Isolation, screening and molecular characterization of biosurfactant producing yeasts with antibiofilm potential

Project no. 23404 · Status: Kapanmış (Yayın bekleniyor) · 2022

Summary

Surfactants are surface-active substances that can reduce surface and interfacial tension by accumulating between two phases due to their hydrophobic tail and hydrophilic head group. Since microbial biotransformation of complex synthetic surfactants is difficult, the accumulation of these pollutants in the environment causes toxicity in living systems. Biosurfactants are molecules produced by microorganisms that have functions similar to those of synthetic surfactants. Studies on biosurfactants and their industrial use are increasing due to their advantages, such as susceptibility to biodegradation, low toxicity, and chemical diversity. Biological activities such as antibiofilm, antimicrobial, and antiviral activity also indicate its potential for medical applications. The market for biosurfactants, which exceeded $1.5 billion in 2019, is estimated to reach $2.5 billion between 2020-2026. All these data emphasize the necessity of investigating new biosurfactants of microbial origin.In this study, 48 biosurfactant-producing yeasts with antibiofilm potential were isolated from soil samples contaminated with petroleum derivatives. The biosurfactant production potential of yeasts was determined by screening tests, including oil displacement assay, drop collapse assay, parafilm M test, hemolysis test, CTAB agar test, and calculation of emulsification indexes (E24). The D1/D2 domains of the 26S rDNA regions of the yeast strains with the best results were amplified by PCR, and molecular identification was performed through sequence analysis. The strains with the highest capacity to reduce surface tension were determined as Candida parapsilosis BPY-Y45 (33.33±0.29 mN m-1) and Nakaseomyces glabratus BPY-Y6 (33.5±0.5 mN m-1). The biosurfactant obtained from Candida parapsilosis BPY-Y45 strain was partially purified, and its antibiofilm activity on biofilms produced by Salmonella typhmurium and Salmonella epididymitis was examined by crystal violet method and scanning electron microscopy. Depending on the increasing concentration (12%, 25%, and 50%) of the partially purified biosurfactant, 60.14%, 72.61%, and 89.87% antibiofilm activity against Salmonella typhimurium biofilm was determined. Similarly, 87%, 94%, and 95% antibiofilm activity against Salmonella epididymitis biofilm was determined using the same biosurfactant concentration. Deformations in the biofilm structure observed using scanning electron microscopy also supported the data obtained. The detected antibiofilm activity of the biosurfactant produced by Candida parapsilosis BPY-Y45 strain offers an potential environmentally friendly alternative to combat biofilms formed by different Salmonella species.

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