Production of exopolysaccharides with a high emulsifying activity using an Idiomarina strain under different conditions of oxygen transfer and temperature

Background: Marine microbial exopolysaccharides are the most significant group of polymeric material biopolymers on earth; they exhibit many potential applications in industrial, medical, and environmental fields, due to their chemical structure, which determines their functional properties. This study aimed to evaluate the production and the emulsifying activity of the exopolysaccharides produced by Idiomarina sp. B7H2 cultured under different oxygen transfer rates (OTR) and incubation temperatures. Results: In cultures developed at low incubation temperatures (15 degrees C), an increase in OTRmax from 4.2 to 8 mmol L-1 h(-1) promoted cellular growth and exopolysaccharide production, reaching a dry weight biomass of 7.7 +/- 0.03 g L-1 and a maximal exopolysaccharide production of 4.28 +/- 0.14 g L-1. In contrast, at high incubation temperature (25 degrees C) and at high OTRmax of 8 mmol L-1 h(-1), a maximal emulsifying activity of 75.5% was obtained. This value was higher with respect to that obtained at the lower OTRmax (4.2 mmol L-1 h(-1)). However, higher emulsifying activity was not related to the synthesis of exopolysaccharides. Conclusion: Overall, our results indicate that by controlling the OTRmax and incubation temperatures it is possible to manipulate the production and the emulsifying activity of the bacterial exopolysaccharide produced by B7H2 strain, mainly carrying out the fermentation process at high incubation temperatures and higher OTRmax. (c) 2023 Society of Chemical Industry (SCI).