Multi-feedstock lignocellulosic biorefineries based on biological processes: An overview

The evolution of lignocellulosic biorefineries increasing the process complexity and integration through the processing of multiple raw biomass-based materials into several products is described. This critical overview deals with available lignocellulosic feedstocks, pretreatment operations, enzymatic saccharification to monosaccharides and their final transformation into bioethanol and other bio-based products. Aspects as process operating conditions, modes of operation, underlying physical and chemical phenomena, and mathematical modelling are addressed. Pretreatment stage is a key step for any further processing, specially when using multifeedstock. The use of ethanol-water mixtures for biomass fractionation is a promising treatment able to compete with the nowadays more employed pretreatment such as steam explotion and diluted acid processes. Enzymatic saccharification of pretreated biomass has been analysed considering its complexity and selectivity. Its mathematical modelling is described in detail, together with the underlying phenomena, highlighting the importance of mass transfer in a biphasic system. An adequate operation unit design, scale-up and control, and process design and integration can be ensured in this way. Finally, biotransformations of monosaccharides to biofuels and platform chemicals is analysed as they are becoming key processes within bioeconomy, in the framework of integrated biorefinery to fuels, chemicals and materials.

Automated summary

The evolution of lignocellulosic biorefineries has increased process complexity and integration by processing multiple raw biomass-based materials into various products. Key steps such as pretreatment and enzymatic saccharification are crucial, with the use of ethanol-water mixtures showing promise as a competitive treatment method.