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Biodegradation of triphenylmethane dye malachite green by a newly isolated fungus strain

Arunprasath, T., Sudalai, S., Meenatchi, R., Jeyavishnu, K., Arumugam, A.
Biocatalysis and agricultural biotechnology 2019 v.17 pp. 672-679
Fourier transform infrared spectroscopy, Lasiodiplodia, X-ray diffraction, adsorption, adverse effects, alkanes, alkenes, amides, biodegradation, carboxylic acids, decolorization, fungi, industrial effluents, laccase, malachite green, mineralization, mutagens, mycelium, oxidation, pH, temperature, textile industry, toxicity, xenobiotics
Malachite green (MG) is a synthetic cationic dye widely used in the textile industry as a coloring agent. It is reported to be a potential carcinogenic and mutagenic agent for the living organisms in nature. Hence, it is essential to treat and release the industrial effluents containing MG to avoid serious and irreversible effects to both the natural environment and living organisms. An effective method for mitigating the effects of toxic industrial dye is by utilizing microorganism to degrade it to non-hazardous compounds. Lasiodiplodia sp is a novel fungus species isolated from biota containing a high concentration of xenobiotics. It exhibits the ability to degrade malachite green in a wide range of temperatures (20 °C - 45 °C) and pH (3–12). The maximal degradation of MG was found to be 96.9% given the dye concentration of 50 mg/L, pH of 7 and temperature of 30 °C. The maximum rate of dye degradation was determined using Hanes–Woolf plot and found to be 123.5 mg-MG/g-cell/h. FTIR analysis endorses the conversion of MG into aromatic amides, carboxylic acids, alkenes and alkane suggesting that decolorization is occurred through oxidation of dyes by the action of laccases. X-ray diffraction analysis indicated that degradation was established by the process of bio adsorption and mineralization of dye in fungi mycelium. Chemical stability test on fungi mycelium indicated that the newly isolated species confer stability under adverse reaction conditions.