Characterization and antifungal activity of the yellow pigment produced by a Bacillus sp. DBS4 isolated from the lichen Dirinaria agealita

This study emphasis the production of yellow pigment from endolichenic Bacillus sp. isolated from the lichen Dirinaria aegialita (Afzel. ex Ach.) B.J. Moore. Yellow pigment-producing twenty different strains were investigated. The hyperactive pigment-producing bacterial strain was identified as Bacillus gibsonii based on 99 % sequence similarity. Maximum bacterial pigment production appeared in Luria Bertani medium. Methanol extraction of the pigment and its partial purification using TLC was carried out. Furthermore, isolated pigments were characterized using UV-visible spectroscopy, FTIR spectroscopy, and GC-MS results related to the possibility of the carotenoid occurrence. The pigment also exhibited efficient antifungal activity against selected fungal pathogens of economic importance. Likewise, the pigment extract evaluated for the total antioxidant potential using Phosphomolybdenum and Ferric reducing antioxidant power assay and the results represented in Ascorbic Acid Equivalent (AAE)- 21.45 ± 1.212 mg/mL. The SC50 of the pigment extract found to be 75.125 ± 0.18 µg/ml determined by the ABTS assay. Keywords: Pigment, Lichens, Bacillus sp., Antifungal activity, FTIR, GC-MS