Enzymatic Extraction of Fatty Acids from Bark Residues

Research Project, 2024 – 2027

The forestry industry has significant economic importance globally and at regional levels, especially in North America, and in densely forested Nordic countries like Sweden, Finland and Norway. In spite of having well-developed forestry sectors, a major by-product - bark- remains an underutilized resource, and is still primarily used for low-value applications such as mulching or energy generation.

Bark comprises various components, of which suberin, a complex lipid-like compound,is particularly attractive due to its high fatty-acid content (25 – 50% w/w). In 2021, the global fatty acids market size was valued at USD 20.7 billion, with an annual growthrate of 5.3%.  Therefore, extracting suberin from bark and depolymerizing it into its constituent fatty acids holds significant economic and sustainability benefits.

Currently used chemical extraction methods for fatty acids rely on harsh solvents andenergy-intensive processes. Therefore, the development of an enzymatic extraction process holds significant appeal in terms of promoting a more sustainable and resource-efficient approach to the valorization of residual bark, thus benefitting both industry and the environment. However, the challenge here is that, by nature of their biological role in plant defense, suberins are generally resistant to microbial degradation, and very few suberin-active esterases have been characterized.

In this project, we aim to develop a lab-scale process for fatty acid extraction from hardwood (birch) bark using suberinases from two acidophilic fungi- Penicillium sp4. ASM 115 and Talaromyces sp. AS 616-3. The genomes of these fungi have predicted extracellular esterases that are orthologous to previously reported suberinases. In addition to developing and optimizing the enzymatic extraction process, we will also investigate the biochemical and structural features of these enzymes in order to comprehensively understand them.