Biodegradation of triphenylmethane dye Malachite Green by <Emphasis Type="Italic">Sphingomonas paucimobilis</Emphasis>

Triphenylmethane dyes belong to the most important group of synthetic colorants and are used extensively in the textile industries for dying cotton, wool, silk, nylon, etc. They are generally considered as the xenobiotic compounds, which are very recalcitrant to biodegradation. Sphingomonas paucimobilis, was isolated from the soil sample collected from contaminated sites of textile industry located in KsarHellal, Tunisia, and it was able to decolorize Malachite Green (MG) dye (50 mg/l) within 4 h under shaking condition (pH 9 and temperature 25°C). The effect of inoculum size, dye concentration, temperature and initial pH of the solution were studied. The results obtained from the batch experiments revealed the ability of the tested bacteria to remove dye. UV–Vis spectroscopy and FTIR analysis of samples before and after decolorization confirmed the ability of the tested strain to decolorize MG. In addition, the phytotoxicity study revealed the degradation of MG into non-toxic product by S. paucimobilis.     

Decolorization and biodegradation of reactive dyes and dye wastewater by a developed bacterial consortium

A bacterial consortium (consortium GR) consisting of Proteus vulgaris NCIM-2027 and Micrococcus glutamicus NCIM-2168 could rapidly decolorize and degrade commonly-used sulfonated reactive dye Green HE4BD and many other reactive dyes. Consortium GR shows markedly higher decolorization activity than that of the individual strains. The preferable physicochemical parameters were identified to achieve higher dye degradation and decolorization efficiency. The supplementation of cheap co-substrates (e.g., extracts of agricultural wastes) could enhance the decolorization performance of consortium GR. Extent of mineralization was determined with TOC and COD measurements, showing nearly complete mineralization of Green HE4BD by consortium GR (up to 90% TOC and COD reduction) within 24 h. Oxidoreductive enzymes seemed to be involved in fast decolorization/degradation process with the evidence of enzymes induction in the bacterial consortium. Phytotoxicity and microbial toxicity studies confirm that the biodegraded products of Green HE4BD by consortium GR are non-toxic. Consortium GR also shows significant biodegradation and decolorization activities for mixture of reactive dyes as well as the effluent from actual dye manufacturing industry. This confers the possibility of applying consortium GR for the treatment of industrial wastewaters containing dye pollutants.     

Decolorization and detoxification of Congo red and textile industry effluent by an isolated bacterium <Emphasis Type="Italic">Pseudomonas</Emphasis> sp. SU-EBT

The 16S rRNA sequence and biochemical characteristics revealed the isolated organism as Pseudomonas sp. SU-EBT. This strain showed 97 and 90% decolorization of a recalcitrant dye, Congo red (100 mg l⁻¹) and textile industry effluent with 50% reduction in COD within 12 and 60 h, respectively. The optimum pH and temperature for the decolorization was 8.0 and 40°C, respectively. Pseudomonas sp. SU-EBT was found to tolerate the dye concentration up to 1.0 g l⁻¹. Significant induction in the activity of intracellular laccase suggested its involvement in the decolorization of Congo red. The metabolites formed after decolorization of Congo red, such as p-dihydroxy biphenyl, 8-amino naphthol 3-sulfonic acid and 3-hydroperoxy 8-nitrosonaphthol were characterized using FTIR and GC–MS. Phytotoxicity study revealed nontoxic nature of the degradation metabolites to Sorghum bicolor, Vigna radiata, Lens culinaris and Oryza sativa plants as compared to Congo red and textile industry effluent. Pseudomonas sp. SU-EBT decolorized several individual textile dyes, dye mixtures and textile industry effluent, thus it is a useful strain for the development of effluent treatment methods in textile processing industries.     

Biodegradation of reactive textile dye Red BLI by an isolated bacterium Pseudomonas sp. SUK1

A novel bacterial strain capable of decolorizing reactive textile dye Red BLI is isolated from the soil sample collected from contaminated sites of textile industry from Solapur, India. The bacterial isolate was identified as Pseudomonas sp. SUK1 on the basis of 16S rDNA analysis. The Pseudomonas sp. SUK1 decolorized Red BLI (50 mg l(-1)) 99.28% within 1h under static anoxic condition at pH range from 6.5 to 7.0 and 30 degrees C. This strain has ability to decolorize various reactive textile dyes. UV-Vis spectroscopy, FTIR and TLC analysis of samples before and after dye decolorization in culture medium confirmed decolorization of Red BLI. A significant increase in the activities of aminopyrine N-demethylase and NADH-DCIP reductase in cells obtained after decolorization indicates involvement of these enzymes in the decolorization process. Phytotoxicity testing with the seeds of Sorghum vulgare and Phaseolus mungo, showed more sensitivity towards the dye, while the products obtained after dye decolorization does not have any inhibitory effects.     

Decolorization of triphenylmethane and azo dyes by Citrobacter sp.

A Citrobacter sp., isolated from soil at an effluent treatment plant of a textile and dyeing industry, decolorized several recalcitrant dyes except Bromophenol Blue. More than 90% of Crystal Violet and Methyl Red at 100 M were reduced within 1 h. Gentian Violet, Malachite Green and Brilliant Green lost over 80% of their colors in the same condition, but the percentage decolorization of Basic Fuchsin and Congo Red were less than the others, 66 and 26%, respectively. Decolorization of Congo Red was mainly due to adsorption to cells. Color removal was optimal at pH 7–9 and 35–40 °C. Decolorization of dyes was also observed with extracellular culture filtrate, indicating the color removal by enzymatic biodegradation.     

Biodegradation of diazo reactive dye Navy blue HE2R (Reactive blue 172) by an isolated <Emphasis Type="Italic">Exiguobacterium</Emphasis> sp. RD3

The diazo reactive dye Navy blue HE2R (50 mg/L) was decolorized up to 91.2% within 48 h at static condition by the Exiguobacterium sp. isolated from the dyestuff contaminated soil, collected from the textile industrial area Solapur, India. It showed ability to decolorize seven different reactive textile dyes. Maximum decolorization was observed at 30°C and pH 7. The presence and significant increase in the activity of enzymes lignin peroxidase, laccase, and azoreductase indicated prominent role of these enzymes in the decolorization of Navy blue HE2R. The degradation metabolites were analyzed by UV-Vis spectroscopy, TLC, HPLC, and FTIR spectroscopy. A possible pathway for biodegradation of this diazo reactive dye was proposed with the help of GC-MS analysis. The phytotoxicity studies confirmed the environmentally safe nature of degradation products.     

The role of enzymes produced by white-rot fungus Irpex lacteus in the decolorization of the textile industry effluent

The textile industry wastewater has been decolorized efficiently by the white rot fungus, Irpex lacteus, without adding any chemicals. The degree of the decolorization of the dye effluent by shaking or stationary cultures is 59 and 93%, respectively, on the 8th day. The higher level of manganese-dependent peroxidase (MnP) and non-specific peroxidase (NsP) was detected in stationary cultures than in the cultures shaken. Laccase activities were equivalent in both cultures and its level was not affected significantly by the culture duration. Neither lignin peroxidase (LiP) nor Remazol Brilliant Blue R oxidase (RBBR ox) was detected in both cultures. The absorbance of the dye effluent was significantly decreased by the stationary culture filtrate of 7 days in the absence of Mn (II) and veratryl alcohol. In the stationary culture filtrate, three or more additional peroxidase bands were detected by the zymogram analysis.     

Comparison of static and shake culture in the decolorization of textile dyes and dye effluents byPhanerochœte chrysosporium

Decolorization of several dyes (Red HE-8B, Malachite Green, Navy Blue HE-2R, Magenta, Crystal Violet) and an industrial effluent with growing cells ofPhanerochœte chrysosporium in shake and static culture was demonstrated. All the dyes and the industrial effluent were decolorized to some extent with varying percentages of decolorization (20–100%). The rate of decolorization was very rapid with Red HE-8B, an industrial dye. Decolorization rates for all the dyes in static condition were found to be less than the shake culture and also dependent on biomass concentration.     

Decolorization of reactive dyes by mixed cultures isolated from textile effluent under anaerobic conditions

In the present study mixed cultures that could grew in the molasses media were isolated from textile dye effluent and its decolorization activity was studied in a batch system under anaerobic conditions, in order to determine the optimal conditions required for the highest decolorization activity. The optimum pH value for decolorization was determined as 8 for all the dyes tested. In the experiment with pH 8 dye decolorizations by mixed cultures were investigated at about 96.2–1031.3 mg l⁻¹ initial dye concentrations. The highest dye removal rates of mixed cultures were 94.9% for Reactive Red RB, 91.0% for Reactive Black B and 63.6% for Remazol Blue at 953.2, 864.9 and 1031.3 mg l⁻¹ initial dye concentrations respectively within 24 h incubation period. When the Reactive Red RB was used, approximately 82–98% total color removal was obtained at between 96.2 and 953.2 mg l⁻¹ initial dye concentrations after 12 h of incubation at 35 °C. These results show that our enriched mixed cultures have the potential to serve as an excellent biomass for the use in reactive dye removal from wastewaters under anaerobic conditions.     

Phylogenetic diversity and biotechnological potentials of marine bacteria from continental slope of eastern Arabian Sea

Marine environments are substantially untapped source for the isolation of bacteria with the capacity to produce various extracellular hydrolytic enzymes, which have important ecological roles and promising biotechnological applications. Hydrolases constitute a class of enzymes widely distributed in nature from bacteria to higher eukaryotes. Marine microbial communities are highly diverse and have evolved during extended evolutionary processes of physiological adaptations under the influence of a variety of ecological conditions and selection pressures. A number of marine hydrolases have been described, including amylases, lipases and proteases, which are being used extensively for biotechnological applications. The present study was carried out to isolate marine bacteria from continental slope sediments of the eastern Arabian Sea and explore their biotechnological potential. Among the 119 isolates screened, producers of amylases (15%), caseinases (40%), cellulases (40%), gelatinases (60%), lipases (26%), ligninases (33%), phytase (11%) and Malachite Green dye degraders (16%) were detected. Phylogenetic analysis based on 16S rRNA gene sequencing showed that predominant marine sediment bacteria possessing more than four enzymatic activities belonged to the phyla Firmicutes and Proteobacteria, was assigned to the genera Bacillus, Planococcus, Staphylococcus, Chryseomicrobium, Exiguobacterium and Halomonas. Biodegradation of the dye Malachite Green using the liquid decolorization assay showed that both the individual cultures (Bacillus vietnamensis, Planococcus maritimus and Bacillus pumilus) and their consortium were able to decolorize more than 70% of dye within 24?h of incubation. This is the first report on diversity and extracellular hydrolytic enzymatic activities and bioremediation properties of bacteria from continental slope sediment of eastern Arabian Sea.     

Effect of environmental parameters on decolorization of textile wastewater using Phanerochaete chrysosporium

Effect of various parameters such as size of inoculum, temperature, carbon source on decolorization of textile wastewater by Phanerochaete chrysosporium was investigated. Textile wastewater decolorization occurred during the primary phase of growth and secondary metabolism in carbon and nitrogen limited medium, respectively. It was found that glucose concentration up to 0.3 g/l has considerable effect on decolorisation rate. Further, it was also found that the concentration of the organic nitrogen of the effluent stream was sufficient to furnish the decolorisation process. It was observed that the inoculum size in this case within 10% increased the decolorisation rate rapidly. It was found that the temperature rise from 20 to 38 °C enhanced the rate of decolorization. The optimum temperature for decolorisation was found to be about 35 °C. Effect of pH from 2-4 on decolorization was also investigated. It is concluded that using Phanerochaete chrysosporium, decolorization of the azo dye containing effluent of the textile industry was achieved to about 96% within 28 h of operation.     

Studies on phytoremediation potentiality of Typhonium flagelliforme for the degradation of Brilliant Blue R

In vitro culture plants of Typhonium flagelliforme were found to decolorize a variety of dyes, including Malachite Green, Red HE 8B, Methyl Orange, Reactive Red 2, Direct Red 5B (DR5B), Red HE 7B, Golden Yellow HER, Patent Blue, and Brilliant Blue R (BBR), to varying extents within 4 days. The enzymatic analysis of plant roots of aseptically raised plantlets performed before and after degradation of the dye BBR by these plantlets showed a significant induction in the activities of peroxidase, laccase, tyrosinase, and 2,6-dichlorophenol-indophenol reductase, which indicated the involvement of these enzymes in the metabolism of the dye. Comparative study of the enzyme status of the plants Typhonium flagelliforme and Blumea malcolmii during the degradation of DR5B and BBR showed marked variations in the enzyme profile with respect to the use of different sources of the enzyme. Phytoremediation of BBR using Typhonium flagelliforme was confirmed with high performance liquid chromatography and Fourier transform infrared spectroscopy analysis performed before and after the degradation of the dye. One of the products of the metabolism of the dye was identified as 4-(4-ethylimino-cyclohexa-2,5-dienylidinemethyl)-phenylamine with the aid of gas chromatography–mass spectroscopy (GC–MS) analysis. Significant decrease in the American Dye Manufacturer’s Institute, biological oxygen demand, and chemical oxygen demand values of synthetic mixture of textile dyes and industrial effluent confirmed the decolorization and detoxification. Phytotoxicity studies also revealed the nontoxic nature of the metabolites of BBR.     

Evidence on manganese peroxidase and tyrosinase expression during decolorization of textile industry dyes by Trichosporon akiyoshidainum

Textile dyes are engineered to be resistant to environmental conditions. During recent years the treatment of textile dye effluents has been the focus of significant research because of the potentially low cost of the process. Mechanisms of biological textile dye decolorization depend greatly on the chemical structure of the dye and the microorganisms used. While basidiomycetous filamentous fungi are well recognized for dye decolorization through ligninolytic enzymes, reports on textile dye decolorization mechanisms of basidiomycetous yeasts have been scarce. Decolorization of several textile dyes by Trichosporon akiyoshidainum occurs during the first 12 h of cultivation. This fast decolorization process could not be solely related to siderophore production or dye sorption to biomass; it was shown to be a co-metabolic process. T. akiyoshidainum could use glucose, sucrose, and maltose as alternative carbon sources, and urea as an alternative nitrogen source with similar decolorization rates. The activity of two enzymes, manganese peroxidase and tyrosinase, were induced by the presence of dyes in the culture media, pointing to their potential role during the decolorization process. Manganese peroxidase titers reached 666 U l⁻¹ to 10538 U l⁻¹, while tyrosinase titers ranged between 84 U l⁻¹ and 786 U l⁻¹, depending on the dye tested. The present work provides a useful background to propose new eco-friendly alternatives for wastewater treatment in textile dying industries.     

Significant reduction in toxicity,BOD, and COD of textile dyes and textile industry effluent by a novel bacterium <Emphasis Type="Italic">Pseudomonas</Emphasis> sp. LBC1

The 16S rRNA sequence analysis and biochemical characteristics were confirmed that the isolated bacterium is Pseudomonas sp. LBC1. The commonly used textile dye, Direct Brown MR has been used to study the fate of biodegradation. Pseudomonas sp. LBC1 showed 90% decolorization of Direct Brown MR (100 mg/L) and textile industry effluent with significant reduction in COD and BOD. The optimum condition for decolorization was 7.0 pH and 40°C. Significant increase in a activity of extracellular laccase suggested their possible involvement in decolorization of Direct Brown MR. Biodegradation metabolites viz. 3,6-dihydroxy benzoic acid, 2-hydroxy-7-aminonaphthol-3-sulfonic acid, and p-dihydroperoxybenzene were identified on the basis of mass spectra and using the 1.10 beta Shimadzu NIST GC–MS library. The Direct Brown MR and textile industry effluent were toxic to Sorghum bicolor and Vigna radiata plants as compared to metabolites obtained after decolorization. The Pseudomonas sp. LBC1 could be useful strain for decolorization and detoxification of textile dyes as well as textile industry effluent.     

Phytoremediation potential of Portulaca grandiflora Hook. (Moss-Rose) in degrading a sulfonated diazo reactive dye Navy Blue HE2R (Reactive Blue 172)

Wild and tissue cultured plants of Portulaca grandiflora Hook. have shown to be able to decolorize a sulfonated diazo dye Navy Blue HE2R (NBHE2R) up to 98% in 40 h. A significant induction in the activities of lignin peroxidase, tyrosinase and DCIP reductase was observed in the roots during dye decolorization. The wild plants and tissue cultures could independently decolorize and degrade NBHE2R into metabolites viz. N-benzylacetamide and 6-diazenyl-4-hydroxynaphthalene-2-sulfonic acid. A dye mixture and a textile effluent were also decolorized efficiently by P. grandiflora. The phytotoxicity study revealed reduction in the toxicity due to metabolites formed after dye degradation.     

Biological decolorization of dye solution containing Malachite Green by microalgae Cosmarium sp

The potential of Cosmarium species, belonging to green algae, was investigated as a viable biomaterial for biological treatment of triphenylmethane dye, Malachite Green (MG). The results obtained from the batch experiments revealed the ability of algal species in removing dye. The effects of operational parameters (temperature, pH, dye concentration and algal concentration) on decolorization were examined. Optimal initial pH was determined 9. The stability and efficiency of the algae in long-term repetitive operations were also examined. Michaelis-Menten kinetics was used to describe the apparent correlation between the decolorization rate and the dye concentration. The optimal kinetic parameters, nu(max) and K(m) are 7.63 mg dye g cell(-1)h(-1) and 164.57 ppm, respectively. All assays were conducted in triplicates.     

一株高效广谱染料降解细菌的分离鉴定及脱色特性研究

通过梯度驯化,从印染废水长期污染土壤中分离筛选出能以4种不同结构类型的染料(刚果红、美蓝、孔雀绿和活性艳蓝KN-R)为唯一碳源的菌株XSMR,根据其形态学特征和生理生化鉴定及16S rDNA序列分析,初步鉴定为无色杆菌属(Achromobacter sp.)的菌株。菌株XSMR对4种染料均具有强的脱色降解能力,且对染料脱色的同时,自身能够生长繁殖,培养24h菌体干重超过不加染料的对照。在振荡培养条件下对该菌株的脱色反应条件进行研究,结果表明,当刚果红、美蓝、孔雀绿及活性艳蓝KN-R的初始浓度分别小于200mg/L、200mg/L、150mg/L及150mg/L时,在pH7.5、温度35℃、接种量4%(V/V)条件下,接种菌株XSMR脱色14h对4种染料的脱色率均可达到98%以上。通过对降解产物的紫外-可见光谱分析,进一步证明了菌株XSMR能彻底降解染料。菌株XSMR对染料脱色的机理包括生物降解和菌株吸附两方面。     

Biodegradation of Reactive Blue 59 by isolated bacterial consortium PMB11

Morphologically different, three bacterial strains, capable of decolorizing Reactive Blue 59 were isolated from dye effluent contaminated soil sample, collected from Ichalkaranji, India. The individual bacterial strains viz. Bacillus odysseyi SUK3, Morganella morganii SUK5 and Proteus sp. SUK7 decolorized Reactive Blue 59 (50 mg l(-1)) completely within 60, 30, 24 h, respectively, while the bacterial consortium PMB11 of these strains required 3 h for the complete decolorization. The decolorization was confirmed by UV-Vis spectroscopy. Further, the biodegradation of Reactive Blue 59 in to different metabolites was confirmed by High performance liquid chromatography and Fourier transform infrared spectroscopy analysis. Significant increase in the activity of aminopyrine N-demethylase (AND) in the individual as well consortium cells, obtained after decolorization showed involvement of AND in the decolorization process. Phytotoxicity studies, revealed the nontoxic nature of the degraded metabolites of Reactive Blue 59 indicating effectiveness of bacterial consortium PMB11 for the treatment of textile effluent containing Reactive Blue 59.     

Bioremediation Perspective of Navy Blue Rx–Containing Textile Effluent by Bacterial Isolate

The aim of the present study was to investigate the textile effluent degrading potential of an isolated bacterium, Proteus sp. SUK7. The strain had the capacity to decolorize Navy Blue Rx–containing textile effluent up to 83% within 96 h. The maximum decolorization was observed under static conditions at pH 7.0 and 30°C. Reduction in the chemical oxygen demand (COD) and biological oxygen demand (BOD) of textile effluent was observed after treatment with Proteus sp. SUK7. Induction in the activities of laccase and aminopyrine N-demethylase was observed after decolorization, which indicates involvement of these enzymes in the decolorization process. The presence of various inducers was also found to have a modulatory effect on enzyme activities and the decolorization process. Biodegradation was confirmed using various analytical techniques, such as ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR), gas chromatography–mass spectrometry (GC-MS), and high-performance liquid chromatography (HPLC). A phytotoxicity study was performed to confirm the nontoxic nature of the degradation metabolites.     

海洋产电菌Shewanella marisflavi EP1的脱色特性

以一株新筛选得到的海洋产电菌Shewanella marisflavi EP1作为实验材料,研究了该菌株关于偶氮、蒽醌、三苯基甲烷等染料的脱色能力及脱色机制。结果表明,该菌株对这些染料均具有较好的脱色能力,最高脱色容量达到925 mg染料/(g细胞干重.d)。EP1能利用葡萄糖、蔗糖、木糖、乳酸、甲酸、柠檬酸等多种碳源将单偶氮染料丽春红2R脱色。脱色的pH、温度和NaCl浓度范围分别是:pH 6-10、15°C-40°C、0-8%。最优脱色条件:乳酸,pH 8、35°C、1%-2%NaCl,10 h内脱色率高达99.95%。分光光谱结果表明,在0-8%NaCl浓度范围内EP1脱色机制为降解脱色。