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Original- "Lignin-modifying enzymes"

Lignin-modifying enzymes (LMEs) are various types of enzymes produced by fungi that catalyze the breakdown of lignin, a biopolymer commonly found in the cell walls of plants. The terms ligninases and lignases are older names for the same class, but the name "lignin-modifying enzymes" is now preferred, given that these enzymes are not hydrolytic but rather oxidative (electron withdrawing) by their enzymatic mechanisms. LMEs include peroxidases, such as lignin peroxidase (EC 1.11.1.14), manganese peroxidase (EC 1.11.1.13), versatile peroxidase (EC 1.11.1.16), and many phenoloxidases of the laccase type.

LMEs have been known to be produced by many species of so-called 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 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 laccases in combinations with organic charge transfer mediator compounds. Laccases are more widely distributed enzymes belonging to the multicopper oxidase (MCO) superfamily encompassing all three domains of life (bacteria, archaea, eukarya).

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.







Edit- "Lignin-modifying enzymes"

Lignin-modifying enzymes (LMEs) are various types of enzymes produced by fungi that catalyze the breakdown of lignin, a biopolymer commonly found in the cell walls of plants. The terms ligninases and lignases are older names for the same class, but the name "lignin-modifying enzymes" is now preferred, given that these enzymes are not hydrolytic but rather oxidative (electron withdrawing) by their enzymatic mechanisms. LMEs include peroxidases, such as lignin peroxidase (EC 1.11.1.14), manganese peroxidase (EC 1.11.1.13), versatile peroxidase (EC 1.11.1.16), and many phenoloxidases of the laccase type.

LMEs have been known to be produced by many species of so-called 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 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 laccases in combinations with organic charge transfer mediator compounds. Laccases are more widely distributed enzymes belonging to the multicopper oxidase (MCO) superfamily encompassing all three domains of life (bacteria, archaea, eukarya).

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[edit]

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.[1]. 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[2].

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[3].

Another use of lignin modifying enzymes is the optimization of plant biomass use[4]. 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[5].

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.[6]

[edit]

  1. ^ Gonçalves, Luisa. "Use of Laccase for Bleaching of Pulps and Treatment of Effluents". ACS Publications. ACS Publications. Retrieved 8 October 2017.
  2. ^ Martani, F.; Lotti, M.; Porro, D. "The importance of fermentative conditions for the biotechnological production of lignin modifying enzymes from white-rot fungi". Pubmed. Oxford Academic. Retrieved 8 October 2017.
  3. ^ Richard, Chandra; Na, Zhong. "The influence of lignin on steam pretreatment and mechanical pulping of poplar wood to achieve high sugar recovery and ease of enzymatic hydrolysis". Science Direct. Bioresource Technology. Retrieved 8 October 2017.
  4. ^ Dana, Colpa; Gonzalo, Gonzalo. "Bacterial enzymes involved in lignin degradation". Science Direct. Journal of Biotechnology. Retrieved 8 October 2017.
  5. ^ Raghukumar, C.; D’Souza, T. "Lignin-Modifying Enzymes of Flavodon flavus, a Basidiomycete Isolated from a Coastal Marine Environment". Pubmed. AEM Journal. Retrieved 8 October 2017.
  6. ^ Coelho-Moreira, Jaqueline. "Involvement of Lignin-Modifying Enzymes in the Degradation of Herbicides". INTECH. Agricultural and Biological Sciences. Retrieved 20 November 2017.

Ben willox (talk) 20:26, 19 November 2017 (UTC)