Biosurfactant production by Pleurotus ostreatus in submerged and solid-state fermentation systems

Biosurfactants are surface active molecules that are produced by microorganisms. Their positive features attract the attention of many researchers compared to their chemically synthesized counterparts. This research studied the production of a biosurfactant by Pleurotus ostreatus in submerged fermentation (SmF) and solid-state fermentation (SSF), with and without shaking. Oil spreading efficiency, emulsification index, and surface tension were assessed during the study. The highest emulsification index (E24) values of SmF, SSF with shaking, and SSF without shaking were 60 ± 5.0%, 29 ± 2.5%, and 42 ± 4.0%, respectively, and surface tension values were 40.7 ± 0.9, 30.8 ± 0.8, and 30.6 ± 0.8 mN m^–1, respectively. Based on these data, the produced biosurfactant in SSF with and without shaking was extracted and the amounts were determined as 4.69 ± 0.2 and 4.095 ± 0.2 g L^–1, respectively. In addition to these analyses, chemical composition of the extracted biosurfactant was determined and FT-IR spectroscopy was used to confirm the various functional groups. The obtained results of chemical composition and FT-IR indicated the probability of carbohydrate–peptide–lipid complex features of biosurfactants produced by P. ostreatus.