A simple strategy for extracellular production of CotA laccase in Escherichia coli and decolorization of simulated textile effluent by recombinant laccase

Abstract

Laccases are green oxidases with a number of potential industrial applications. In this study, recombinant Bacillus subtilis CotA laccase was secreted by Escherichia coli via both the α-hemolysin secretion system and the YebF secretion system after microaerobic induction. Meanwhile, we discovered a much simpler approach for extracellular production of recombinant CotA laccase from E. coli, involving alternation of induction conditions to release recombinant CotA following intracellular expression. By optimizing the induction parameters, the extracellular yield of recombinant CotA laccase was improved from 157.4 to 2401.3 U/L after 24 h of induction. This strategy could be suitable for large-scale production of CotA laccase for industrial use. Recombinant CotA laccase was purified by Ni affinity chromatography in a single step and showed similar biochemical properties to wild-type laccase. Purified as well as crude recombinant CotA laccase efficiently decolorized seven structurally different dyes. The decolorization capability of recombinant CotA laccase under harsh conditions was investigated by incubation of the enzyme with a simulated textile effluent (STE) with pH 11.6, 3.5 % salinity and peak absorbance of 10.42. Recombinant CotA laccase efficiently decolorized 77.0 % of STE after 48 h reaction, demonstrating the potential of this enzyme for industrial dye effluent treatment.

Pilot scale production of extracellular thermo‐alkali stable laccase from Pseudomonas sp. S2 using agro waste and its application in organophosphorous pesticides degradation

“…The half‐life of S2LAC at 90 °C was 90 min. The thermostability of S2LAC is higher than other documented laccase, but laccase from Bacillus tequilensis SN4 retained 100% of its activity at 65 °C after 24 h of incubation and Bacillus Subtilis WD23 retained 50% activity after incubation at 60 °C for 68 h . The thermostability of S2LAC is comparably greater than available laccase .…”

Efficient secretion of three fungal laccases from Saccharomyces cerevisiae and their potential for decolorization of textile industry effluent—A comparative study

“…Although decolorization of individual synthetic dyes has been investigated frequently, only few studies on real textile wastewater or simulated textile effluent (STE) treatment by laccases have been performed. Textile industrial wastewater is very difficult to treat as it contains high concentrations of dye mixtures with usually synthetic origin and complex structures, it has very high levels of pH and salinity, and often contains also metal ions and organic solvents .…”

“…Textile industrial wastewater is very difficult to treat as it contains high concentrations of dye mixtures with usually synthetic origin and complex structures, it has very high levels of pH and salinity, and often contains also metal ions and organic solvents . Despite very hard environment for most organisms and biocatalysts, several studies have recently focused on biological wastewater treatment, inter alia, also with the use of laccase‐producing fungi or fungal and bacterial laccases . In most of these studies, WW or STE were required to be additionally buffered to acidic pH, which is needed for fungal laccases, but this is inconvenient and expensive, especially for large‐scale treatment.…”

“…[69][70][71] Despite very hard environment for most organisms and biocatalysts, several studies have recently focused on biological wastewater treatment, inter alia, also with the use of laccase-producing fungi 65,67 or fungal 49,64,68 and bacterial laccases. 64,66 In most of these studies, WW or STE were required to be additionally buffered to acidic pH, which is needed for fungal laccases, but this is inconvenient and expensive, especially for large-scale treatment. In this work, no buffering was necessary because pH of the final reaction mixture containing WW (pH 11.2) and crude laccases was 4.6, probably due to a strong buffering capacity of the culture supernatant.…”

Improving the Indigo Carmine Decolorization Ability of a Bacillus amyloliquefaciens Laccase by Site-Directed Mutagenesis

“…Unfortunately, the secretory expression of bacterial laccases in P. pastoris were unsatisfactory due to the low yield and long cultivation time [11,20,21]. Recently, the B. subtilis laccase was successfully expressed in secretory form in E. coli by altering the induction conditions, and high laccase activity (2401 U·L −1 ) was achieved after the optimization of induction parameters [22]. In the present study, we also detected high activity in the culture medium for both the wild-type and D501G laccase using the two phase induction strategy.…”