Sweet spots for fungal lignocellulose degradation; Surface analysis tools to identify activity of Aspergillus niger and its enzymes on wheat straw

Fungi are able to degrade lignocellulose in plant biomass, and we already exploit their enzymes on industrial scale to produce simple sugars from agricultural lignocellulose waste. We have poor knowledge of the effect of fungi and their enzymes on the actual insoluble complex substrate, while such understanding underpins exploitation of enzymes to make designer polysaccharide materials, effective degradative enzyme cocktails and to engineer fungal production strains.

I investigated how exposure and accessibility of polysaccharides and lignin on lignocellulose surface changes during cultivation with industrially relevant fungus Aspergillus niger, with the aim to understand how this fungus and its enzymes interacts with lignocellulose.

I’ll discuss how analysis of time-staged changes of lignocellulose by mass-spectrometry based imaging, identified that surface exposure of lignin and proteins was increased over time.  Differential degradation of polysaccharides xylan, xyloglucan, pectin and mixed-linkage beta-glucan were identified using immunohistochemistry. I’ll also show that carbohydrate arrays coupled with mass spectrometry can be applied to identify reaction products of its carbohydrate active enzymes. Overall, the results highlight that full understanding of fungal and enzymatic lignocellulose degradation requires a combination of enzyme biochemical data with identification of modifications in real, complex lignocellulose materials. 

More on Dr Jolanda van Munster.