Mining the secretome of the lignocellulose degrading fungus Parascedosporium putredinis NO1

The demand for sustainable and renewable alternatives to finite and environmentally damaging fossil fuel resources is growing. Lignocellulosic biomass is available in vast amounts, at low cost, and could provide fuels, chemicals, and materials if deconstructed effectively. However, its recalcitrant nature makes the cost-effective utilisation of this substrate difficult to achieve. Despite this, wood-degrading fungi have evolved an array of powerful enzymes for the deconstruction of all components of lignocellulose including the polysaccharides and the aromatic polymer lignin.
In this work, the lignocellulose-degrading capacity of the ascomycete fungus Parascedosporium putredinis NO1 was explored in detail. New bioinformatic strategies were developed and employed to probe the genome of P. putredinis NO1, the first genome of its genus, and to isolate an in silico secretome to allow clearer characterisation of the biomass-degrading response. Proteomic investigations of the growth of P. putredinis NO1 on multiple industrially relevant lignocellulosic substrates demonstrated remarkable variation in the P. putredinis NO1 secretome depending on growth substrate. Molecular techniques were used to expand the demonstration of the varied secretome temporally and support the hypothesis of a tailored enzymatic response to different lignocellulosic substrates, an understanding of which will be important for the development of efficient biorefinery technology.
The tailored secretome was exploited by investigating the enzymatic response of P. putredinis NO1 when grown on substrates with varying lignin contents. This allowed identification of proteins with patterns of abundance suggesting roles in the breakdown of lignin. The characterisation of lignocellulose-degrading organisms from underexplored branches of the tree of life, and the identification and characterisation of new enzymes with unclear or unknown roles in lignocellulose breakdown will be vital to improving our understanding of lignocellulose deconstruction and to achieve this efficiently in biorefineries.