Lignin-modifying enzymes from selected white-rot fungi: production and role from in lignin degradation

Hatakka, Annele

doi:10.1016/0168-6445(94)90076-0

Cited by 303 publications

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“…Manganese peroxidase (MnP) 1 is an extracellular heme protein produced by virtually all lignin-degrading white-rot fungi (1)(2)(3). Sequences have been determined for mnp cDNA (4,5) and genomic clones (6)(7)(8) encoding three MnP isozymes from Phanerochaete chrysosporium, the beststudied lignin-degrading fungus.…”

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Formation of a Bis(histidyl) Heme Iron Complex in Manganese Peroxidase at High pH and Restoration of the Native Enzyme Structure by Calcium

et al. 2000

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Manganese peroxidase (MnP) from Phanerochaete chrysosporium undergoes a pH-dependent conformational change evidenced by changes in the electronic absorption spectrum. This high-to lowspin alkaline transition occurs at ∼2 pH units lower in an F190I mutant MnP when compared to the wild-type enzyme. Herein, we provide evidence that these spectral changes are attributable to the formation of a bis(histidyl) heme iron complex in both proteins at high pH. The resonance Raman (RR) spectra of both ferric proteins at high pH are similar, indicating similar heme environments in both proteins, and resemble that of ferric cytochrome b 558 , a protein that contains a bis-His iron complex. Upon reduction with dithionite at high pH, the visible spectra of both the wild-type and F190I MnP exhibit absorption maxima at 429, 529, and 558 nm, resembling the absorption spectrum of ferrous cytochrome b 558 . RR spectra of the reduced wild-type and F190I mutant proteins at high pH are also similar to the RR spectrum of ferrous cytochrome b 558 , further suggesting that the alkaline low-spin species is a bis(histidyl) heme derivative. No shift in the low-frequency RR bands was observed in 75% 18 O-labeled water, indicating that the low-spin species is most likely not a hydroxo-heme derivative. Electronic and RR spectra also indicate that addition of Ca 2+ to either the ferric or ferrous enzymes at high pH completely restores the high-spin pentacoordinate species. Other divalent metals, such as Mn 2+ , Mg 2+ , Zn 2+ , or Cd 2+ , do not restore the enzyme under the conditions studied.Manganese peroxidase (MnP) 1 is an extracellular heme protein produced by virtually all lignin-degrading white-rot fungi (1-3). Sequences have been determined for mnp cDNA (4, 5) and genomic clones (6-8) encoding three MnP isozymes from Phanerochaete chrysosporium, the beststudied lignin-degrading fungus. These sequences and spectroscopic studies of the native and oxidized enzyme intermediates indicate that the heme environment of MnP is similar to that of other plant and fungal peroxidases (4,(9)(10)(11)(12)(13)(14). Kinetic and spectroscopic studies of the purified enzyme indicate a typical peroxidase reaction catalytic cycle:However, MnP is unique in its ability to efficiently oxidize Mn 2+ to Mn 3+ (9,15,16). The released Mn 3+ is stabilized by organic acid chelators, such as oxalate and malonate, which are secreted by the fungus (16, 17). The Mn 3+ -chelator complex is capable of diffusing from the enzyme to oxidize terminal substrates including lignin substructures, phenolic compounds, and pollutants (2, 3 and references therein, 18).The three amino acid residues believed to bind Mn 2+ , D179, E35, and E39, were investigated by site-directed mutagenesis of recombinant MnP homologously expressed in P. chrysosporium (19)(20)(21)(22). These studies, combined with X-ray crystal structure analyses of the proteins (23,24), confirmed that the side-chain carboxylates of D179, E35, and E39 form the only apparent Mn 2+ -binding site in MnP from P. chry...

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Formation of a Bis(histidyl) Heme Iron Complex in Manganese Peroxidase at High pH and Restoration of the Native Enzyme Structure by Calcium

et al. 2000

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“…Oxidoreductases expressed by certain white-rot and soft-rot fungi and even some bacteria catalyse lignin modification in nature as part of the global carbon biodegradation cycle [7][8][9]. Among these enzymes laccases (benzenediol:oxygen oxidoreductase, EC 1.10.3.2) uses molecular oxygen to catalyse oxidation of phenolic substrates similar to those found in lignin subunits.…”

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confidence: 99%

Direct rate assessment of laccase catalysed radical formation in lignin by electron paramagnetic resonance spectroscopy

Munk

Andersen

Meyer

2017

Enzyme and Microbial Technology

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Highlights Time course EPR measurement of direct radical formation by fungal laccases on genuine lignin samples  Assessment of enzyme kinetic rates of radical formation in lignin by two fungal laccases  Identification of different radical formation patterns by a low and high redox potential laccase  Demonstration of different laccase rates on different types of lignin substrates Abstract Laccases (EC 1.10.3.2) catalyse removal of an electron and a proton from phenolic hydroxyl groups, including phenolic hydroxyls in lignins, to form phenoxy radicals during reduction of O2. We employed electron paramagnetic resonance spectroscopy (EPR) for real time measurement of such catalytic radical 2 formation activity on three types of lignin (two types of organosolv lignin, and a lignin rich residue from wheat straw hydrolysis) brought about by two different fungal laccases, derived from Trametes versicolor (Tv) and Myceliophthora thermophila (Mt), respectively. Laccase addition to suspensions of the individual lignin samples produced immediate time and enzyme dose dependent increases in intensity in the EPR signal with g-values in the range 2.0047-2.0050 allowing a direct quantitative monitoring of the radical formation and thus allowed laccase enzyme kinetics assessment on lignin. The experimental data verified that the laccases acted upon the insoluble lignin substrates in the suspensions. When the action on the lignin substrates of the two laccases were compared on equal enzyme dosage levels (by activity units on syringaldazine) the Mt laccase exerted a significantly faster radical formation than the Tv laccase on all three types of lignin substrates. When comparing the equal laccase dose rates on the three lignin substrates the enzymatic radical formation rate on the wheat straw lignin residue was consistently higher than that of the organosolv lignins. The pH-temperature optimum for the radical formation rate in organosolv lignin was determined by response surface methodology to pH 4.8, 33°C and pH 5.8, 33°C for the Tv laccase and the Mt laccase, respectively. The results verify direct radical formation action of fungal laccases on lignin without addition of mediators and the EPR methodology provides a new type of enzyme assay of laccases on lignin.

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“…Berdasarkan penelitian yang dilakukan Johan (2014) (Hatakka, 1994). Dengan adanya pendegradasi bahan lignoselulotik oleh jamur Pleurotus ostreatus diharapkan dapat meningkatkan kualitas pakan yang bersumber dari limbah pertanian.…”

Section: Pendahuluanunclassified

Evaluasi Nutrisi Limbah Kulit Durian (Durio zibethinus) yang Difermentasi Jamur Tiram Putih (Pleurotus ostreatus) pada Masa Inkubasi yang Berbeda

Suciyanti

Sulistyowati

Fenita

2016

JSPI.ID

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This research was aimed to evaluate nutrient contents of Durian (Durio zibethinus) peel by-product fermented with white rod fungi (Pleurotus ostreatus) in several durations of incubation. This fermented Durian (Durio zibethinus) peel by-product is expected to increase its nutrient contents and to decrease its fiber. The fermentation of Durian peel by-product using Pleurotus ostreatus were in duration of 2, 4, 6, and 8 weeks. The experiment was using completely randomized design, consisting of 5 treatments and 4 replications. The treatments were P0 (control, without fermentation), P1 (2 weeks fermentation), P2 (4 weeks fermentation), P3 (6 weeks fermentation), and P4 (8 weeks fermentation).Variables measured were moisture, dry matter, ash, organic matter, ether extract, protein, fiber, and nitrogen free extract. Results showed that the Durian peel by-product fermented during different incubation time, showed very very significant effect (P<0.001) on moisture, dry and organic matters, and ether extract; showed significant effect (P<0.05) on crude protein and fiber; but not significant (P>0.05) on ash and nitrogen free extract. These results showed that fermentation of Durian peel byproduct with white rod fungi (Pleurotus ostreatus) incubated in 8 weeks was able to increase crude protein and ash, but decrease the ether extract.Key words : Durian peel by-product, Pleurotus ostreatus, incubation. ABSTRAKPenelitian ini bertujuan untuk mengetahui kandungan nutrisi limbah kulit durian yang telah difermentasi menggunakan jamur tiram putih (Pleurotus ostreatus) pada masa inkubasi yang berbeda. Limbah kulit durian (LKD) yang difermentasi ini diduga dapat meningkatkan nilai nutrisi dan menurunkan kandungan serat kasar di dalam LKD. Fermentasi LKD menggunakan Pleurotus ostreatus dilakukan selama 2, 4, 6, dan 8 minggu. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) dengan 5 perlakuan dan 4 ulangan. Masingmasing perlakuan yaitu P0 (Perlakuan kontrol tanpa dilakukan proses fermentasi), P1 (fermentasi pada masa inkubasi 2 minggu), P2 (fermentasi pada masa inkubasi 4 minggu), P3 (fermentasi pada masa inkubasi 6 minggu), dan P4 (fermentasi pada masa inkubasi 8 minggu). Variabel yang diukur meliputi kadar air, bahan kering, abu, bahan organik, lemak kasar, protein kasar, serat kasar dan bahan ekstrak tanpa nitrogen. Hasil analisis ragam menunjukkan bahwa LKD yang difermentasi pada masa inkubasi yang berbeda berpengaruh sangat sangat nyata (P<0,001) terhadap kadar air, bahan kering, bahan organik, dan lemak kasar. Berpengaruh nyata (P<0,05) terhadap protein kasar dan serat kasar, serta berpengaruh tidak nyata (P>0,05) terhadap kadar abu dan bahan ekstrak tanpa nitrogen. Hasil penelitian menunjukkan bahwa LKD yang difermentasi dengan jamur tiram putih (Pleurotus ostreatus) pada masa inkubasi 8 minggu dapat meningkatkan protein kasar, dan kadar abu, serta menurunkan kadar lemak kasar.Kata Kunci : limbah kulit Durian, Pleurotus ostreatus, masa inkubasi, nutrisi ruminan PENDAHULUANPakan merupakan salah satu faktor penti...

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Lignin-modifying enzymes from selected white-rot fungi: production and role from in lignin degradation

Cited by 303 publications

References 0 publications

Formation of a Bis(histidyl) Heme Iron Complex in Manganese Peroxidase at High pH and Restoration of the Native Enzyme Structure by Calcium

Formation of a Bis(histidyl) Heme Iron Complex in Manganese Peroxidase at High pH and Restoration of the Native Enzyme Structure by Calcium

Direct rate assessment of laccase catalysed radical formation in lignin by electron paramagnetic resonance spectroscopy

Evaluasi Nutrisi Limbah Kulit Durian (Durio zibethinus) yang Difermentasi Jamur Tiram Putih (Pleurotus ostreatus) pada Masa Inkubasi yang Berbeda

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