Production of mannosylerythritol lipids from lignocellulose hydrolysates: tolerance thresholds of Moesziomyces antarcticus to inhibitors

Abstract BACKGROUND Moesziomyces antarcticus is an efficient producer of mannosylerythritol lipids (MEL), a biosurfactant with a wide range of potential applications. The use of lignocellulosic biomass can contribute to sustainable MEL production. While lignocellulosic sugars (e.g. D-glucose and D-xylose) can be converted to MEL, the required pretreatment of lignocellulosic biomass releases by-products that are potentially inhibitory for yeasts. A design of experiment (DoE) was performed to evaluate the effect of furfural, acetate and formate on M. antarcticus and their capacity to produce MEL from lignocellulose hydrolysates. RESULTS Furfural presented a higher inhibitory effect on MEL production than the two dissociated weak acids. The DoE was developed for 7-days D-glucose cultures with inhibitors up to 0.7 g L?1 furfural, 2.0 g L?1 acetate and 1.7 g L?1 formate. The model equations relate D-glucose consumption rate and the production of cell biomass, lipids and MEL with the concentration of inhibitors. For example, MEL titre is reduced by 25% when 0.08?g L?1 furfural, 0.29?g L?1 acetate and 0.25?g L?1 formate were used. The model was validated in D-glucose and used to study MEL production in D-glucose and D-glucose/D-xylose mixtures. The use of D-xylose showed a positive effect on MEL production in the presence of inhibitors since similar MEL titres were attained with (0.08?g L?1 furfural, 0.29?g L?1 acetate and 0.30?g L?1 formate) or without inhibitors when using a D-glucose/D-xylose mixture. CONCLUSION This study provides insight to the conditions required by M. antarcticus for MEL production from lignocellulosic hydrolysates and points towards further process and strain development requirements. ? 2018 Society of Chemical Industry