Swapnil S. Phugare

Evaluation of the efficacy of a bacterial consortium for the removal of color, reduction of heavy metals, and toxicity from textile dye effluent.

A microbial consortium DAS consisting three bacterial sp. originally obtained from dye contaminated sites of Solapur, India was selected because it was capable of decolorizing textile effluent and dye faster than the individual bacteria under static conditions. Identification of the isolates by 16S rRNA techniques revealed the isolates to be Pseudomonas species. The concerted metabolic activity of these isolates led to complete decolorization of textile effluent as well as Reactive Orange 16 (100 mg l(-1)) within 48-h at pH 7 and 30 degrees C. Studies involving Reactive Orange 16 (RO16) dye were carried with the bacterial consortium DAS to elucidate the mechanism of biodegradation. Induction of the laccase and reductase enzyme during RO16 decolorization indicated their role in biodegradation. The biodegradation of RO16 was monitored by using IR spectroscopy, HPLC and GC-MS analysis. Cytotoxicity, genotoxicity and phytotoxicity studies carried out before and after decolorization of the textile effluent revealed the nontoxic nature of the biotreated sample.

Textile dye degradation by bacterial consortium and subsequent toxicological analysis of dye and dye metabolites using cytotoxicity, genotoxicity and oxidative stress studies.

The present study aims to evaluate Red HE3B degrading potential of developed microbial consortium SDS using two bacterial cultures viz. Providencia sp. SDS (PS) and Pseudomonas aeuroginosa strain BCH (PA) originally isolated from dye contaminated soil. Consortium was found to be much faster for decolorization and degradation of Red HE3B compared to the individual bacterial strain. The intensive metabolic activity of these strains led to 100% decolorization of Red HE3B (50 mg l(-1)) with in 1h. Significant induction of various dye decolorizing enzymes viz. veratryl alcohol oxidase, laccase, azoreductase and DCIP reductase compared to control, point out towards their involvement in overall decolorization and degradation process. Analytical studies like HPLC, FTIR and GC-MS were used to scrutinize the biodegradation process. Toxicological studies before and after microbial treatment was studied with respect to cytotoxicity, genotoxicity, oxidative stress, antioxidant enzyme status, protein oxidation and lipid peroxidation analysis using root cells of Allium cepa. Toxicity analysis with A. cepa signifies that dye Red HE3B exerts oxidative stress and subsequently toxic effect on the root cells where as biodegradation metabolites of the dye are relatively less toxic in nature. Phytotoxicity studies also indicated that microbial treatment favors detoxification of Red HE3B.

Ecofriendly degradation, decolorization and detoxification of textile effluent by a developed bacterial consortium

Present study illustrates the effectual decolorization and degradation of the textile effluent using a developed bacterial consortium SDS, consisted of bacterial species Providencia sp. SDS and Pseudomonas aeuroginosa strain BCH, originally isolated from dye contaminated soil. The intensive metabolic activity of the consortium SDS led to complete decolorization of textile effluent within 20 h at pH 7 and temperature 30°C. Significant induction in the activities of veratryl alcohol oxidase, laccase, azoreductase and DCIP reductase were observed during decolorization, which indicates their involvement in decolorization and degradation process. The decolorization and biodegradation was monitored using UV-vis spectroscopy, IR spectroscopy, HPLC and HPTLC analysis. Toxicological analysis of effluent before and after treatment was performed using classical Allium cepa test. Investigations of various toxicological parameters viz, oxidative stress response, cytotoxicity, genotoxicity and phytotoxicity, collectively concludes that, the toxicity of effluent reduces significantly after treatment with consortium SDS.

Communal action of microbial cultures for Red HE3B degradation.

The consortium PMB11 consisting of three bacterial species, originally isolated from dye contaminated soil was identified as Bacillus odysseyi SUK3, Morganella morganii SUK5 and Proteus sp. SUK7. The consortium possessed the ability to decolorize various textile dyes as well as mixtures of dyes. PMB11 could decolorize Red HE3B (50 mg l(-1)) with 99% of decolorization within 12 h in nutrient broth, while in mineral medium it could decolorize up to 97% within 24h. Induction in the activities of various oxidative and reductive enzymes indicates the involvement of these enzymes in decolorization. Biodegradation of the dye was monitored using UV-vis spectroscopy, HPLC and FTIR analysis. The Red HE3B degradation pathway was proposed by GC-MS analysis. Various metabolites formed after the degradation were identified as 2,5-diaminobenzene 6-aminotriazine, aniline 2-sulfate, aniline 3-sulfate, 2-amino 5-chlorotriazine and naphthalene. Phytotoxicity studies revealed that metabolites formed after degradation were significantly less toxic in nature.

Purification and characterization of alkaline chitinase from Paenibacillus pasadenensis NCIM 5434.

An alkaline chitinase was purified from the bacterium Paenibacillus pasadenensis NCIM 5434 isolated from alkaline littoral soil of Lonar Lake. The chitinase was purified by ammonium sulfate precipitation followed by DEAE cellulose column chromatography. Enzyme was purified by 8.87 folds with 24.96% yield. Molecular characterization through SDS–PAGE analysis showed that it has molecular weight of about ∼35 kDa. The enzyme kinetics studies of purified chitinase revealed the following characteristics, Km 6.25 mg ml−1 and Vmax 434.78 µM for colloidal chitin as a substrate. The chitinase showed optimum pH 10 and temperature 37 °C. The enzyme exhibited significant activity up to 3% salt concentration, indicating saline nature. Its activity was enhanced with calcium, potassium and magnesium; whereas copper and mercury were found to be inhibitory. Since, it showed antifungal activity against Penicillium and Aspergillus, it could be used as powerful biocontrol agent.

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

ABSTRACT 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.

A study on significant microbial interaction leading to decolorization and degradation of textile dye Rubine 3GP.

The present study evaluates an obligatory interaction between the yeast Saccharomyces cerevisiae NCIM 3312 and the bacterium Pseudomonas sp. strain BCH3 for the biodegradation of the dye Rubin 3GP (R3GP). No significant degradation of R3GP was observed either by Saccharomyces cerevisiae NCIM 3312 or by Pseudomonas sp. strain BCH3, when both the cultures were tested individually under their respective optimum medium conditions. However, when both of them were allowed to intermingle with each other, R3GP was found to be degraded within 72 h, with a steady increase in β ‐1,3‐glucanase, chitinase and protease activity in the culture supernatant; indicating the possible role of Pseudomonas sp. strain BCH3 in cell wall lysis of S. cerevisiae NCIM 3312. The present study elucidates a rare microbial interaction where the bacterium Pseu‐domonas sp. strain BCH3 utilizes lysed yeast cells as the sole source of nutrients for its own growth and subsequently performs decolorization and degradation of R3GP. Enzymatic status showed involvement of various oxidoreductive enzymes like lignin peroxidase, laccase, DCIP reductase and azo reductase, indicating their role in decolorization and degradation of R3GP. Degradation was confirmed using HPLC, FTIR analysis and the biochemical pathway of degradation was elucidated by using GC‐MS analysis. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)