S50: Application of thermophilic, cellulolytic enzymes and engineered S. cerevisiae strains in an integrated approach for sustainable and cost-effective cellulosic ethanol production

In the past decades, it has become clear that utilization of lignocellulosic biomass is a sustainable and cost-effective option for the production of bioenergy, biofuels and bio-based products. Hydrolysis of the lignocellulosic carbohydrates into fermentable sugars depends on cheap production and application of a number of different (hemi-)cellulases. To be economically efficient, the subsequent cellulosic ethanol production requires not only the consumption of the cellulose-derived glucose, but also the hemicellulose-derived xylose and arabinose.

Within DSM research projects are ongoing, aiming at developing both commercially competitive cellulolytic enzymes for lignocellulose saccharification and genetically engineered yeast strains that ferment hexoses and pentoses to ethanol at high rates and yields. DSM’s enzyme cocktail is uniquely active at high temperature and low pH, offering many benefits and product differentiation. Further strain and process development, enzyme cocktail ratio optimization, protein and genetic engineering have led to significant improvements in productivity and efficiency. Fermentation of hexoses and pentoses in lignocellulosic hydrolysates by DSM’s yeast strains has been accelerated by applying evolutionary engineering strategies. Additionally, next generation advanced yeast strains are under development, aiming at speeding-up the fermentation by optimizing pentose utilization, as well as converting inhibitors and specific biorefinery waste products into additional ethanol.

In this context, it is of great importance to fully integrate the design, construction and operation of a biorefinery for biofuels production. In this presentation, the developments in the aforementioned areas and how those fit within the platform of on-site manufacturing of enzymes and yeast fermentation will be discussed.