“…The laccases produced by all the fungi exhibited maximum activity at pH 3.0-3.5 and stability in acidic to alkaline pH. It is common for basidiomycetes laccases pH optima in the acidic range, although they are more stable at neutral to alkaline pH values (23,27,34). pH optimum for MnP and LiP activities were variable in function of the strains producer with optimum values between 4.5 to 6.0 for enzymes from C. byrsina and Ph.…”
Wood rotting Basidiomycetes collected in the “Estação Ecológica do Noroeste Paulista”, São José do Rio Preto, São Paulo State, Brazil, concerning Aphyllophorales order and identified as Coriolopsis byrsina SXS16, Lentinus strigellus SXS355, Lentinus sp SXS48, Picnoporus sanguineus SXS 43 and Phellinus rimosus SXS47 were tested for ligninases production by solid state fermentation (SSF) using wheat bran or rice straw as culture media. C. byrsina produced the highest laccase (200 U mL-1) and Lentinus sp produced the highest activities of manganese peroxidase (MnP) and lignin peroxidase (LiP) (7 and 8 U mL-1, respectively), when cultivated on wheat bran. The effect of N addition on enzyme production was studied in medium containing rice straw and the data showed an increase of 3 up to 4-fold in the laccase production compared to that obtained in SSF on wheat bran. The laccases presented optimum pH at 3.0-3.5 and were stable at neutral pH values. Optimum pH for MnP and LiP activities was at 3.5 and between 4.5 and 6.0, respectively. All the strains produced laccase with optimum activities between 55-60ºC while the peroxidases presented maximum activity at temperatures of 30 to 55ºC. The crude enzymes promoted decolorization of chemically different dyes with around 70% of decolorization of RBBR and cybacron blue 3GA in 6h of treatment. The data indicated that enzymes from these basidiomycetes strains are able to decolorize synthetic dyes.
“…The laccases produced by all the fungi exhibited maximum activity at pH 3.0-3.5 and stability in acidic to alkaline pH. It is common for basidiomycetes laccases pH optima in the acidic range, although they are more stable at neutral to alkaline pH values (23,27,34). pH optimum for MnP and LiP activities were variable in function of the strains producer with optimum values between 4.5 to 6.0 for enzymes from C. byrsina and Ph.…”
Wood rotting Basidiomycetes collected in the “Estação Ecológica do Noroeste Paulista”, São José do Rio Preto, São Paulo State, Brazil, concerning Aphyllophorales order and identified as Coriolopsis byrsina SXS16, Lentinus strigellus SXS355, Lentinus sp SXS48, Picnoporus sanguineus SXS 43 and Phellinus rimosus SXS47 were tested for ligninases production by solid state fermentation (SSF) using wheat bran or rice straw as culture media. C. byrsina produced the highest laccase (200 U mL-1) and Lentinus sp produced the highest activities of manganese peroxidase (MnP) and lignin peroxidase (LiP) (7 and 8 U mL-1, respectively), when cultivated on wheat bran. The effect of N addition on enzyme production was studied in medium containing rice straw and the data showed an increase of 3 up to 4-fold in the laccase production compared to that obtained in SSF on wheat bran. The laccases presented optimum pH at 3.0-3.5 and were stable at neutral pH values. Optimum pH for MnP and LiP activities was at 3.5 and between 4.5 and 6.0, respectively. All the strains produced laccase with optimum activities between 55-60ºC while the peroxidases presented maximum activity at temperatures of 30 to 55ºC. The crude enzymes promoted decolorization of chemically different dyes with around 70% of decolorization of RBBR and cybacron blue 3GA in 6h of treatment. The data indicated that enzymes from these basidiomycetes strains are able to decolorize synthetic dyes.
“…4). Although pH optima may also depend on the substrate used [5], most laccases in other fungi also have an optimum pH of around 3 with ABTS as a substrate [13], [6], [14], [16], [7].Figure 4Laccase activity at different pH values. This figure is for pH optima of enzyme.…”
The present study describes isolation of laccase producing fungal strain and optimization of the process parameters by design of experiment (DOE) technique to achieve the maximum production of extracellular laccases by Aspergillus flavus obtained from natural habitat. Bromophenol blue dye and ABTS (2,2 0 -azinobis 3-ethyl-benzothiazoline-6-sulfonate) were used as substrates for the screening of laccase activity. Design expert 8.0.7.1 software was used to optimize culture conditions such as carbon source, nitrogen source, temperature and pH. Subsequently, optimization for inoculums size was also carried out. The optimization studies revealed that the laccase yield was highest when operated at the following conditions: carbon source -cellulose (8%), nitrogen source -peptone (2%), temperature -35°C, pH -7 and inoculum of size 1.5 cm.
“…Therefore, change in pH, caused by the hydrolytic reaction biocatalyzed by esterase, activates the reaction of laccase (0.5 U•mL -1 equal to 3.78×10 -4 mM based on the average molecular weight of 66 kDa for fungal laccases [54][55][56][57] ) which catalyzes the oxidation of 1 mM ferrocyanide in the presence of oxygen. The schematic illustration of the composition of the OR gate is represented in Scheme 1 (see page 17).…”
Section: Composition and Mapping Of The Or Gate With Double Sigmoid F...mentioning
The first realization of a biomolecular OR gate function with double-sigmoid response (sigmoid in both inputs) is reported. Two chemical inputs activate the enzymatic gate processes resulting in the output signal: chromogen oxidation, which occurs when either one of the inputs or both are present (corresponding to the OR binary function), and can be optically detected.High-quality gate functioning in handling of sources of noise is enabled by "filtering" involving pH control with an added buffer. The resulting gate response is sigmoid in both inputs when proper system parameters are chosen, and the gate properties are theoretically analyzed within a model devised to evaluate its noise-handling properties.
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