability of a Lactobacillus species to grow in minimal medium when in close proximity with co-cultured bacteria.