Biodegradation Of Malachite Green Research Articles

Biological Decolorization and Degradation of Malachite Green by Pseudomonas sp. YB2: Process Optimization and Biodegradation Pathway.

A novel strain Pseudomonas sp. YB2, which was isolated from activated sludge, was studied for biological decolorization and degradation of malachite green (MG). The results show that this aerobic strain is an aerobic bacterium, which has relatively high salt tolerance and high antibiotic resistance. The optimal performance condition for both bacterial growth and decolorization of MG was at 25-35°C and pH 5.0-7.0. It could efficiently decolorize 90.40% MG at a high concentration up to 1500mg/L in 24h, and concentrations of MG lower than 1000mg/L could be completely decolorized in 12h. The intermediate products of MG were detected using gas chromatography-mass spectrometer, including leucomalachite green, 4,4'-bis(dimethylamino) benzophenone, 4-(dimethylamino) benzophenone, phenol, dimethylaniline. The possible degradation pathways of MG by strain YB2 were proposed. This strain might be potentially useful for biodegradation of MG in real environments.

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Biodegradation of Malachite Green by the Ligninolytic Fungus Aspergillus flavus

The azo class of synthetic dyes represents one of the most industrially used dyes as well as a major class of environmental contaminants, which possess one or more azo bonds (NN) along with aromatic rings and sulfonic groups. Due to its recalcitrant nature and toxicity for animals and human beings, the elimination of these dyes from the environment is essential. The present study focuses on the biodegradation of such azo dye, malachite green (MG), through a potent ligninolytic fungus, Aspergillus flavus (F10). A. flavus (F10) completely decolorized MG (150 mg L−1) within 6–8 days in optimized Kirk's basal medium under static aerobic conditions at pH 5.8. Sucrose and sodium nitrate were efficient carbon and nitrogen sources, respectively. The products obtained after degradation were examined using UV‐vis spectrophotometry, Fourier transform IR spectroscopy, and liquid chromatography‐mass spectroscopy. The metabolic intermediate products were identified as N‐demethylated and N‐oxidized metabolites, including primary and secondary arylamines, which confirms the involvement of laccase and manganese peroxidase in decolorization and degradation of MG. The end products of MG degradation were nontoxic. A. flavus (F10), immobilized by entrapment on natural and synthetic polymeric matrices was found to be a more efficient degrader of MG as compared to free cells.

Biodegradation of malachite green by a novel copper-tolerant Ochrobactrum pseudogrignonense strain GGUPV1 isolated from copper mine waste water

Malachite green (MG) is a triphenyl methane cationic dye which is used to color fabrics and is employed as food additive, food coloring agent and medical disinfectant. MG is found to be toxic to aquatic organisms, animals including humans. Copper is a commonly found metal in environment due to anthropogenic activities. Most of the microorganisms show sensitivity toward it. This adversely affects their growth and activity. In the present study, biodegradation of MG by a copper-tolerant bacterium has been investigated. Biodegradation was confirmed by UV–Vis and FTIR spectroscopy. The metabolites generated after degradation of MG were identified by LC/MS and a plausible pathway of MG degradation has been elucidated. Microbial and phyto toxicity of generated metabolites were also evaluated. A strain belonging to Ochrobactrum pseudogrignonense strain GGUPV1 was discovered from copper mine waste water. This bacterium could tolerate as high as 50 mM copper sulfate in minimal medium. It was observed that this bacterium could degrade 400 mg/L of MG in minimal medium. Decolorization of MG was also observed in presence of copper sulfate in the medium. Degradation of MG was confirmed by UV–Vis and FTIR spectroscopy. GC/MS study indicated that metabolites generated after degradation of MG were nontoxic to Staphylococcus aureus. This is the first report showing degradation of MG by Ochrobactrum pseudogrignonense. This strain can be successfully employed for degradation of MG.

Biodegradation of malachite green by Ochrobactrum sp.

This study presents the biodegradation of malachite green (MG), a triphenylmethane dye, using a novel microorganism isolated from textile effluent contaminated environment. The organism responsible for degradation was identified as Ochrobactrum sp JN214485 by 16S rRNA analysis. The effect of operating parameters such as temperature, pH, immobilized bead loading, and initial dye concentration on % degradation was studied, and their optimal values were found to be 30 °C, 6, 20 g/L and 100 mg/L, respectively. The analysis showed that the extracellular enzymes were responsible for the degradation. The biodegradation of MG was confirmed by UV-visible spectroscopic and FTIR analysis. The phytotoxicity test concluded that the degradation products were less toxic compared to MG. The kinetics of biodegradation was studied and the activation energy was found to be 10.65 kcal/mol.

Biological decolorization of malachite green by Deinococcus radiodurans R1

Cultures of Deinococcus radiodurans R1 were observed to decolorize malachite green (MG) dye. The effects of various factors on decolorization efficiency were investigated. The optimal decolorization temperature and pH ranges were 25-50°C and 6.0-8.0, respectively. With increasing initial MG concentration, the decolorization efficiency decreased, and the kinetic parameters, R(MG,max) and K(m) were 416.7 mg-MG/g-cell/h and 1033.7 mg/L, respectively. The D. radiodurans R1 cells were capable of tolerating and rapidly degrading high concentrations of the dye. When MG concentration was 200 mg/L, decolorization efficiency was up to 97.2% within 30 min. The intermediate products of MG biodegradation were 4-(dimethylamino)phenol and 4-(dimethylamino)benzophenone, as identified by gas chromatography/mass spectrometry analysis. Toxicity tests indicated that D. radiodurans R1 did not detoxify an MG solution completely, but clearly reduced its toxicity. This study demonstrated that this strain was an efficient degrader compared to other microorganisms.

A Possible Role of Aspergillus niger Mitochondrial Cytochrome c in Malachite Green Reduction Under Calcium Chloride Stress

In previous work, decolorization of malachite green (MG) was studied in Aspergillus niger in the presence and absence of calcium chloride stress. Decolorization took place within 24 h, and a signal transduction process that initiated MG decolorization was suggested to be involved. In the present study, further investigation of the relationship between calcium chloride stress and enhanced MG biodegradation was conducted at the sub-cellular level. MG-NADH reductase activity, a key enzyme in MG decolorization, was produced as decolorization commenced, and enzyme activity increased threefold upon exposure to calcium chloride. Inhibitors of cytochrome p450, Ca(2+) channel activity as well as activity of the signaling protein phosphoinositide 3-kinase were tested. All three activities were inhibited to different extents resulting in reduced MG decolorization. Spectral analysis of the mitochondrial fraction showed a heme signal at 405 nm and A405/A280 ratio that is characteristic of the porphoryin ring of cytochromes. There were no peaks detected for cytochromes a or b, but a shoulder appearing at 550 nm was observed, which suggested that cytochrome c is involved; the absorbance for cytochrome c doubled after calcium chloride stress supporting this idea. MG decolorization took place via a series of demethylation steps, and cytotoxicity analysis revealed a decrease in the toxicity associated with generation of leucomalachite green.

Biodegradation of Malachite Green by Klebsiella Terrigenaptcc 1650: The Critical Parameters Were Optimized Using Taguchi Optimization Method

In the work ahead, the microbial degradation of Malachite Green (MG) was investigated by the bacterium Klebsiella. At first, the Taguchi Optimizing Method (TOM) was used to optimize the experimental conditions. 16 introduced states were tested by the L-16 array type of the software and each case was repeated three times for calculating signal/noise (S/N) ratio. Based on S/N ratio, it was found that, the best experimental conditions will be at the dye concentration of (25 ppm), temperature (30°C), pH (~6), carbon source (Lactose) and nitrogen source (Ammonium nitrate). After reviewing the obtained results of Taguchi software, were found that, initial dye concentration and nitrogen source are most and less effective in the MG degradation experiments respectively. For experimental study, the MSM (Mineral Salt Medium) with phosphate buffers (for pH of 6, 6.6 and 7), Tris tampons (for pH of 6.7, 8 and 4.8) and acetic acid/sodium acetate tampons (for pH of 5 and 6.5) were used. For chemical analysis, dichloromethane was used as organic solvent. Eventually, UV-Visible absorption spectrum, HPLC and FTIR analysis confirmed completely degradation of MG by the bacterium Klebsiella.

Malachite green decolorization by non-basidiomycete filamentous fungi of Penicillium pinophilum and Myrothecium roridum

Fourteen of non-basidiomycete fungi isolated from biota contaminated with xenobiotics were investigated for their ability to decolorize a synthetic dye Malachite green (MG) during the growth on solid as well as in liquid Czapek-Dox (CzD) medium. Two strains of the highest efficiency of MG removal were identified by molecular techniques as Penicillium pinophilum and Myrothecium roridum and chosen for the more detailed study. Decolorization experiments accompanied by enzymes (laccase and MG reductase) assay and mycelium microscopic observations allow to propose patterns of MG removal by P. pinophilum and M. roridum. Strain of P. pinophilum decolorized MG by simultaneous biosorption with intracellular dye biotransformation accompanied by the 3-times increase activity of MG reductase. Removal of MG by M. roridum seemed to be mostly resulted from extracellular laccase activity (which was over 6 times higher in cells exposed to dye as compared to control mycelium). LC/MS/MS analyses of the intermediate compounds produced during decolorization of MG suggested that in both fungi biodegradation of MG involved reduction to leucomalachite green and conversion to N-demethylated metabolites.

Removal of malachite green from aqueous solution by immobilized Pseudomonas sp. DY1 with Aspergillus oryzae

Triphenylmethane dyes are considered to be one of the most recalcitrant pollutants in the environment. Malachite Green (MG) was successfully removed from aqueous solution by Pseudomonas sp. DY1 immobilization with Aspergillus oryzae. Inhibition test in the presence of sodium azide and nystatin indicated that A. oryzae was a natural immobilization reagent, and removal of MG by the immobilized cell pellets was attributed to the biodegradation by Pseudomonas sp. DY1. Optimum conditions of immobilization for maximum biodegradation were obtained using Taguchi design at 37 °C, inoculation size of Pseudomonas sp. DY1 (dry cell mass) 0.01 g, of A. oryzae (spore number) 1.0 × 10 9, initial pH 6.5. Decolorization and biodegradation of MG by immobilized pellets under optimum conditions were 99.5% and 93.3%, respectively. Immobilized pellets exhibited more than 96% decolorization after 16 days in batch condition, indicating it had stable and high biodegradation capabilities when immobilized for long-term operation.

Biodegradation of malachite green by Pseudomonas sp. strain DY1 under aerobic condition: characteristics, degradation products, enzyme analysis and phytotoxicity

Malachite green (MG), a widely-used and recalcitrant dye, has been confirmed to be carcinogenic and mutagenic against many organisms. The main objective of this study is to investigate the capability of Pseudomonas sp. strain DY1 to decolorize MG, and to explore the possible mechanism. The results showed that this strain demonstrated high decolorizing capability (90.3-97.2%) at high concentrations of MG (100-1,000 mg/l) under shaking condition within 24 h. In static conditions, lower but still effective decolorization (78.9-84.3%) was achieved. The optimal pH and temperature for the decolorization was pH 6.6 and 28-30°C, respectively. Mg(2+) and Mn(2+) (1 mM) were observed to significantly enhance the decolorization. The intermediates of the MG degradation under aerobic condition identified by UV-visible, GC-MS and LC-MS analysis included malachite green carbinol, (dimethyl amino-phenyl)-phenyl-methanone, N,N-dimethylaniline, (methyl amino-phenyl)-phenyl-methanone, (amino phenyl)-phenyl methanone and di-benzyl methane. The enzyme analysis indicated that Mn-peroxidase, NADH-DCIP and MG reductase were involved in the biodegradation of MG. Moreover, phytotoxicity of MG and detoxification for MG by the strain were observed. Therefore, this strain could be potentially used for bioremediation of MG.

Biodegradation of Malachite Green and Rhodamine B by Cecal Microflora of Rats

Bio-degradation of two non-permitted dyes namely Malachite green and Rhodamine B. commonly encountered in the food commodities, through rat caecal microflora was studied. Malachite green was biotransformed by caecal microflora to one fluorescent metabolite with a Rf value of 0.09. Incubation of Rhodamine B with caecal microflora resulted in two fluorescent metabolites with Rf values of 0.72 and 0.09. The D150 value of Malachite green was quite low (10 min). while that of Rhodamine B could not be derived as the maximum degradation was only 32%. The results suggest that Malachite green and Rhodamine B are biotransformed to different metabolites by rat caecal microflora which may help in delineating the mechanism of carcinogenic potential of these two dyes.