Aqueous two-phase systems for extractive enzymatic hydrolysis of biomass

Sugars derived from lignocellulosic materials are the main carbon sources in bio-based processes aiming to produce renewable fuels and chemicals. One of the major drawbacks during enzymatic hydrolysis of lignocellulosic materials to obtainsugars is the inhibition of enzymes by reaction products (cellobiose and glucose).

This effect is even more pronounced in hydrolysis containing high solid content (15-20% or higher water-insoluble solids – WIS), which is desired in order to obtain hydrolysates containing high total reducing sugar concentration and reduced water usage1. The aim of this project is to develop a new process for sugarcane bagasse hydrolysis using aqueous two-phase system.

This system will be applied as in situ extraction aiming to remove the reaction products as they are released. As a consequence of product removal, enzymes tend to maintain their maximum activity2. The phase-components of the systems will be chosen taking into account their costs, viscosity, capacity of regeneration, melting point, solubility and partition of sugars and proteins.

The pre-selected components will be studied and tested in high-throughput experiments3, in order to determine their partition coefficients of sugars and enzymes, phase diagrams and volumetric ratios. The results of this project will make possible to design a process that enables high sugar concentration during the hydrolysis reaction, overcoming one of the biggest drawbacks regarding the production of second-generation ethanol: the enzymatic inhibition.

The achievement of the project’s goal can lead to, but not limited to, three consequences: enhancement of sugarcane mills productivity; reduction of fossil fuels usage, which can accelerate the energetic independence in many countries; and contribution to a more sustainable economy. This paper will present optimal aqueous two-phase systems for the separation of sugars and enzymes, which allow the development of an improved second-generation ethanol process.