Biobleaching of unbleached and oxygen-bleached hardwood kraft pulp by culture filtrate containing manganese peroxidase and lignin peroxidase fromPhanerochaete chrysosporium

1998 ◽  
Vol 44 (6) ◽  
pp. 451-456 ◽  
Author(s):  
Takeshi Iimori ◽  
Shoichi Miyawaki ◽  
Makoto Machida ◽  
Kunichika Murakami
Keyword(s):  
Culture Filtrate ◽  
Lignin Peroxidase ◽  
Manganese Peroxidase ◽  
Kraft Pulp

scholarly journals Congo Red Decolorization and Detoxification by Aspergillus niger: Removal Mechanisms and Dye Degradation Pathway

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Nedra Asses ◽  
Lamia Ayed ◽  
Neila Hkiri ◽  
Moktar Hamdi
Keyword(s):  
Molecular Structure ◽  
Aspergillus Niger ◽  
Azo Dyes ◽  
Lignin Peroxidase ◽  
Congo Red ◽  
Manganese Peroxidase ◽  
Dye Degradation ◽  
Degradation Pathway ◽  
Effects Of Ph ◽  
Maximum Decolorization

Congo red is one of the best known and used azo dyes which has two azo bonds (-N=N-) chromophore in its molecular structure. Its structural stability makes it highly toxic and resistant to biodegradation. The objective of this study was to assess the congo red biodegradation and detoxification by Aspergillus niger. The effects of pH, initial dye concentration, temperature, and shaking speed on the decolorization rate and enzymes production were studied. The maximum decolorization was correlated with lignin peroxidase and manganese peroxidase production. Above 97% were obtained when 2 g mycelia were incubated at pH 5, in presence of 200 mg/L of dye during 6 days at 28°C and under 120 to 150 rpm shaking speed. The degraded metabolites were characterized by using LC-MS/MS analyses and the biodegradation mechanism was also studied. Congo red bioconversion formed degradation metabolites mainly by peroxidases activities, i.e., the sodium naphthalene sulfonate (m/z = 227) and the cycloheptadienylium (m/z = 91). Phytotoxicity and microtoxicity tests confirmed that degradation metabolites were less toxic than original dye.

scholarly journals Studies on the Production of Fungal Peroxidases inAspergillus niger

2000 ◽  
Vol 66 (7) ◽  
pp. 3016-3023 ◽  
Author(s):  
Ana Conesa ◽  
Cees A. M. J. J. van den Hondel ◽  
Peter J. Punt
Keyword(s):  
Lignin Peroxidase ◽  
Manganese Peroxidase ◽  
Culture Medium ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Limiting Factors ◽  
Efficient Production ◽  
Mrna Levels ◽  
Extracellular Medium

ABSTRACT To get insight into the limiting factors existing for the efficient production of fungal peroxidase in filamentous fungi, the expression of the Phanerochaete chrysosporium lignin peroxidase H8 (lipA) and manganese peroxidase (MnP) H4 (mnp1) genes in Aspergillus niger has been studied. For this purpose, a protease-deficient A. niger strain and different expression cassettes have been used. Northern blotting experiments indicated high steady-state mRNA levels for the recombinant genes. Manganese peroxidase was secreted into the culture medium as an active protein. The recombinant protein showed specific activity and a spectrum profile similar to those of the native enzyme, was correctly processed at its N terminus, and had a slightly lower mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Recombinant MnP production could be increased up to 100 mg/liter upon hemoglobin supplementation of the culture medium. Lignin peroxidase was also secreted into the extracellular medium, although the protein was not active, presumably due to incorrect processing of the secreted enzyme. Expression of the lipA and mnp1 genes fused to the A. niger glucoamylase gene did not result in improved production yields.

Probing molecular basis of single-walled carbon nanotube degradation and nondegradation by enzymes based on manganese peroxidase and lignin peroxidase

RSC Advances ◽  
2016 ◽  
Vol 6 (5) ◽  
pp. 3592-3599 ◽  
Author(s):  
Ming Chen ◽  
Xiaosheng Qin ◽  
Jian Li ◽  
Guangming Zeng
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Adverse Effects ◽  
Human Health ◽  
Lignin Peroxidase ◽  
Manganese Peroxidase ◽  
Molecular Basis ◽  
Single Walled Carbon Nanotube ◽  
Single Walled Carbon

Increasing evidence has shown that carbon nanotubes (CNTs) present adverse effects on the environment and human health, which stresses the importance of exploring CNT biodegradation.

scholarly journals Linking Enzymatic Oxidative Degradation of Lignin to Organics Detoxification

2018 ◽  
Vol 19 (11) ◽  
pp. 3373 ◽  
Author(s):  
Xiaolu Wang ◽  
Bin Yao ◽  
Xiaoyun Su
Keyword(s):  
Redox Potential ◽  
Lignin Peroxidase ◽  
Manganese Peroxidase ◽  
Lignin Degradation ◽  
Oxidative Degradation ◽  
Class Ii ◽  
Substrate Preference ◽  
Versatile Peroxidase

The major enzymes involved in lignin degradation are laccase, class II peroxidases (lignin peroxidase, manganese peroxidase, and versatile peroxidase) and dye peroxidase, which use an oxidative or peroxidative mechanism to deconstruct the complex and recalcitrant lignin. Laccase and manganese peroxidase directly oxidize phenolic lignin components, while lignin peroxidase and versatile peroxidase can act on the more recalcitrant non-phenolic lignin compounds. Mediators or co-oxidants not only increase the catalytic ability of these enzymes, but also largely expand their substrate scope to those with higher redox potential or more complicated structures. Neither laccase nor the peroxidases are stringently selective of substrates. The promiscuous nature in substrate preference can be employed in detoxification of a range of organics.

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