Evaluation of king oyster and shiitake fungi in the collection of Plant Breeding WUR on selective ligin degradation

The fungal collection of Plant Breeding WUR contains a large number of strains that produce edible mushrooms and are also known as white rot fungi. Good examples are the species Lentinula edodes (shiitake) and Pleurotus eryngii (king oyster mushroom) of which the collection contains 154 and 99 strains, respectively. Both collections were genotyped in this project and showed a large genetic variation.<br/>Two types lignocellulosic rich substrates were used in this project for selective removal of lignin by fungi. Wheat straw as a crop residue that is available throughout Europe and Miscanthus as one of the best energy crops worldwide.<br/>P. eryngii appears to grow not well on Miscanthus and was thus only evaluated on wheat straw. Lentinula edodes grows well on Miscanthus.<br/>A dedicated selection of 20 P. eryngii strains showed a significant variation in the extent of lignin degradation in wheat straw indicating that mining collections is a way to improve the selective removal of lignin in lignocellulosic materials. The improvement is needed to make the fungal treatment competitive to the now-a-days used chemical and/or physical methods. The variation in selective lignin degradation also generates a basis to breed fungi with a better performance.<br/>A pre-test of 3 L. edodes strain on 2 varieties of Miscanthus showed that there is variation between strain in the extent of lignin degradation. This seems not to depend on the amount of lignin in Miscanthus.<br/>The next steps in the project will be an evaluation of a large selection of strains of L. edodes on selective removal of lignin in Miscanthus and the evaluation of the effect of selective lignin removal by P. eryngii in wheat straw and L. edodes in Miscanthus on the digestibility by ruminants using the in vitro gas production technique (Cone et al, 1996) and saccharification by enzymes