Biorefining of Bark in Biochemical Conversion and in Forest-Industrial Processes

Bark is an underutilized residual stream from pulp and saw mills and its utilization in biochemical conversion is not well investigated.

The project will address the technical and economic potential of separate biorefining of fresh bark through innovative pre-processing technology and green extraction. The project covers the predominant bark varieties in Sweden, i.e., bark from spruce, pine and birch.

Preliminary experiments indicate that high extraction yields can be obtained and with that also new products, such as bark-based fatty and resin acids and polyphenols.

In biochemical conversion, debarking is not necessarily a part of the process, and separate biorefining of bark through green extraction will be weighed against the common approach to include wood and bark mixtures in pre-treatment and saccharification steps.

Better use of bark has potential to provide more liquid biofuel without increased withdrawal of forest resources, new products, and improved biochemical conversion.