Antifungal Activity of Pyocyanin like Compound of Pseudomonas aeruginosa JT25 Isolated from Gloriosa superba L.

Abstract

Isolation of rhizobacteria from the rhizosphere of medicinal plants for screening antimicrobial compounds has paved an alternate way for a sustainable approach to agriculture. In our investigation, 109 isolates were obtained from the rhizosphere of Gloriosa superba L., commonly known as glory lily and screened for their antagonism against 6 test fungal pathogens. Three isolates showed promising antibiosis and were further screened for bioactive metabolite production. The present study was limited to the evaluation of antimicrobial properties of one of the isolates Pseudomonas aeruginosa JT25 and optimization of biomass production and antimetabolite yield based on different cultural parameters such as pH, temperature, incubation period along with the effect of various carbon and nitrogen sources. JT 25 showed maximum biomass production at a pH of 7. In contrast, bioactive metabolite production was maximum at a pH of 8.5 on the 5th day of incubation at 35?C, using glycerol and peptone as C and N sources, respectively. The antimicrobial compound was extracted with chloroform and purified with column chromatography and thin-layer chromatography (TLC). Using chloroform, dichloromethane, and methanol in the ratio of 8:1:1, two active compounds were isolated through TLC with Rf values 0.73 (blue) and 0.90 (yellow), respectively. The blue pigment?s minimum inhibition concentration was recorded as 0.5 mg/mL against Rhizoctonia oryzae sativa and highest against Alternaria solani. The yellow pigment did not show significant antibiosis.. KEYWORDS :Antimicrobial, Fungal pathogens, Gloriosa superba, Medicinal plants, Pseudomonas, Rhizobacteria