Environmental Impacts of Biosurfactant Production Based on Substrates from the Sugar Industry
Andreas Schonhoff, Nina Ihling, Andrea Schreiber, Petra Zapp
Abstract
Regarding the omnipresent issue of climate change, establishing a bioeconomy appears reasonable but requires critical analysis of its products. This project-specific study (project Bio2) presents previously unknown environmental impacts caused by the novel production of biosurfactants (rhamnolipids (RLs) and mannosylerythritol lipids (MELs)) based on substrates from the sugar industry (molasses and sugar beet pulp) using life cycle assessment (LCA). The identification of critical impacts and processes (e.g., extraction agent production) reveals optimization potentials for the considered forward-looking process designs. Based on surfactants’ specific cleaning performance, environmental impacts vary substantially for RLs and MELs. The primary causes of MEL productions’ lower environmental impacts are advantageous microbial properties and process designs. Substrate choice does not play an essential role. An analysis of realistic yield changes and comparisons with conventional surfactants sharpens the view on the development position of the chosen surfactants. In particular, MELs show environmental benefits compared to today’s oleo-/petrochemical-produced surfactants. Identified optimization options (e.g., increased agent recycling) and yield increases could strengthen especially the advantages of MELs. In summary, the results show advantages of MELs compared to RLs to some degree, indicate weak points of current processes, and highlight favorable options for the future design of RL and MEL production in terms of their environmental impact.