Fig. 1

Isolation of FA degrading bacteria. A Growth of eight isolates on M9-FA agar plates at 28 °C for 48 h. B Degradation of FA to PA by isolates cultured in M9-FA medium at 28 °C for 48 h. Filled bars, FA; unfilled bars, PA. Error bars, standard errors of means (n = 3, p < 0.05). *P < 0.05 (control FA vs. accumulated PA). C Nucleotide sequences of selected strains were aligned, and phylogenetic trees were constructed by neighbor-joining method [33] using MEGA X software [34]. Numbers along branches indicate 1000 bootstrap replicates D Time-dependent decomposition of FA by typical culture of Variovorax sp. F1 in M9-FA medium at 28 °C for 48 h. ●, FA; ■, PA; ▲, DFA; ◆, DPA. Bars, cell growth estimated as total cellular proteins. Error bars, standard errors of means (n = 3). DFA, deaminofolic acid; DPA, deaminopteroic acid; FA, folic acid; PA, pteroic acid