Enzymes: Nature’s own scissors

​Swedish forests can be used for the production of fuels or sustainable materials. But the structure of wood is recalcitrant and hard to decompose. Jenny Arnling Bååth’s research is on enzymes, that might help make wood more accessable for production of new materials.
​Forestry materials can be used to make bioethanol, biochemicals, textiles or materials to replace composites and plastics. In other words: Our Swedish forests are a gold mine for the production of sustainable alternatives.

But there are some difficulties. One is the recalcitrance of wood – it’s very hard to decompose.

Wood consists of three elements: Cellulose, lignin and hemicellulose. The cellulose is the core, while lignin and hemicellulose form a net and a glue that will protect the tree in its natural environment.
If the tree is completely decomposed we get simple sugars, which is used for the production of ethanol. But the different parts – the polymers – in wood can also be used for different things, and there is much to gain by cutting different bonds between the different wood polymers. Maybe we want to extract just the lignin, or just the hemicellulose, instead of decomposing it all into a mixture of the smallest building bricks.

Jenny Arnling Bååth, a PhD student at the Department of Biology and Biological Engineering, is working with enzymes. Enzymes are nature’s own scissors, and cut bonds to help dissolve wood polymers, as well as making the food’s nutrients available in our stomachs. Jenny Arnling Bååth was recently able to show that a certain enzyme, glucuronoyl esterase, is able to cleave a specific bond in the so called lignin-carbohydrate complex. Her research might therefore pave the way for effective and intact extraction of wood polymers in industrial processes.
– We knew that this enzyme can cleave the bonds in model substrates, that is, in simplified chemicals or molecules. This time we grinded wood into a powder, processed it and got lignin and hemicellulose in pure fractions, she says.
– Our research is the first to show that this enzyme can actually cut the bonds in real substrate from wood. We have worked on this for a long time. It takes luck and time to succeed.

The use of enzymes in industrial production is also environmental friendly. Without these natural scissors the wood will need treatment at high temperatures or with chemicals that are potentially dangerous. Furthermore, the enzymes only preform one task – the reactions will always remain controlled.
– We don’t know the impact of enzymes in industrial applications yet. Now we want to focus on gaining further knowledge; we want to know more about their resistance when it comes to things like pH or temperatures, and we also want to characterize them – what they do, how fast, and their similarities in regards to structure and function.

The findings of Jenny Arnling Bååth is a result of the collaborations within Wallenberg Wood Science Center (link below) which means that she has been able to perform analyses at KTH Royal Institute of Technology in Stockholm. She praises the benefits of the center:
– We work closely together with scientists from different disciplines. As biochemists, we look at enzymes, while other groups work with the same questions but from different angles. A person specialized in Wood Chemistry and a biochemist is not the same. It’s nice to keep on working together.

Read more about the Wallenberg Wood Science Center here.

Text: Mia Malmstedt
Photo: Martina Butorac

Published: Fri 28 Sep 2018.