Ligninase is the original term encompassing many different types of oxidative, extracellular fungal enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

s which catalyze the breakdown of lignin

Lignin

Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants and some algae. The term was introduced in 1819 by de Candolle and is derived from the Latin word lignum, meaning wood...

 which is commonly found in the cell walls

Cell wall

The cell wall is the tough, usually flexible but sometimes fairly rigid layer that surrounds some types of cells. It is located outside the cell membrane and provides these cells with structural support and protection, and also acts as a filtering mechanism. A major function of the cell wall is to...

 of plants

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

. Instead of the term ligninase, the term lignin-modifying enzymes (LMEs) should be used, since these enzymes are not hydrolytic but oxidative (electron withdrawing) by their enzymatic mechanisms. LMEs include peroxidases, such as Lignin peroxidase

Lignin peroxidase

Lignin is highly resistant to biodegradation and only higher fungi are capable of degrading the polymer via an oxidative process. This process has been studied extensively in the past twenty years, but the actual mechanism has not yet been fully elucidated...

, Manganese peroxidase

Manganese peroxidase

In enzymology, a manganese peroxidase is an enzyme that catalyzes the chemical reactionThe 3 substrates of this enzyme are Mn, H+, and H2O2, whereas its two products are Mn and H2O....

 and Versatile peroxidase, and many phenol-oxidases of Laccase

Laccase

Laccases are copper-containing oxidase enzymes that are found in many plants, fungi, and microorganisms. The copper is bound in several sites; Type 1, Type 2, and/or Type 3. The ensemble of types 2 and 3 copper is called a trinuclear cluster . Type 1 copper is available to action of solvents,...

 type.

LMEs have been known to be produced by many species of so called white rot basidiomyceotus Fungi including: Phanerochaete chrysosporium, Ceriporiopsis subvermispora, Trametes versicolor

Trametes versicolor

Trametes versicolor — formerly known as Coriolus versicolor and Polyporus versicolor — is an extremely common polypore mushroom which can be found throughout the world. Versicolor means 'of several colours' and it is true that this mushroom is found in a wide variety of different colours. T...

, Phlebia radiata, Pleurotus ostreatus and Pleurotus eryngii

Pleurotus eryngii

Pleurotus eryngii is an edible mushroom native to Mediterranean regions of Europe, the Middle East, and North Africa, but also grown in parts of Asia.In Italian it is called cardoncello; in Chinese, it is called xìng bào gū Pleurotus eryngii (also known as king trumpet mushroom, French horn...

.

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

Coprinus

Coprinus is a small genus of mushrooms consisting of Coprinus comatus and several of its close relatives. Until 2001, Coprinus was a large genus consisting of all agaric species in which the lamellae autodigested to release their spores...

and Agrocybe

Agrocybe

Agrocybe, including edible fungi such as the Agrocybe cylindracea, is a genus of mushroom with similar characteristics to the Tricholoma matsutake, Agrocybe aegerita and Agrocybe parasitica. Some are poisonous mushrooms...

species. The brown-rot fungi, which are able to colonize wood by degrading cellulose, are not able to produce LMEs.

Some results on LME-type of peroxidases have also been reported for some species of filamentous bacteria such as Streptomyces viridosporus T7A, Streptomyces lavendulae REN-7 and Clostridium stercorarium.

However, efficient lignin and lignin-like polymer degradation is only achieved by fungal LME peroxidases, and laccase

Laccase

Laccases are copper-containing oxidase enzymes that are found in many plants, fungi, and microorganisms. The copper is bound in several sites; Type 1, Type 2, and/or Type 3. The ensemble of types 2 and 3 copper is called a trinuclear cluster . Type 1 copper is available to action of solvents,...

s in combinations with organic charge transfer mediator compounds. Laccases are more widely distributed enzymes belonging to the multicopper oxidase

Multicopper oxidase

In molecular biology, multicopper oxidases are enzymes which oxidise their substrate by accepting electrons at a mononuclear copper centre and transferring them to a trinuclear copper centre; dioxygen binds to the trinuclear centre and, following the transfer of four electrons, is reduced to two...

(MCO) superfamily encompassing all three domains of life (bacteria, archaea, eukarya).