Lignin-modifying enzyme

LMEs have been known to be produced by many species of white rot basidiomycetous fungi, including: Phanerochaete chrysosporium, Ceriporiopsis subvermispora, Trametes versicolor, Phlebia radiata, Pleurotus ostreatus and Pleurotus eryngii.

LMEs are produced not only by wood-white rotting fungi but also by litter-decomposing basidiomycetous fungi such as Agaricus bisporus (common button mushroom), and many Coprinus and Agrocybe species. The brown-rot fungi, which are able to colonize wood by degrading cellulose, are only able to partially degrade lignin.

Some bacteria also produce LMEs, although fungal LMEs are more efficient in lignin degradation. Fungi are thought to be the most substantial contributors to lignin degradation in natural systems.

LMEs and cellulases are crucial to ecologic cycles (for example, growth/death/decay/regrowth, the carbon cycle, and soil health) because they allow plant tissue to be decomposed quickly, releasing the matter therein for reuse by new generations of life. LMEs are also crucial to a number of different industries.

Industry Application

Lignin-modifying enzymes have been actively used in the paper and pulp industry for the last decade. They were used in the industry shortly after they were discovered to have both detoxifying and decolorizing properties; properties that the pulp industry spends over $100 million USD annually on to pursue. Although these enzymes have been applied to industry for the last ten years, optimal and robust fermentative processes have not been established. There is an area of active research as scientists believe that the lack of optimal conditions for these enzymes are limiting industrial exploitation.

Lignin-modifying enzymes benefit industry as they can break down lignin; a common waste product of the paper and pulp industry. These enzymes have been used in the refinement of poplar as lignin inhibits the enzymatic hydrolysis of treated poplar and Lignin-modifying enzymes can efficiently degrade the lignin thus fixing this problem.

Another use of lignin modifying enzymes is the optimization of plant biomass use. Historically, only a small fraction of plant biomass use could actually be extracted from pulp sources leaving the majority of the plants as waste products. Due to Lignin, the plant waste is relatively inert towards degradation and causes the large accumulation of waste products. LMEs can effectively break it down into other aromatic compounds.

LMEs were initially used for the bleaching of waste effluent. Now there are several patented processes that make use of these enzymes for pulp bleaching, many of which are still under development.

The environmental industry has interest in using LMEs for the degradation of xenobiotic compounds. There is active research into the detoxification of herbicides by LMEs. Trametes versicolor was shown to effectively degraded Glyphosate in vitro.