Differences in the properties of extracellular polymeric substances responsible for PAH degradation isolated from Mycobacterium gilvum SN12 grown on pyrene and benzo[a]pyrene

Abstract

To evaluate the differences in the characteristics of extracellular polymeric substances (EPS) secreted by Mycobacterium gilvum SN12 (M.g. SN12) cultured on pyrene (Pyr) and benzo[a]pyrene (BaP) , heating method was used to extract EPS from M.g. SN12, and the composition, emulsifying activity and morphology of EPS extracts were investigated in this study. It was indicated that EPS extracts varied significantly with the addition of Pyr or BaP to the bacterial cultures. Concentration of proteins and carbohydrates, the main components of the EPS extracts, rst increased and then decreased, with an increase in the concentration of Pyr (0-120 mg L -1 ) and BaP (0-120 mg L -1 ). A similar trend was observed for the emulsifying activity of the EPS extracts. EPS extracted from all cultures exhibited a compact structure with smooth surface, except EPS extracted from BaP-grown M.g. SN12, which exhibited a more fragile and softer surface. These ndings suggest that Pyr and BaP had different in uence on the properties of isolated EPS, providing insights into the mechanism underlying PAH biodegradation by some bacteria secreting EPS. To the best of our knowledge, this is the rst report on the texture pro le of EPS samples extracted from M.g. SN12 grown on PAHs.