Media Optimization and Partial Purification of Anti-Candida Compound of Probiotics Cultures

Abstract

Fungal infections in humans are mostly due to Candida albicans, an opportunistic commensal yeast that causes systemic and invasive candidiasis. Conventional treatment of candidiasis using antifungal compounds such as polyenes and azoles can cause various side effects. Besides, treatment becomes difficult as the organism acquires resistance. Probiotics with anti-candida activity have been projected as a safe and alternative solutions to treat candidiasis. Probiotic Bacillus isolates previously reported showed wonderful activity against pathogenic Candida species. This study reports on media optimization and partial purification of anti-candida compounds from probiotic Bacillus isolates MW3, MW9, MW19, and MW27. Maximum growth and anti-candida activity (2.9 cm inhibition zone) by the isolate culture was observed when media had been optimized with dextrose, casein and peptone. The media composition numbers 18, 4 and 19 showed the best growth for MW3, MW9, MW19 and MW27. Fractions obtained by solvent precipitation using acetone and methanol showed activity against the pathogen, and the fractions were further purified by ultra-filtration. After ultra-filtration, it was found that the size of the active compound was between 10 to 30 kDa. The compound lost its activity after treatment with proteinase K.