FIG 4.

Biosynthesis of vitamin B₁₂ by strain A. muciniphila strain CSUN-17, as confirmed by bioassays using L. leichmannii ATCC 7830 (A) and mutant strains of E. coli (B). Growth of L. leichmannii strain ATCC 7830, an E. coli ΔmetE strain, and an E. coli ΔmetE ΔmetH strain was measured in growth medium with and without vitamin B₁₂ supplementation and with cell lysates from both A. muciniphila Muc^T and A. muciniphila strain CSUN-17. Growth was measured as OD₆₀₀. Values were averaged from three biological replicates, and error bars represent the standard deviations.