BIOSURFACTANT PRODUCTION BY YEASTS ISOLATED FROM THE BRAZILIAN ECOSYSTEM

Biosurfactants are amphiphilic molecules produced by microorganisms that exhibit high biodegradability, low toxicity, and stability under different temperature, pH, and salinity conditions, making them a sustainable alternative to synthetic surfactants. However, their industrial-scale application is still limited by high production costs. In this context, this study aimed to evaluate biosurfactant production by the yeast Papiliotrema terrestris (UFMG–LLY6.4) in a bench-scale bioreactor under different cultivation conditions. Initially, P. terrestris was cultivated in Erlenmeyer flasks containing a medium composed of xylose (40 g/L), soybean oil (10%), peptone (6 g/L), and yeast extract (3 g/L). After the selection stage, the yeast was cultivated in a bench-scale bioreactor. Reactor R2 was operated by maintaining dissolved oxygen at 30% and a yeast extract concentration of 5 g/L. Cell growth was monitored over 120 hours by optical density (OD), using an OD-tobiomass correlation curve to estimate cell concentration. Biosurfactant production was evaluated by the emulsification index (E24) after 48 and 120 hours of cultivation. Reactor R2 showed progressive cell growth throughout the cultivation, with an estimated biomass concentration reaching 5.86 g/L after 120 hours. In the emulsification assays, E24 values of 31.31 ± 4.03% after 48 hours and 70.98 ± 6.3% after 120 hours were obtained, demonstrating greater emulsifying activity at the end of the cultivation. The results demonstrate that Papiliotrema terrestris has potential for biosurfactant production, particularly under condition R2, which yielded a biomass concentration of 5.86 g/L and an emulsification index of 70.98 ± 6.3% after 120 hours of cultivation in a bench-scale bioreactor. These findings highlight the yeast’s ability to produce compounds with emulsifying activity under the conditions evaluated and provide a basis for further studies on culture condition optimization and process scale-up.

Acknowledgments: The authors thank FAPEMIG, CAPES, CNPq, UFSJ, and CNPEM for their financial support and infrastructure.