Production of a microbial emulsifier with biotechnological potential for environmental applications

The present work reports the production of bioemulsifiers (BEs) by an environmental bacterium closely related to Bacillus spp., using agro-industrial wastes and by-products as low-cost carbon sources. Maximum emulsifying activity was detected using crude glycerol (CG) (E₂₄ = 59%), producing 2.8 g/L of BE at 24 h of incubation. The microbial product presented significantly higher biodegradability in comparison to three commercial emulsifying agents (sodium dodecyl sulfate, SDS; Tween 80; and Arabic gum, AG). Interestingly, BE proved to be innocuous for Caco-2 cells and wheat seedlings, used as toxicological indicators. The BE and AG showed (in most of the cases) higher stability to changes in temperature (37 °C-100 °C), pH (3-10), and salt concentration (5% and 10%, w/v) in comparison to the SDS and Tween 80. Finally, the microbial product displayed a large affinity to a wide range of hydrophobic substrates showing emulsifying activities similar to or even better than SDS, Tween 80 and AG. The results presented in this study demonstrate the potential of a bioproduct obtained from CG to be used for environmental purposes.