The phenolic units in various parts of ligninare converted to o-diphenolic units by demethylation and by aromatic hydroxylation (ring preparation by monooxygenases). The o-diphenolic units are cleaved to produce carboxy-rich aliphatic residues (ring cleavage by dioxygenases) which are then degraded, through both hydrolytic and oxidative reactions, to release low-molecular-weight  aliphatic products which enter the fungal hyphae.

As suggested above, degradation products may vary accorging to type of fungus used. But in general polyphenols and lignin conjugates with sugars (in case of natural lignocellulosic substrate). links will be helpful for you.

http://www.annualreviews.org/doi/abs/10.1146/annurev.mi.41.100187.002341?journalCode=micro

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3815837/

Hi 

in general, degradation products are hydroxycinnamaldehydes (as vanillin and 4-hydroxycinnamaldehyde) and hydroxycinnamis acids (ferulic and 4-coumaric acid). However, products may vary according fungus applied.

best wishes