Challenges and possibilities with high solids lignocellulose fermentation
Tuesday, April 29, 2014: 9:45 AM
Grand Ballroom A-C, lobby level (Hilton Clearwater Beach)
Rakesh Koppram1, Ruifei Wang2, Eva Albers2, Carl Johan Franzen2, Charis Xiros2, Elia Tomas-Pejo2 and Lisbeth Olsson1, (1)Chemical and Biological Engineering - Industrial Biotechnology, Chalmers University of Technology, Gothenburg, Sweden, (2)Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
One current research trend in lignocellulose based ethanol production  is to increase the solid substrate loading in order to increment the final ethanol concentration, leading to decreased distillation costs and improved water economy. Even though several challenges have to be addressed, this is an important research direction with broad implications towards development of lignocellulose based biorefineries.

 Firstly, at high solids loading of typically 15-30 (w/w) %, high viscosity prevail leading to poor mixing and therefore large deviation in local conditions in the fermentor. The high solid content may also have a direct influence on the enzymes and microorganisms. Secondly, high concentrations of inhibitory  compounds will typically  be present leading to poor cellular performance and cell viability problems. In our research group we address these problems both by developing the fermentation strategies and through strain improvement. In this presentation, insights from physiological behavior at high solids condition will be discussed in light of designing fermentation strategies suitable for high solid conditions. To tackle the cell viability problems at high solids, evolutionary engineering was applied to improve the cellular performance.  Furthermore, studies for increasing the understanding of the importance of cell propagation for fermentation performance were pursued.