Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.10.3.2 (laccase)
4,656 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to decolourise olive oil mill wastewaters (OOMW) efficiently, production and differential induction of ligninolytic enzymes by the white rot Coriolopsis polyzona, were studied by varying growth media composition and/or inducer addition. Among various possible inducers, veratryl alcohol appeared to be the most efficient to enhance specific productions of lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase by a factor of 18.5, 20.8 and 55, respectively. Ligninolytic enzymes were better produced in glucose based medium with a low nitrogen level (2.2 mM) under O2 atmosphere. The addition of 5 mM veratryl alcohol resulted in a maximal production of LiP, whereas maximal MnP and laccase were obtained at 10 mM. LiP production was totally repressed in presence of 100 microM Mn2+. The extrapolation of these conditions on OOMW based media was carried out at different effluent dilutions and the possible role of the different ligninolytic enzymes in OOMW decolourisation was studied. A better effluent decolourisation was obtained under LiP induction condition (5 mM veratryl alcohol) than when LiP was repressed (100 microM Mn2+). Furthermore, high levels of laccase had a detrimental effect on OOMW decolourisation concomitant to the formation of soluble polymeric aromatic compounds.
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PMID:Lignin modifying enzymes of Coriolopsis polyzona and their role in olive oil mill wastewaters decolourisation. 1603 61

Of the various types of industry-generated effluents, those containing organic pollutants such as phenols are generally difficult to remediate. There is a need to develop new technologies that emphasize the destruction of these pollutants rather than their disposal. In this work the white rot fungus, Trametes pubescens, was demonstrated to be an effective bioremediation agent for the treatment of phenolic wastewaters. An airlift loop reactor was optimized, in terms of volumetric oxygen transfer rate (K(L)a = 0.45 s(-1)), to provide an environment suited to rapid growth of T.pubescens (mu = 0.25 day(-1)) and a particularly efficient growth yield on glucose of 0.87 g biomass.g glucose(-1). The phenolic effluent was shown to be a paramorphogen, influencing fungal pellet morphology in the reactor, as well as increasing laccase enzyme activity by a factor of 5 over the control, to a maximum of 11.8 U.mL(-1). This increased activity was aided by the feeding of nonrepressing amounts (0.5 g.L(-1)) of glucose to the reactor culture. To our knowledge the degradation results represent the highest rate of removal (0.033 g phenol.g biomass(-1).day(-1)) of phenolic compounds from water reported for white rot fungi.
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PMID:Fungal bioremediation of phenolic wastewaters in an airlift reactor. 1608 Jun 85

Among carbon sources studied, cellobiose and mannitol provided the highest laccase (Lac) activity (648 and 742 U1(-1), respectively) of Trametes versicolor 775 while glucose gave maximum manganese peroxidase (MnP) and peroxidase activities (44 and 114 U1(-1), respectively). Citrus fruit peel as growth substrate enhanced Lac activity 7-fold when compared to the medium with cellobiose, whereas grape vine sawdust increased MnP and peroxidase activity up to 148 and 677 U1(-1), respectively.
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PMID:Carbon and nitrogen sources influence the ligninolytic enzyme activity of Trametes versicolor. 1609 92

Copper ion was necessary for the transcription of all laccase isozyme genes from Trametes sp. AH28-2, with higher concentrations of Cu2+ (1-2 mmol/L) being more favorable to the synthesis of laccase. In the glucose media containing 0.5 mmol/L Cu2+, the laccase activity of the supernate was rather low (44.3 u/L) and had an increase of 60.3% (71.0 u/L) when 4.0 mmol/L o-toluidine was added. Moreover, the activity reached up to 2584 u/L as the glucose was replaced by cellobiose. And Native-PAGE showed that LacA was the main laccase component if fungus was induced by o-toluidine or copper ions. It had been demonstrated by quantitative RT-PCR that the regulation of lacA expression, induced by o-toluidine, occurred at the transcriptional level, with the accumulation of mRNA transcripts being accompanied by the increase of laccase activity of the culture fluid. In addition, the structural gene of lacA interrupted by 10 introns was 2110 bp in length and the corresponding cDNA sequence was 1560 bp encoding a 520 aa protein, which had high similarities with other laccases from basidiomycetes. Furthermore, a length of 1881 bp of 5'-terminal sequence of transcription control of lacA, amplified by the improved inverse PCR, contained a TATA box, seven CAAT boxes as well as a number of putative cis-acting elements important for its expression, including five MREs, nine CreA-binding sites, four XREs, two STREs and seven nitrogen factor binding sites. The existence of these elements was well in agreement with the data obtained from Trametes sp. AH28-2 shaken-flask cultures.
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PMID:[Inducing synthesis of LacA from Trametes sp. AH28-2 and cloning & analysis of 5'-terminal sequence of transcription control of the gene]. 1617 90

Production of the lignin-degrading enzymes lignin peroxidase (Lip), manganese peroxidase (MnP), and laccase (Lac) by the white-rot fungus Bjerkandera adusta was investigated experimentally using polyurethane foam (PUF) as a carrier of immobilized fungal mycelia. An immobilized cell culture with a low-nitrogen medium yielded significantly greater LiP, MnP, and Lac activities in comparison with those obtained in a liquid culture. The maximum activities of the three enzymes were 450, 370, and 100 U/ml, respectively, under the following incubation condition: glucose concentration, 20 g/l; temperature, 30 degrees C; pH 4.5. The activities of MnP and Lac were significantly higher than those reported using other incubation methods. Lignin was degraded to the extent of 40% and its decolorization ratio was about 70% at an incubation time of 40 h using lignin-degrading enzymes from B. adusta. Six different isozymes of MnP were synthesized by B. adusta, two of which exhibited high MnP activity. Our preliminary finding that extracellular enzymes from B. adusta are capable of degrading and decoloring lignin makes these enzymes attractive for further research aimed at their large-scale application in lignin depolymerization, pulp biobleaching, and the degradation of toxic pollutants.
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PMID:Lignin-degrading enzyme production by Bjerkandera adusta immobilized on polyurethane foam. 1623 71

Bleach plant effluents from the pulp and paper industry generated during bleaching with chlorine-containing chemicals are highly colored and also partly toxic due to the presence of chloro-organics, hence the need for pretreatment prior to discharge. In a rotating biological contactor (RBC) reactor effluent decolorization was studied using Coriolus versicolor, a white-rot fungus and Rhizomucor pusillus strain RM7, a mucoralean fungus. Decolorization by both fungi was directly proportional to initial color intensities. It was found that the extent of decolorization was not adversely affected by color intensity, except at the lowest level tested. It was shown that decolorization of 53 to 73% could be attained using a hydraulic retention time of 23 h. With R. pusillus, 55% of AOX were removed compared to 40% by C. versicolor. Fungal treatment with both R. pusillus and C. versicolor rendered the effluent essentially nontoxic. Addition of glucose to decolorization media stimulated color removal by C. versicolor, but not with R. pusillus. Ligninolytic enzymes (manganese peroxidase and laccase) were only detected in effluent treated by C. versicolor. It seems that there are definite differences in the decoloring mechanisms between the white-rot fungus (adsorption + biodegradation) and the mucoralean fungus (adsorption). This aspect needs to be investigated in greater detail to verify the mode responsible for the decolorization activity in both types of fungi.
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PMID:Decolorization of bleach plant effluent by mucoralean and white-rot fungi in a rotating biological contactor reactor. 1623 95

Three novel laccase isozyme genes, lacA, lacB, and lacC, have been identified from basidiomycete Trametes sp. AH28-2. These genes display a high similarity with other basidiomycete laccases at the amino acid level. An inferred TATA box and several putative CAAT, MRE, XRE, and CreA consensus sequences were identified in the lacA, lacB, and lacC promoter regions. Different from the TATA boxes of lacA and lacB at about -100, the TATA box of lacC is located at -172. For all the isozymes, copper ion is essential for laccase synthesis in Trametes sp. AH28-2. More interestingly, different aromatic compounds can selectively induce the production of distinct laccase isozymes, with o-toluidine inducing the expression of laccase A (LacA) while 3,5-dihydroxytoluene mainly stimulating the production of laccase B (LacB). Quantitative reverse transcriptase-polymerase chain reaction showed that the accumulation of laccase messenger RNA transcripts is accompanied by the increase of corresponding enzyme activity in cultures. The glucose-repression effect on laccase expression in Trametes sp. AH28-2 was also observed. Furthermore, lower Cu2+ concentration (lower than 0.5 mM) can induce LacA and a novel laccase (LacC), and the latter will disappear when Cu2+ concentration is increased up to 1-2 mM. Upon induction by 3,5-dihydroxytoluene, the ratio of LacA to LacB decreased in the later phase of induction.
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PMID:Cloning of novel laccase isozyme genes from Trametes sp. AH28-2 and analyses of their differential expression. 1628 98

Effect of different nitrogen concentration in the mediums on growth and enzyme production of Phanerochaete chrysosporium was studied when glucose concentration was 10 g/L. The results showed that the medium contained 0.8 g/L ammonium tartrate is the best. It not only supply abundant nutrients for the growth of Phanerochaete chrysosporium, which make mycelia the best grow compared with the other medium, but also produce higher manganese-dependent peroxidase (Mnp) and laccase (Lac) activity. In addition, it is observed that the variation of mycelia surface is related to ligninolytic enzyme secreted by Phanerochaete chrysosporium. When the surface of mycelium pellets appeared burs, it predicts secondary metabolism begin. This experimentation demonstrated that when the ratio of carbon and nitrogen in nitrogen limited medium is equal to 100:8, growth and enzyme production of Phanerochaete chrysosporium is the best, it could achieve the maximum Mnp and Lac activity.
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PMID:Effect of nitrogen concentration in culture mediums on growth and enzyme production of Phanerochaete chrysosporium. 1629 86

Transformation of veratric (3,4-dimethoxybenzoic) acid by the white rot fungus Phlebia radiata was studied to elucidate the role of ligninolytic, reductive, and demeth(ox)ylating enzymes. Under both air and a 100% O(2) atmosphere, with nitrogen limitation and glucose as a carbon source, reducing activity resulted in the accumulation of veratryl alcohol in the medium. When the fungus was cultivated under air, veratric acid caused a rapid increase in laccase (benzenediol:oxygen oxidoreductase; EC 1.10.3.2) production, which indicated that veratric acid was first demethylated, thus providing phenolic compounds for laccase. After a rapid decline in laccase activity, elevated lignin peroxidase (ligninase) activity and manganese-dependent peroxidase production were detected simultaneously with extracellular release of methanol. This indicated apparent demethoxylation. When the fungus was cultivated under a continuous 100% O(2) flow and in the presence of veratric acid, laccase production was markedly repressed, whereas production of lignin peroxidase and degradation of veratryl compounds were clearly enhanced. In all cultures, the increases in lignin peroxidase titers were directly related to veratryl alcohol accumulation. Evolution of CO(2) from 3-OCH(3)-and 4-OCH(3)-labeled veratric acids showed that the position of the methoxyl substituent in the aromatic ring only slightly affected demeth(ox)ylation activity. In both cases, more than 60% of the total C was converted to CO(2) under air in 4 weeks, and oxygen flux increased the degradation rate of the C-labeled veratric acids just as it did with unlabeled cultures.
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PMID:Formation and Action of Lignin-Modifying Enzymes in Cultures of Phlebia radiata Supplemented with Veratric Acid. 1634 72

The ability of the white rot fungus Ceriporiopsis subvermispora to mineralize C-synthetic lignin was studied under different culture conditions, and the levels of two extracellular enzymes were monitored. The highest mineralization rates (28% after 28 days) were obtained in cultures containing a growth-limiting amount of nitrogen source (1.0 mM ammonium tartrate); under this condition, the levels of manganese peroxidase (MnP) and laccase present in the culture supernatant solutions were very low compared with cultures containing 10 mM of the nitrogen source. In contrast, cultures containing a limiting concentration of the carbon source (0.1% glucose) showed low levels of both enzymes and also very low mineralization rates compared with cultures containing 1% glucose. Cultures containing 11 ppm of Mn(II) showed a higher rate of mineralization than those containing 0.3 or 40 ppm of this cation. Levels of MnP and laccase were higher when 40 ppm of Mn(II) was used. Mineralization rates were slightly higher in cultures flushed daily with oxygen, whereas laccase levels were lower and MnP levels were approximately the same as in cultures maintained under an air atmosphere. The presence of 0.4 mM veratryl alcohol reduced both mineralization rates and MnP levels, without affecting laccase levels. Lignin peroxidase activity was not detected under any condition. Addition of purified lignin peroxidase to the cultures in the presence or absence of veratryl alcohol did not enhance mineralization rates significantly.
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PMID:Extracellular Enzyme Production and Synthetic Lignin Mineralization by Ceriporiopsis subvermispora. 1634 55


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