Homologous cloning, expression, and characterisation of a laccase from Streptomyces coelicolor and enzymatic decolourisation of an indigo dye

Abstract

The lack of a commercially available robust and inexpensive laccase is a major barrier to the widespread application of this enzyme in various industrial sectors. By using an efficient system developed in Streptomyces lividans, we have produced by homologous expression 350 mg L(-1) of a bacterial laccase with a high purity and without any extensive purification. This is the highest production yield reported in the literature for a bacterial laccase. The secreted enzyme achieved oxidation under a wide pH range depending on the substrate: 4.0 for 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) and 9.0 for 2,6-dimethoxyphenol. Furthermore, this bacterial laccase was found to be quite resistant under various conditions. It withstands pH from 3.0 to 9.0, shows a great thermostability at 70 degrees C and was highly resistant toward conventional inhibitors. For instance, while the laccase of Trametes versicolor was completely inhibited by 1 mM NaN(3), the laccase of Streptomyces coelicolor was fully active under the same conditions. To assess application potential of this laccase, we have investigated its ability to decolourise Indigo carmine. This enzyme was able to rapidly decolourise the dye in the presence of syringaldehyde as a redox mediator.

Heterologous expression and characterization of a high redox potential laccase from Coriolopsis polyzona MUCL 38443

“…The optimal temperature was found as 70 °C. On the other hand, at 30 °C, the enzyme was stable for more than a week and its half-life was longer than 8 h. The K m , V max , k cat , and k cat K m -1 values of the recombinant laccase were identified as 0.137 mM, 288.6 µmol min -1 L (Bento et al, 2005) and Streptomyces lividans (Dubé et al, 2008)], and plants [Arabidopsis thaliana (Wang et al, 2004) and Oryza sativa (de Wilde et al, 2008)]. Among those organisms, yeasts are usually more attractive hosts for heterologous protein production because of their faster microbial growth and ease of gene manipulation, along with the ability to perform posttranslational modifications.…”

Bacterial diversity and composition in major fresh produce growing soils affected by physiochemical properties and geographic locations

“…Relatively few bacterial laccases have been studied with respect to their ability to degrade azo dyes (Pereira et al, 2009;Singh et al, 2007). However, laccases produced by Streptomyces are reported to be effective for the decolorization of textile dyes (Dube et al, 2008;Lu et al, 2013;Molina-Guijarro et al, 2009). Gottlieb et al (2003) demonstrated the usefulness of a laccase enzyme produced by Streptomyces cyaneus CECT 3335.…”

Heterologous laccase production and its role in industrial applications

“…33 On the other hand, recombinant production of Streptomyces coelicolor laccase (SLAC) in Streptomyces lividans has yielded considerable large amount of laccase (350 mg l -1 ) with high purity. 34 The laccase from the ligninolytic fungus Cyathus bulleri has been just recently expressed in E. coli making it the first fungal laccase to be expressed in a bacterial host. 35 A collection of references on recombinant expression of laccases in bacterial hosts is available in Table 1.…”