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Enzyme
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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)
The process parameters influencing the production of extracellular laccases by Streptomyces psammoticus MTCC 7334 were optimized in submerged fermentation. Coffee pulp and yeast extract were the best substrate and
nitrogen
source respectively for
laccase
production by this strain. The optimization studies revealed that the
laccase
yield was maximum at pH 7.5 and temperature 32 degrees C. Salinity of the medium was also observed to be influencing the enzyme production. An agitation rate of 175 rpm and 15% inoculum were the other optimized conditions for maximum
laccase
yield (5.9 U/mL). Pyrogallol and para-anisidine proved to be the best inducers for
laccase
production by this strain and the enzyme yield was enhanced by 50% with these inducers. S. psammoticus was able to decolourize various industrial dyes at different rates and 80% decolourization of Remazol Brilliant Blue R (RBBR) was observed after 10 days of incubation in dye based medium.
...
PMID:Effect of inducers and process parameters on laccase production by Streptomyces psammoticus and its application in dye decolourization. 1776 39
The white-rot basidiomycete Physisporinus rivulosus strain T241i is highly selective for degradation of softwood lignin, which makes this fungus suitable for biopulping. In order to promote
laccase
production, P. rivulosus was cultivated in nutrient-
nitrogen
sufficient liquid media containing either charcoal or spruce sawdust as supplements. Two laccases with distinct pI values, Lac-3.5 and Lac-4.8, were purified from peptone-spruce sawdust-charcoal cultures of P. rivulosus. Both laccases showed thermal stability at up to 60 degrees C. Lac-4.8 was thermally activated at 50 degrees C. Surprisingly, both laccases displayed atypically low pH optima (pH 3.0-3.5) in oxidation of the commonly used
laccase
substrates syringaldazine (4-hydroxy-3,5-dimethoxybenzaldehyde azine), 2,6-dimethoxyphenol and guaiacol (2-methoxyphenol). Steady-state kinetic measurements pointed to unusually low affinity to guaiacol at low pH, whereas the kinetic constants for the methoxyphenols and ABTS were within the ranges reported for other fungal laccases. The combination of thermotolerance with low pH optima for methoxylated phenol substrates suggests that the two P. rivulosus T241i laccases possess potential for use in biotechnological applications.
...
PMID:Novel thermotolerant laccases produced by the white-rot fungus Physisporinus rivulosus. 1780 27
Laccase production by solid-state fermentation (SSF) using an indigenously isolated white rot basidiomycete Ganoderma sp. was studied. Among the various agricultural wastes tested, wheat bran was found to be the best substrate for
laccase
production. Solid-state fermentation parameters such as optimum substrate, initial moisture content, and inoculum size were optimized using the one-factor-at-a-time method. A maximum
laccase
yield of 2,400 U/g dry substrate (U/gds) was obtained using wheat bran as substrate with 70% initial moisture content at 25 degrees C and the seven agar plugs as the inoculum. Further enhancement in
laccase
production was achieved by supplementing the solid-state medium with additional carbon and
nitrogen
source such as starch and yeast extract. This medium was optimized by response surface methodology, and a fourfold increase in
laccase
activity (10,050 U/g dry substrate) was achieved. Thus, the indigenous isolate seems to be a potential
laccase
producer using SSF. The process also promises economic utilization and value addition of agro-residues.
...
PMID:Solid-state fermentation for enhanced production of laccase using indigenously isolated Ganoderma sp. 1802 93
Biodegradation of endocrine-disrupting bisphenol A was investigated with several white rot fungi (Irpex lacteus, Trametes versicolor, Ganoderma lucidum, Polyporellus brumalis, Pleurotus eryngii, Schizophyllum commune) isolated in Korea and two transformants of T versicolor (strains MrP 1 and MrP 13). I. lacteus degraded 99.4% of 50 mg/l bisphenol A in 3 h incubation and 100% in 12 h incubation. which was the highest degradation rate among the fungal strains tested. T. versicolor degraded 98.2% of 50 mg/l bisphenol A in 12 h incubation. Unexpectedly, the transformant of the Mn-repressed peroxidase gene of T. versicolor, strain MrP 1, degraded 76.5% of 50 mg/l bisphenol A in 12 h incubation, which was a lower degradation rate than wild-type T. versicolor. The removal of bisphenol A by I. lacteus occurred mainly by biodegradation rather than adsorption. Optimum carbon sources for biodegradation of bisphenol A by I. lacteus were glucose and starch, and optimum
nitrogen
sources were yeast extract and tryptone in a minimal salts medium; however, bisphenol A degradation was higher in nutrient-rich YMG medium than that in a minimal salts medium. The initial degradation of endocrine disruptors was accompanied by the activities of manganese peroxidase and
laccase
in the culture
...
PMID:Biodegradation of endocrine-disrupting bisphenol A by white rot fungus Irpex lacteus. 1805 26
The white rot fungus Trametes versicolor is an efficient lignin degrader with ecological significance and industrial applications. Lignin-modifying enzymes of white rot fungi are mainly produced during secondary metabolism triggered in these microorganisms by nutrient deprivation. Selective ubiquitin/proteasome-mediated proteolysis is known to play a crucial role in the response of cells to various stresses such as nutrient limitation, heat shock, and heavy metal exposure. Previous studies from our laboratory demonstrated that proteasomal degradation of intracellular proteins is involved in the regulation of
laccase
, a major ligninolytic enzyme of T. versicolor, in response to cadmium. In the present study, it was found that the 6-h
nitrogen
starvation leads to depletion of intracellular free ubiquitin pool in T. versicolor. The difference in the intracellular level of free monomeric ubiquitin observed between the mycelium extract from the
nitrogen
-deprived and that from the
nitrogen
-sufficient culture was accompanied by the different pattern of ubiquitin-dependent degradation. Furthermore, it was found that
nitrogen
deprivation affected 26S proteasome activities of T. versicolor. Proteasome inhibition by lactacystin beta-lactone, a highly specific agent, increased
laccase
activity in
nitrogen
-deprived cultures, but not in
nitrogen
-sufficient cultures. The present study implicates the ubiquitin/proteasome-mediated proteolytic pathway in the response of T. versicolor to
nitrogen
deprivation.
...
PMID:The role of the ubiquitin-proteasome system in the response of the ligninolytic fungus Trametes versicolor to nitrogen deprivation. 1827 47
In this study, we used functional genomic strategies, proteomics and quantitative real-time (qRT)-PCR, to advance our understanding of genes associated with fumonisin production in the fungus Fusarium verticillioides. Earlier studies have demonstrated that deletion of the FCC1 gene, which encodes a C-type cyclin, leads to a drastic reduction in fumonisin production and conidiation in the mutant strain (FT536). The premise of our research was that comparative analysis of F. verticillioides wild-type and FT536 proteomes will reveal putative proteins, and ultimately corresponding genes, that are important for fumonisin biosynthesis. We isolated proteins that were significantly upregulated in either the wild type or FT536 via two-dimensional polyacrylamide gel electrophoresis, and subsequently obtained sequences via mass spectrometry. Homologs of identified proteins, e.g., carboxypeptidase,
laccase
, and
nitrogen
metabolite repression protein, are known to have functions involved in fungal secondary metabolism and development. We also identified gene sequences corresponding to the selected proteins and investigated their transcriptional profiles via quantitative real-time (qRT)-PCR in order to identify genes that show concomitant expression patterns during fumonisin biosynthesis. These genes can be selected as targets for functional analysis to further verify their roles in FB1 biosynthesis.
...
PMID:Identification of genes associated with fumonisin biosynthesis in Fusarium verticillioides via proteomics and quantitative real-time PCR. 1846 56
The objective of this study was to exploit the decolorization potential of a newly isolated white-rot fungus Schizophyllum commune IBL-6 for the biodegradation of reactive textile dye Cibacron Red FN-2BL. In the initial decolorization study of 10 days, it was observed that S. commune IBL-6 was a better decolorizer of Cibacron Red FN-2BL. Various process parameters like composition of basal nutrient medium, pH, temperature, additional carbon and
nitrogen
sources, and initial dyestuff concentration were optimized to develop an economic decolorization process. The optimum dye decolorization was achieved in basal nutrient medium II containing 0.1% Cibacron Red FN-2BL and supplemented with 1% glucose after 3 days incubation at pH 4.5 and 30 degrees C. All the additional carbon sources were found to enhance decolorization process, whereas most of the
nitrogen
supplements caused fungal-growth inhibition. The pattern of enzymes involved in the biodegradation of this dye was studied, and manganese peroxidase was found to be the major peroxidase with minor lignin peroxidase and
laccase
activities.
...
PMID:Optimization of culture conditions for enhanced decolorization of cibacron red FN-2BL by Schizophyllum commune IBL-6. 1850 May 86
The exploration of seven physiologically different white rot fungi potential to produce cellulase, xylanase,
laccase
, and manganese peroxidase (MnP) showed that the enzyme yield and their ratio in enzyme preparations significantly depends on the fungus species, lignocellulosic growth substrate, and cultivation method. The fruit residues were appropriate growth substrates for the production of hydrolytic enzymes and
laccase
. The highest endoglucanase (111 U ml(-1)) and xylanase (135 U ml(-1)) activities were revealed in submerged fermentation (SF) of banana peels by Pycnoporus coccineus. In the same cultivation conditions Cerrena maxima accumulated the highest level of
laccase
activity (7,620 U l(-1)). The lignified materials (wheat straw and tree leaves) appeared to be appropriate for the MnP secretion by majority basidiomycetes. With few exceptions, SF favored to hydrolases and
laccase
production by fungi tested whereas SSF was appropriate for the MnP accumulation. Thus, the Coriolopsis polyzona hydrolases activity increased more than threefold, while
laccase
yield increased 15-fold when tree leaves were undergone to SF instead SSF. The supplementation of
nitrogen
to the control medium seemed to have a negative effect on all enzyme production in SSF of wheat straw and tree leaves by Pleurotus ostreatus. In SF peptone and ammonium containing salts significantly increased C. polyzona and Trametes versicolor hydrolases and
laccase
yields. However, in most cases the supplementation of media with additional
nitrogen
lowered the fungi specific enzyme activities. Especially strong repression of T. versicolor MnP production was revealed.
...
PMID:Effect of growth substrate, method of fermentation, and nitrogen source on lignocellulose-degrading enzymes production by white-rot basidiomycetes. 1871 10
The decolourizing ability of Aspergillus alliaceus 121C was investigated on solid medium. The effects of
nitrogen
(N), carbon (C) sources and supplements on the decolourization of Indigo and Congo red dyes were studied. It has been shown that both the nature and the quantity of available N- and C-sources exert an influence on growth and decolourization. For the six N-sources (NH(4)Cl, Diammonium Tartrate, urea, malt extract, peptone and yeast extract) tested for Congo red decolourization, 8mM yeast extract provided the higher decolourized zone diameter (80 mm) and colony diameter (80 mm). 12 mM urea provided the higher decolourized zone diameter (76+/-2mm) and colony diameter (80 mm) for Indigo decolourization. For the C-sources tested (glucose, starch, glycerol and lactose), above 12.5mM of glucose and 62.5mM of starch provided the higher decolourized zones diameters of 80 mm and 77+/-3mm for Indigo and Congo red, respectively. When the fungi was grown in liquid medium containing optimum carbon and
nitrogen
sources supplemented with oak sawdust and wheat bran, more than 98.6% and 98% of colour removal are obtained for Indigo and Congo red dyes, respectively. The detection of ligninolytic enzymes proved that
laccase
and lignine-peroxidase (LiP) are the two enzymes responsible of the decolourization of the two dyes.
...
PMID:Effect of nitrogen and carbon sources on Indigo and Congo red decolourization by Aspergillus alliaceus strain 121C. 1875 34
Some conditions in media composition for laccases production, such as different sources of carbon and organic
nitrogen
, antifoams and a surfactant, were studied in liquid cultures of Pleurotus sajor-caju strain PS-2001. Cultivation with fructose or glucose as carbon sources produced maximum enzyme activities of 37 and 36 U mL(-1), respectively. When sucrose was present in the medium, the best results were obtained using 5 g L(-1) of this carbohydrate, on the 11th day of the process, attaining
laccase
titres of 13 U mL(-1). In a medium without casein, practically no enzyme was produced during the experiments; among the sources of
nitrogen
studied, pure casein led to the highest titres of
laccase
activity. Different concentrations of pure casein and sucrose were also tested. As to the different concentrations of casein, the addition of 1.5 g L(-1) resulted in the highest titres of
laccase
activity. Negligible levels of manganese peroxidase activity were also detected in the culture medium. In low concentrations, polypropylene glycol or silicon-based antifoams and the surfactant Tween 80 have no significant influence on the formation of laccases by P. sajor-caju. However, enhanced concentration of polypropylene glycol negatively affected the production of laccases but favored the titres in total peroxidases, lignin peroxidase and veratryl alcohol oxidase.
...
PMID:Production of laccases in submerged process by Pleurotus sajor-caju PS-2001 in relation to carbon and organic nitrogen sources, antifoams and Tween 80. 1875 36
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