Global challenges encountered today within energy sector are attributable to increasing emissions of green house gases in parallel with the worldwide growing demand for energy. Replacement of fossil raw materials by renewable ones would provide at least one feasible solution for relieving the problem. Within the transport sector, the use of bioethanol as fuel is increasing. However, so far bioethanol has predominantly been produced by 1st generation technology from sugar cane or starch derived from maize. In Europe instead of sugar cane, grain and sugar beet have been favoured as raw materials. 2nd generation biofuels would be much more energy efficient and contribute significantly more to reduced CO2 emissions.
Production of 2nd generation biofuels is generally based on lignocellulosic biomass originating from agricultural and forestry wastes and energy crops. For degrading pretreated lignocellulosic raw materials to fermentable sugars, novel tailormade enzyme systems would be needed. Enzymatic hydrolysis of biomass is known to provide higher yields of sugars under mild reaction conditions than the traditional chemical hydrolysis with strong acids.
Besides easily fermentable hexoses (C6 sugars), a significant portion (15-40%) of sugars in lignocellulosic biomasses consists of pentoses (C5 sugars). Yeast and bacterial strains capable of fermenting C5 sugars (e.g. xylose, arabinose) have recently been developed. However, for facilitating economically feasible biofuel production, more robust strains with increased rate of pentose fermentation should be developed.
Main NEMO objectives
The project seeks technologies with highest impact on bioethanol production and will focus on
1) Development of high-performance enzymes and enzyme mixtures for efficient hydrolysis of lignocellulosic raw materials of European interest
2) Generation of stress tolerant yeasts for efficient fermentation of C6 and C5 sugars derived from lignocellulosic materials to ethanol
NEMO Work Packages
WP 1. Raw materials
WP 2. Efficient novel enzymes
WP 3. Optimized enzyme mixtures
WP 4. New strains through mutagenesis
WP 5. Targeted strain engineering
WP 6. Process assessment
WP 6 is designed to provide information to WPs 1-5 and supply data for process economic calculations for WP 7. The improved enzymes, microorganism and processes will be compared to the baseline conditions. Novel process regimes (temperature, feeding strategies, etc) for improved yield and productivity will also be generated. The best enzyme, microorganism and process combinations identified will be evaluated at pilot scale.
WP 7. Process calculations