Decreasing conversion of biomass. Results collected from several publications indicate that decreasing conversion at increasing solids content is a general effect. Results are for different kinds of biomass and for both enzymatic hydrolysis and simultaneous saccharification and fermentation (SSF). Added trend lines show that for each experiment there is a linear relationships between initial solids content and yield. Data taken from  (enzymatic hydrolysis),  (enzymatic hydrolysis),  (enzymatic hydrolysis),  (SSF),  (enzymatic hydrolysis and SSF) and  (SSF).
Kristensen et al. Biotechnology for Biofuels 2009 2:11 doi:10.1186/1754-6834-2-11