ABSTRACT
AIMS: The aim of this study was to evaluate the activity of a novel bacterial laccase-like multi-copper oxidase (LMCO) from Paenibacillus glucanolyticus SLM1: a bacterium isolated from pulp and paper waste. METHODS AND RESULTS: A new bacterial LMCO gene (CuOx) from P. glucanolyticus SLM1 was identified and cloned into pET22b. The protein it encodes was recombinantly expressed in Escherichia coli. The recombinant P. glucanolyticus LMCO had a molecular weight of approximately 90 kDa and demonstrated oxidation of the LMCO substrates 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS), catechol, and 2,6-Dimethoxyphenol (2,6-DMP), with the oxidation of ABTS occurring to the greatest extent (776 U mg-1 under optimal conditions of pH 7 and 40°C). Furthermore, recombinant P. glucanolyticus CuOx retained activity against ABTS in the presence of 1 mol l-1 NaCl, 50% dimethyl sulfoxide and 5% Tween-80 and can decolorize several types of dyes. CONCLUSIONS: This enzyme has a neutral pH optimum, is capable of decolorizing dyes, and is active in the presence salt, detergents and surfactant. The characteristics of this enzyme suggest that it could be used for a variety of industrial applications. SIGNIFICANCE AND IMPACT OF THE STUDY: This work characterizes a unique bacterial LMCO with activity higher than that of previously characterized fungal or bacterial LMCOs. This enzyme may have utility for industrial bleaching, treatment of dye effluent, and lignin removal.
Subject(s)
Oxidoreductases/metabolism , Paenibacillus/enzymology , Benzothiazoles/metabolism , Catechols/metabolism , Coloring Agents/metabolism , Hydrogen-Ion Concentration , Oxidoreductases/chemistry , Oxidoreductases/genetics , Oxidoreductases/isolation & purification , Pyrogallol/analogs & derivatives , Pyrogallol/metabolism , Recombinant Proteins/chemistry , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism , Sulfonic Acids/metabolismABSTRACT
Three isolates of bovine astrovirus, one from the United Kingdom and two from the United States, possessed common antigens by immunofluorescence and strain-specific antigens by neutralization and were designated as two, and probably three, distinct serotypes. The isolate US2, despite being a different serotype, possessed the same restrictive cell tropism and cytopathology as previously reported for isolate US1, of the M cells of the dome epithelium of the Peyer's patches. Serotyping of 16 field isolates indicated the presence of more undefined serotypes.
