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A novel multicopper oxidase (laccase) from cyanobacteria: Purification, characterization with potential in the decolorization of anthraquinonic dye

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ABSTRACT

A novel extracellular laccase enzyme produced from Spirulina platensis CFTRI was purified by ultrafiltration, cold acetone precipitation, anion exchange and size exclusion chromatography with 51.5% recovery and 5.8 purification fold. The purified laccase was a monomeric protein with molecular mass of ~66 kDa that was confirmed by zymogram analysis and peptide mass fingerprinting. The optimum pH and temperature of the enzyme activity was found at 3.0 and 30°C using ABTS as substrate but the enzyme was quite stable at high temperature and alkaline pH. The laccase activity was enhanced by Cu+2, Zn+2 and Mn+2. In addition, the dye decolorization potential of purified laccase was much higher in terms of extent as well as time. The purified laccase decolorized (96%) of anthraquinonic dye Reactive blue- 4 within 4 h and its biodegradation studies was monitored by UV visible spectra, FTIR and HPLC which concluded that cyanobacterial laccase can be efficiently used to decolorize synthetic dye and help in waste water treatment.

No MeSH data available.


Effect of pH on (a) laccase activity (b) laccase stability. Residual activity was measured using ABTS substrates. Values are mean of triplicates ± S.E
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pone.0175144.g003: Effect of pH on (a) laccase activity (b) laccase stability. Residual activity was measured using ABTS substrates. Values are mean of triplicates ± S.E

Mentions: The optimum pH of the purified laccase from Spirulina platensis CFTRI, Mysore was ~3.0 with ABTS substrate (Fig 3A). Similar pH was reported for laccase isolated Pleurotus sp, Pycnoporus sanguineus, Ganoderma lucidum, Pycnoporus sp [34, 35]. It was completed inactivated at pH-11 which might be due to the binding of a hydroxide anion to the trinuclear coppers of laccase that interrupts the internal electron transfer from T1 to trinuclear centre and ionization of pI [36]. It was reported that the oxidation rate of different substrate gradually decreased at higher pH that might be due to ionization of critical amino acids (Asp and Glu) [37]. The pH stability of laccase was determined and it retained 100% activity after 1 h at ~pH 8.0 and found to be most stable at this pH (Fig 3B). Similar results were obtained with laccase of Peniophora sp,Cerrena unicolor strain 137, γ-proteobacterium JB and Carica papaya [38–41].


A novel multicopper oxidase (laccase) from cyanobacteria: Purification, characterization with potential in the decolorization of anthraquinonic dye
Effect of pH on (a) laccase activity (b) laccase stability. Residual activity was measured using ABTS substrates. Values are mean of triplicates ± S.E
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383238&req=5

pone.0175144.g003: Effect of pH on (a) laccase activity (b) laccase stability. Residual activity was measured using ABTS substrates. Values are mean of triplicates ± S.E
Mentions: The optimum pH of the purified laccase from Spirulina platensis CFTRI, Mysore was ~3.0 with ABTS substrate (Fig 3A). Similar pH was reported for laccase isolated Pleurotus sp, Pycnoporus sanguineus, Ganoderma lucidum, Pycnoporus sp [34, 35]. It was completed inactivated at pH-11 which might be due to the binding of a hydroxide anion to the trinuclear coppers of laccase that interrupts the internal electron transfer from T1 to trinuclear centre and ionization of pI [36]. It was reported that the oxidation rate of different substrate gradually decreased at higher pH that might be due to ionization of critical amino acids (Asp and Glu) [37]. The pH stability of laccase was determined and it retained 100% activity after 1 h at ~pH 8.0 and found to be most stable at this pH (Fig 3B). Similar results were obtained with laccase of Peniophora sp,Cerrena unicolor strain 137, γ-proteobacterium JB and Carica papaya [38–41].

View Article: PubMed Central - PubMed

ABSTRACT

A novel extracellular laccase enzyme produced from Spirulina platensis CFTRI was purified by ultrafiltration, cold acetone precipitation, anion exchange and size exclusion chromatography with 51.5% recovery and 5.8 purification fold. The purified laccase was a monomeric protein with molecular mass of ~66 kDa that was confirmed by zymogram analysis and peptide mass fingerprinting. The optimum pH and temperature of the enzyme activity was found at 3.0 and 30°C using ABTS as substrate but the enzyme was quite stable at high temperature and alkaline pH. The laccase activity was enhanced by Cu+2, Zn+2 and Mn+2. In addition, the dye decolorization potential of purified laccase was much higher in terms of extent as well as time. The purified laccase decolorized (96%) of anthraquinonic dye Reactive blue- 4 within 4 h and its biodegradation studies was monitored by UV visible spectra, FTIR and HPLC which concluded that cyanobacterial laccase can be efficiently used to decolorize synthetic dye and help in waste water treatment.

No MeSH data available.