Anti-Candida effect of bacillomycin D-like lipopeptides from Bacillus subtilis B38

Bacillus subtilis B38, isolated from soil, showed antimicrobial activity against human pathogenic Candida albicans species. Specific PCR primers revealed the presence of the bamC gene, which is involved in the biosynthesis of bacillomycin D. Three anti-Candida compounds designated a(1), a(2) and a(3) were purified from culture supernatant and identified using matrix-assisted laser desorption/ionization time-of-flight MS as analogues of bacillomycin D-like lipopeptides of 14, 15 and 16 carbon fatty acid long chains, respectively. The compound a(3) displayed the strongest fungicidal activity against pathogenic C. albicans strains. It was even more active than amphotericin B with a lethal concentration of 59.07 vs. 135.26 mu M of the antimycotic drug against the pathogenic strain C. albicans sp. 311 isolated from finger nail. Only moderate or weak anti-Candida activity was recorded for a(1) and a(2) compounds. Furthermore, a(3) showed the highest hemolytic activity, reaching 50% hemolysis at 22.14 mu M, whereas a(1) and a(2) displayed a limited hemolysis at 68.26 and 37.41 mu M, respectively. These findings suggest that the acyl chain length of bacillomycin D-like lipopeptides plays a major role in hemolytic and antifungal activities.