EnXylaScope: Environmental implications of an innovative enzyme-based process for the production of xylan products

D7.3

Authors: Maximilian Breyer, Heiko Keller, Sven Gärtner, Nils Rettenmaier

A novel lignocellulose biorefinery concept following a so-called xylan-first approach was developed in the EU-funded project EnXylaScope. Enzyme-assisted alkali extraction designed for wet biomass was found to be suitable for extracting polymeric to oligomeric decolourised xylan as the main product from several lignocellulosic biomass feedstocks. This xylan can optionally be functionalised by enzymes. The potential for high value use of the extracted xylan has been demonstrated in several tested applications. In addition, the biorefinery concept allows high-value use of the co-products cellulose, which can optionally be enzymatically hydrolysed, and several different lignin fractions. While the fermentability of glucose from hydrolysed cellulose has been shown to be similar to that of pure glucose, the recovered lignin is suitable for fractionation and/or uniformisation/depolymerisation which is increasingly found necessary for most types of lignin in high-value applications.

The project is accompanied by an integrated life cycle sustainability assessment covering environmental, economic and social sustainability aspects using a common set of scenarios based on mass and energy balances from detailed process models representing potential future industrial-scale biorefinery variants. The scenarios comprise the use of modified and unmodified xylan as an ingredient in cosmetics and as a health-improving feed additive for pigs. The co-products glucose and lignin are valorised, too. 

This report by IFEU covers the environmental assessment. It assesses the potential environmental impacts that can be associated with the future implementation of the biorefinery concept and derives recommendations for their improvement.