Purification and identification of a new antifungal dipeptide from Bacillus velezensis AR1 culture supernatant.

BACKGROUND

Bacillus velezensis and other Bacillus species are known for the production of bioactive secondary metabolites that are active against plant pathogenic fungi. In view of this, a study was undertaken to investigate the antifungal potential of B. velezensis AR1 culture supernatant.

RESULT: The butanol extract concentrate of B. velezensis AR1 was separated into different fractions by column chromatography. A fraction eluted by 9:1 chloroform: methanol caused 25.8-70.2% and 25.2-56.3% growth inhibition of Monilinia fructicola and Colletotricum goeosporioides, respectively. This fraction was subjected to solid-phase extraction using a Strata SI-1 column and further purified by prep-TLC to obtain a pure metabolite showing a single peak on high performance liquid chromatography. On the basis of the nuclear magnetic resonance (NMR 1 H, 13 C, HH COSY, HSQC and HMBC) analysis, the metabolite was identified as 5-N-tyrosinylornithine. The compound exhibited antifungal activity against two plant pathogenic fungi.

CONCLUSION

5-N-tyrosinylornithine, the secondary metabolite isolated from the culture supernatant of B. velezensis AR1 exhibited significant antifungal activity against two plant pathogenic fungi.