Investigating the role of mechanics in lignocellulosic biomass degradation during hydrolysis.

Enzymes and mechanics play major roles in lignocellulosic biomass deconstruction in biorefineries by catalysing chemical cleavage or inducing physical breakdown of biomass, respectively. At industrially relevant substrate concentrations mechanical agitation is also a driving force for mass transfer as well as agglomeration of elongated biomass particles. On the contrary to the physically induced particle attrition, which typically facilitates feedstock handling, particle agglomeration tends to hinder mass transfer and in the worst case induces processing difficulties like pipe blockage. Understanding the complex interplay between mechanical agitation and enzymatic degradation during hydrolysis is therefore critical and was the aim of this study. Particle size analyses revealed that neither mechanical agitation alone nor enzymatic treatment without mechanical agitation had any noteworthy effect on flax fibre attrition. Similarly, successive treatment, where mechanical agitation was either preceded or proceeded by enzymatic hydrolysis, did not induce any substantial segmentation of flax fibres. Simultaneous enzymatic and mechanical treatment on the other hand was found to promote fast fibre shortening. Higher hydrolysis yields, however, were obtained from non-agitated samples after prolonged enzymatic treatment, indicating that mechanical agitation in the long run reduces activity of the cellulolytic enzymes. This article is protected by copyright. All rights reserved.