Biodegradation of synthetic textile dyes in waste water by some yeasts
Doaa Saber Abdel Maksoud El faramawy;
Abstract
The present study was conducted to investigate the decolorization and degradation of methyl red, reactive brilliant blue and malachite green dyes using yeast that isolated from the effluent treatment of the textile industries and some identified yeast strains under the optimum environmental conditions using the standard methods.
Among twenty-four yeast strains, 8 yeasts (33.3%), 5 yeasts
(20.8%) and 6 yeasts (25%) showed variable potential to decolorize methyl red, reactive brilliant blue and malachite green dyes, respectively. The most potent of degrading yeasts were Saccharomyces cerevisiae 43&44, Rhodotorula glutinis, Candida sphaerica, Candida utilis(1) and the three identified yeast isolates, Cryptococcus uniguttulatus, Rhodotorula rubra and Cryptococcus albidus.
All yeast strains were incubated for 12 h at 25º C for the decolorization of methyl red dye. Whereas, in case of reactive brilliant blue dye, all yeast strains were incubated for 18 h at 25ºC except for C. utilis(1) was at 37ºC. However, in case of malachite green dye, all yeast strains were incubated for 12 h except Rho. glutinis and Rho. rubra were for 18 h at 25ºC.
The pH of a medium varied between (3.5-6.5) among the selected yeast strains for the decolorization of the studied three dyes.
Some yeast strains showed high decolorization rate of dyes under static aerobic conditions and others under static anaerobic conditions.
The optimal inoculum size of all yeast strains to decolorize the three dyes was 40%.
The suitable cell concentrations for dye decolorization varied between 0.3-0.7 OD among the selected yeast strains.
High decolorization rate by all studied yeast strains was noticed at a concentration of 10 mg /l of methyl red and reactive brilliant blue dyes, and 1 mg /l of malachite green dye.
The studied yeast strains showed high decolorization rate of the three dyes, when they were grown in a medium contains glucose as the best carbon source. However, the best nitrogen source of the medium was yeast extract for methyl red and reactive brilliant blue dyes, and NaNO3 and NH4NO3 for malachite green dye.
The highest biodegradation of methyl red and reactive brilliant blue dyes by the selected yeast strains were confirmed by using plain distilled water, while in case of malachite green dye was confirmed by using distilled water supplemented with 5% glucose as a decolorization medium.
The yeast strain, C. sphaerica could achieved 78.94% decolorization rate of methyl red dye, while in case of reactive brilliant blue dye was 68.83% by C. sphaerica but in case of malachite green dye was 76.21% by S. cerevisiae (44).
A study of enzymes responsible for the biodegradation of the studied three dyes in control and the cells obtained after decolorization showed different levels of the activities of laccase, tyrosinase and lignin peroxidase. Laccase was the highly activated enzyme for the decolorization of these three dyes except C. utilis(1) followed by lignin peroxidase and tyrosinase enzymes. However, in the biodegradation of methyl red dye by
C. utilis(1), lignin peroxidase was highly activated then tyrosinase enzyme.
Fourier transform infrared spectroscopy (FTIR) spectrum of extracted metabolites of the studied three dyes showed significant changes in the chemical composition of the dyes after decolorization when compared with the control dye spectrum.
The products of the studied three dyes after decolorization were evaluated by phytotoxicity tests on germination of grains of Sorghum versicolor and seeds of Phaseolus vulgaris with compared to control. The results showed that the germination of the two plants were increased in the presence of the studied yeast strains.
Keywords:
Decolorization- Textile dyes- Azo dye- Anthraquinone dye- Triphenylmethane dye- Yeasts
Among twenty-four yeast strains, 8 yeasts (33.3%), 5 yeasts
(20.8%) and 6 yeasts (25%) showed variable potential to decolorize methyl red, reactive brilliant blue and malachite green dyes, respectively. The most potent of degrading yeasts were Saccharomyces cerevisiae 43&44, Rhodotorula glutinis, Candida sphaerica, Candida utilis(1) and the three identified yeast isolates, Cryptococcus uniguttulatus, Rhodotorula rubra and Cryptococcus albidus.
All yeast strains were incubated for 12 h at 25º C for the decolorization of methyl red dye. Whereas, in case of reactive brilliant blue dye, all yeast strains were incubated for 18 h at 25ºC except for C. utilis(1) was at 37ºC. However, in case of malachite green dye, all yeast strains were incubated for 12 h except Rho. glutinis and Rho. rubra were for 18 h at 25ºC.
The pH of a medium varied between (3.5-6.5) among the selected yeast strains for the decolorization of the studied three dyes.
Some yeast strains showed high decolorization rate of dyes under static aerobic conditions and others under static anaerobic conditions.
The optimal inoculum size of all yeast strains to decolorize the three dyes was 40%.
The suitable cell concentrations for dye decolorization varied between 0.3-0.7 OD among the selected yeast strains.
High decolorization rate by all studied yeast strains was noticed at a concentration of 10 mg /l of methyl red and reactive brilliant blue dyes, and 1 mg /l of malachite green dye.
The studied yeast strains showed high decolorization rate of the three dyes, when they were grown in a medium contains glucose as the best carbon source. However, the best nitrogen source of the medium was yeast extract for methyl red and reactive brilliant blue dyes, and NaNO3 and NH4NO3 for malachite green dye.
The highest biodegradation of methyl red and reactive brilliant blue dyes by the selected yeast strains were confirmed by using plain distilled water, while in case of malachite green dye was confirmed by using distilled water supplemented with 5% glucose as a decolorization medium.
The yeast strain, C. sphaerica could achieved 78.94% decolorization rate of methyl red dye, while in case of reactive brilliant blue dye was 68.83% by C. sphaerica but in case of malachite green dye was 76.21% by S. cerevisiae (44).
A study of enzymes responsible for the biodegradation of the studied three dyes in control and the cells obtained after decolorization showed different levels of the activities of laccase, tyrosinase and lignin peroxidase. Laccase was the highly activated enzyme for the decolorization of these three dyes except C. utilis(1) followed by lignin peroxidase and tyrosinase enzymes. However, in the biodegradation of methyl red dye by
C. utilis(1), lignin peroxidase was highly activated then tyrosinase enzyme.
Fourier transform infrared spectroscopy (FTIR) spectrum of extracted metabolites of the studied three dyes showed significant changes in the chemical composition of the dyes after decolorization when compared with the control dye spectrum.
The products of the studied three dyes after decolorization were evaluated by phytotoxicity tests on germination of grains of Sorghum versicolor and seeds of Phaseolus vulgaris with compared to control. The results showed that the germination of the two plants were increased in the presence of the studied yeast strains.
Keywords:
Decolorization- Textile dyes- Azo dye- Anthraquinone dye- Triphenylmethane dye- Yeasts
Other data
| Title | Biodegradation of synthetic textile dyes in waste water by some yeasts | Other Titles | التحلل الحیوى لصبغات النسیج الصناعیة فى میاه الصرف الصحى بواسطة بعض الخمائر | Authors | Doaa Saber Abdel Maksoud El faramawy | Issue Date | 2017 |
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