Two Manganese Peroxidases and a Laccase of Trametes polyzona KU-RNW027 with Novel Properties for Dye and Pharmaceutical Product Degradation in Redox Mediator-Free System

Two manganese peroxidases (MnPs), MnP1 and MnP2, and a laccase, Lac1, were purified from Trametes polyzona KU-RNW027. Both MnPs showed high stability in organic solvents which triggered their activities. Metal ions activated both MnPs at certain concentrations. The two MnPs and Lac1, played important roles in dye degradation and pharmaceutical products deactivation in a redox mediator-free system. They completely degraded Remazol brilliant blue (25 mg/L) in 10–30 min and showed high degradation activities to Remazol navy blue and Remazol brilliant yellow, while Lac1 could remove 75% of Remazol red. These three purified enzymes effectively deactivated tetracycline, doxycycline, amoxicillin, and ciprofloxacin. Optimal reaction conditions were 50 °C and pH 4.5. The two MnPs were activated by organic solvents and metal ions, indicating the efficacy of using T. polyzona KU-RNW027 for bioremediation of aromatic compounds in environments polluted with organic solvents and metal ions with no need for redox mediator supplements.

Combined strategies for improving production of a thermo-alkali stable laccase in Pichia pastoris

Background: Laccases are copper-containing enzymes which have been used as green biocatalysts for many industrial processes. Although bacterial laccases have high stabilities which facilitate their application under harsh conditions, their activities and production yields are usually very low. In this work, we attempt to use a combinatorial strategy, including site-directed mutagenesis, codon and cultivation optimization, for improving the productivity of a thermo-alkali stable bacterial laccase in Pichia pastoris. Results: A D500G mutant of Bacillus licheniformis LS04 laccase, which was constructed by site-directed mutagenesis, demonstrated 2.1-fold higher activity when expressed in P. pastoris. The D500G variant retained similar catalytic characteristics to the wild-type laccase, and could efficiently decolorize synthetic dyes at alkaline conditions. Various cultivation factors such as medium components, pH and temperature were investigated for their effects on laccase expression. After cultivation optimization, a laccase activity of 347 ± 7 U/L was finally achieved for D500G after 3 d of induction, which was about 9.3 times higher than that of wild-type enzyme. The protein yield under the optimized conditions was about 59 mg/L for D500G. Conclusions: The productivity of the thermo-alkali stable laccase from B. licheniformis expressed in P. pastoris was significantly improved through the combination of site-directed mutagenesis and optimization of the cultivation process. The mutant enzyme retains good stability under high temperature and alkaline conditions, and is a good candidate for industrial application in dye decolorization.

Effect of laccase from Hypsizygus ulmarius in decolorization of different dyes.

The objective of the study was to check the laccase (purified from Hypsizygus ulmarius) for decolorization of different dyes. The purified laccase from Hypsizygus ulmarius was studied for its decolorization of different dyes (Remazol brilliant blue R (RBBR), Alizarin red, Congo red, methyl orange and methyl violet). The results indicated that the percent of decolorization was increased when the time course and enzyme concentration was increased. The purified laccase showed maximum amount of decolorization in RBBR (85%) and followed by Methyl Orange (75%), Alizarin Red (73%), Methyl Violet (72%) and Congo Red (69%) without any additional redox mediator which suggest that this enzyme could be used in industries for effluent treatment.

Heterologous Expression of Phanerochaete chrysoporium Glyoxal Oxidase and its Application for the Coupled Reaction with Manganese Peroxidase to Decolorize Malachite Green

cDNA of the glx1 gene encoding glyoxal oxidase (GLX) from Phanerochaete chrysosporium was isolated and expressed in Pichia pastoris. The recombinant GLX (rGLX) produces H2O2 over 7.0 nmol/min/mL using methyl glyoxal as a substrate. Use of rGLX as a generator of H2O2 improved the coupled reaction with recombinant manganese peroxidase resulting in decolorization of malachite green up to 150 microM within 90 min.

The Decolorizing Characterization of Shewanella decolorationis S12~T / 微生物学通报

High efficient dyes decolorizing bacterium, strain S12~T, was isolated from activated-sludge of textile-printing wastewater treatment plant. The strain was identified as a novel specie of the genus Shewanella, for which the name Shewanella decolorationis sp. nov. is proposed. It's decolorizing rate reached 96% in 4h, when 50mg/L of azo dye was used. The organism exhibited a remarkable color removal capability, even at azo dye's concentration of 2,000mg/L. A clear decolorizing zone around each colonies appeared after four days grown on LB plate containing 500mg/L azo dye. The changes of UV-visible spectra of azo dye solution indicate that the color removal was largely attributed to biodegradation. The decolorizing enzymes of strain S12~T were constitute type and not secreted to the culture medium.

Isolation and Characteristic of an Azo Dye-decolorizing Salt-tolerant Bacteria Strain GYW / 微生物学通报

A salt-tolerant strain GYW capable of decolorating azo dye was isolated and identified as Halo-monas sp.by 16S rDNA.The result showed that the decolorizing salt-tolerant bacteria could survive above the 10% salt concentration and it could decolorize many dyes.The strain had a high decolorizing rate on acid red GR under the condition of pH 7.5,anaerobic 30?C and 10% NaCl.The ion of Cl- strong inhibited the decolorization of acid red GR,and the ion of SO42- affected little on the decolorization,and the lycine addi-tion with the optimal concentration of 200 mg/L could enhanced the decolorization rate under high NaCl concentration.