UPLC-MS analysis of characterization of bioactive compounds produced by endophytic Bacillus tequilensis ALR-2 from Aloe vera plant

Abstract

Endophytic Bacillus tequilensis ALR-2 isolated from Aloe vera plant, was found to have antimicrobial activities attributed to a series of lipopeptide antibiotics and biosurfactants produced. Partial-purification of ethylacetate extracts by column chromatography revealed that fraction SF5 (5mg mL-1) effectively inhibited Bacillus cereus and Staphylococcus aureus (28.6{+/-}0.5 and 30.3{+/-}0.5 mm zone of inhibition, respectively), and was significantly more effective than the standard antibiotics Ciprofloxacin (5g) (23.6 {+/-}0.5 and 18.6 {+/-}0.5 mm, respectively) and Kanamycin (30g) (20.3 {+/-}0.5 and 13.6 {+/-}0.5 mm, respectively). UPLC-MS analysis of SF5 showed three series of ion peaks. The quadrupole-orthogonal ionization time-of-flight mass spectrometer revealed [M+H]+ of 678.4601; 679.4690 and 680.5076 which corresponded to the oligopeptide antibiotic monamycin (mol. wt. 677.84). The [M+H]+ of 1119.8870; 1120.8992 and 1121.9119 corresponded to antibiotic complex 61-26 (mol. wt. 1120.348), a lipopeptide. The third peak of [M+H]+ of 1356.0151 and 1358.0664 could not be classified to existing known compounds in the literatures.