Review: lignin conversion by manganese peroxidase (MnP)

Hofrichter, Martin

doi:10.1016/s0141-0229(01)00528-2

Cited by 875 publications

(537 citation statements)

References 131 publications

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“…Microbial Mn oxidation has long been implicated in the enzymatic degradation of lignin (16). Culture studies with lignindecomposing fungi showed that trivalent Mn 3+ is generated during the oxidation of lignin model compounds (17).…”

mentioning

confidence: 99%

Long-term litter decomposition controlled by manganese redox cycling

Keiluweit

Nico

Harmon

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

197

156

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Litter decomposition is a keystone ecosystem process impacting nutrient cycling and productivity, soil properties, and the terrestrial carbon (C) balance, but the factors regulating decomposition rate are still poorly understood. Traditional models assume that the rate is controlled by litter quality, relying on parameters such as lignin content as predictors. However, a strong correlation has been observed between the manganese (Mn) content of litter and decomposition rates across a variety of forest ecosystems. Here, we show that long-term litter decomposition in forest ecosystems is tightly coupled to Mn redox cycling. Over 7 years of litter decomposition, microbial transformation of litter was paralleled by variations in Mn oxidation state and concentration. A detailed chemical imaging analysis of the litter revealed that fungi recruit and redistribute unreactive Mn 2+ provided by fresh plant litter to produce oxidative Mn 3+ species at sites of active decay, with Mn eventually accumulating as insoluble Mn 3+/4+ oxides. Formation of reactive Mn 3+ species coincided with the generation of aromatic oxidation products, providing direct proof of the previously posited role of Mn 3+ -based oxidizers in the breakdown of litter. Our results suggest that the litter-decomposing machinery at our coniferous forest site depends on the ability of plants and microbes to supply, accumulate, and regenerate short-lived Mn 3+ species in the litter layer. This observation indicates that biogeochemical constraints on bioavailability, mobility, and reactivity of Mn in the plant-soil system may have a profound impact on litter decomposition rates.terrestrial carbon cycle | nutrient cycling | forest soil ecosystems | soil-atmosphere interactions | climate change D ecomposition of above-ground plant detritus (litter) is a fundamental process regulating the release of nutrients for plant growth and the formation of soil organic matter (SOM) in forest ecosystems (1). Litter decomposition regulates the proportion of litter-derived carbon (C) that is either retained in the system as SOM or lost as CO 2 (2), thereby influencing net C storage in soils. Although even small decomposition rate increases may accelerate climate change by virtue of increasing CO 2 emissions from soils (3), uncertainty persists over the ratecontrolling mechanisms (4, 5).Litter decomposition rates are strongly influenced by climatic factors (e.g., temperature and moisture) and have long been linked to litter chemistry, specifically lignin content (6). Ligninan aromatic biopolymer-often makes up between 15% and 40% of the litter mass and is concentrated in cell walls (7). It encrusts cellulose microfibrils to form protective physical units ("ligno-cellulose complexes") that are embedded in a matrix of hemicellulose. Conventional thinking suggests that the relatively high initial litter decomposition rates are due to the preferential use of soluble and readily accessible polysaccharides and hemicelluloses relative to lignin components. In later stages, decompositi...

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mentioning

confidence: 99%

Long-term litter decomposition controlled by manganese redox cycling

Keiluweit

Nico

Harmon

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

197

156

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“…52,65 Além disso, os íons ferro podem ser utilizados por fungos causadores de podridão parda para gerar radicais hidroxila via reação de Fenton, visto que H 2 O 2 é produzido pela maioria deles. 29 Os radicais hidroxila são fortes oxidantes que ocasionam a rápida despolimerização dos polissacarídeos, além de poderem ocasionar a inserção de novas hidroxilas nos anéis aromáticos da lignina (para uma revisão ver ref.…”

Section: Sistema Fentonunclassified

Mecanismos envolvidos na biodegradação de materiais lignocelulósicos e aplicações tecnológicas correlatas

Aguiar¹,

Ferraz²

2011

Quím. Nova

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Recebido em 9/11/10; aceito em 21/6/11; publicado na web em 8/8/11MECHANISMS INVOLVED IN THE BIODEGRADATION OF LIGNOCELLULOSIC MATERIALS AND RELATED TECHNOLOGICAL APPLICATIONS. The biodegradation of lignocellulosic materials is an important natural process because it is responsible for the carbon recycling. When induced under controlled conditions, this process can be used for technological applications such as biopulping, biobleaching of cellulosic pulps, pre-treatment for subsequent saccharification and cellulosic-ethanol production, and increase of the digestibility in agroindustrial residues used for animal feed. In the present work, the enzymatic and non-enzymatic mechanisms involved in the biodegradation of lignocellulosic materials by fungi were reviewed. Furthermore, the technological applications of these extracellular metabolites are presented and discussed.Keywords: wood biodegradation; oxidative enzymes; Fenton reaction. INTRODUÇÃOA biodegradação dos materiais lignocelulósicos tem sido objeto de muitos estudos, pois, além de corresponder a uma importante etapa do ciclo do carbono na natureza, também pode ser aplicada em processos tecnológicos. As aplicações em questão são variadas e incluem desde a ação direta de fungos sobre a madeira, desenhada como uma etapa de pré-tratamento aos processos de fabricação de celulose e papel, 1,2 até processos que usam os fungos decompositores de materiais lignocelulósicos como agentes indutores da degradação de compostos xenobióticos, quer em solos contaminados 3 ou em efluentes industriais. 4 O pré-tratamento de materiais lignocelulósicos com fungos também tem sido apontado como uma forma de facilitar processos subsequentes de conversão da celulose em açúcares fermentescíveis destinados à bioconversão em etanol e outros produtos de interesse comercial. 5,6 Também na área de nutrição animal, a aplicação de fungos decompositores de materiais lignocelulósicos tem sido descrita. Nesse caso, o pré-tratamento biológico é usado para aumentar a digestibilidade de resíduos agroindustriais utilizados na alimentação de ruminantes e não ruminantes. Os fungos, principalmente os causadores de podridão branca seletivos na degradação de lignina, desestruturam a parede celular vegetal, promovendo a conversão dos polissacarídeos em açúcares de fácil assimilação. Além disso, a biomassa fúngica que se desenvolve sobre o lignocelulósico pode servir como fonte de proteína. 7 A aplicação de enzimas produzidas pelos fungos decompositores de materiais lignocelulósicos também tem ganhado muito interesse na atualidade. O uso de xilanases 8 e lacases 9,10 em processos de branqueamento de polpas celulósicas e a aplicação de celulases na hidrólise enzimática de celulose nos processos de produção de etanol de segunda geração, 11 são exemplos de como o avanço no entendimento da biodegradação dos lignocelulósicos tem permitido explorar aplicações tecnológicas de grande relevância para o mundo moderno.O desenvolvimento das aplicações mencionadas anteriormente tem ocorrido de forma simultânea à ger...

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“…The chelated Mn 3+ is able to diffuse into the plant cell wall structures and acts as an oxidative mediator (Blanchette 1984. It can oxidise phenolic structures of lignin and other aromatic compounds (Zapanta & Tien 1997, Hofrichter 2002. MnP is the only fungal enzyme able to oxidise organic structures to carbon dioxide (CO 2 ), thus performing an enzymatic combustion , Hofrichter 2002.…”

Section: Enzyme Reactionmentioning

confidence: 99%

“…It can oxidise phenolic structures of lignin and other aromatic compounds (Zapanta & Tien 1997, Hofrichter 2002. MnP is the only fungal enzyme able to oxidise organic structures to carbon dioxide (CO 2 ), thus performing an enzymatic combustion , Hofrichter 2002. The oxidative ability of MnP can be enhanced by presence of additional co-oxidants such as unsaturated lipids and thiols (Forrester et al 1988, Wariishi et al 1989, van Aken et al 2000, Bermek et al 2002.…”

Section: Enzyme Reactionmentioning

confidence: 99%

Wood production, wood technology, and biotechnological impacts

Kües¹

2007

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Review: lignin conversion by manganese peroxidase (MnP)

Cited by 875 publications

References 131 publications

Long-term litter decomposition controlled by manganese redox cycling

Long-term litter decomposition controlled by manganese redox cycling

Mecanismos envolvidos na biodegradação de materiais lignocelulósicos e aplicações tecnológicas correlatas

Wood production, wood technology, and biotechnological impacts

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