Visible surface growth of actinomycetes is also possible and in papers on composting, they have been referred to as a white limelike coating , chalky white encrustation or to cause the fire-fang of compost. They say that a lot of these chemicals are structurally similar to lignin. The white rot fungi are said to be specialized in decomposing lignin, and this ability seems to carry over to a lot of manufactured organic chemicals. These fungi are mesophilic so they colonize compost only when temperature gets down. Lignin is a complex polyphenol and so it is usually the last fraction of carbon to be degraded.
Fungi are the principal microorganisms capable to degrade lignin.
They are divided in 3 group. The Brown rot mainly decompose the polysaccharide in wood. They cause only a limited decrease in the lignin content. The white rot fungi are capable to degrade all the major components of wood and are generally considered to be the main agents of lignin decomposition. Usually the fungi called white rot or brown rot fungi are Basidiomycetes .