Screening and evaluation of novel yeasts for biosurfactant production from the palm oil mill effluent

The present study reports the isolation, screening and characterization of diverse yeast strains from different geographical regions for the valorization of waste palm oil mill effluent (POME) for biosurfactant production. A total of 192 yeast strains were isolated from different samples and screened for biosurfactant production, among which 57 yeasts demonstrated biosurfactant activity on POME via the drop-collapse method. The highest proportion of positive isolates (9.3%) were sourced from West Java, followed by Bali, West Sumatra, and East Kalimantan, each contributing 2.6% of the total biosurfactant-producing yeasts. Principal component analysis (PCA) revealed predominance of Trichosporon and Candida strains in the samples collected from Bali and Central Java, while Pichia and Rhodotorula dominated yeasts from West Java and Sulawesi. Genus-level analyses revealed Candida and Pichia as the most-promising genera contributing 60% of the total biosurfactant-producing yeasts. The secondary screening by emulsification of olive-oil revealed 21% of yeast strains with significant biosurfactant-production potential, highlighting the highest emulsification indices (EI ₂₄ ) of 51.2%, 43.6%, and 21.1% of Pichia pinus Y125, Candida quercitrusa Y359 and Pichia sp. Y158 respectively. The optimal pH and substrate concentration for maximum production of biosurfactants were pH 7.0 and 20% POME, respectively. Fourier transform infrared spectroscopy (FTIR), and gas chromatography-mass spectrometry (GC-MS) analyses further confirmed the composition of biosurfactants synthesized by P. pinus Y125 and C. quercitrusa Y359 at 20% POME and pH 7.0. This study provides the first report of biosurfactant production by P. pinus Y125 and C. quercitrusa Y359 utilizing POME waste, underscoring the feasibility of waste valorization through microbial bioprocessing. Furthermore, the above findings underscore the promising potential of diverse environmental yeasts, notably P. pinus Y125 and C. quercitrusa Y359, for the production of biosurfactants from waste POME that might find potential applications in bioremediation and food industry.

The online version contains supplementary material available at 10.1007/s13205-026-04850-8.