Kisan M. Kodam

Decolorization and degradation of Disperse Blue 79 and Acid Orange 10, by Bacillus fusiformis KMK5 isolated from the textile dye contaminated soil

The release of azo dyes into the environment is a concern due to coloration of natural waters and due to the toxicity, mutagenicity and carcinogenicity of the dyes and their biotransformation products. The dye degrading bacterial strain KMK 5 was isolated from the textile dyes contaminated soil of Ichalkaranji, Maharashtra, India. It was identified as Bacillus fusiformis based on the biochemical and morphological characterization as well as 16S rDNA sequencing. KMK 5 could tolerate and degrade azo dyes, Disperse Blue 79 (DB79) and Acid Orange 10 (AO10) under anoxic conditions. Complete mineralization of DB79 and AO10 at the concentration of 1.5g/l was observed within 48h. This degradation potential increased the applicability of this microorganism for the dye removal.

Novel route for rapid biosynthesis of copper nanoparticles using aqueous extract of Calotropis procera L. latex and their cytotoxicity on tumor cells.

This paper accounts for novel, low-cost, eco-friendly route for rapid biosynthesis of copper nanoparticles. Cysteine proteases present in the latex of Calotropis procera L. were used to fabricate copper nanoparticles from copper acetate. Copper nanoparticles were initially characterized by transmission electron microscopy (TEM) and X-ray diffraction technique (XRD). Transmission electron microscopy (TEM) was used to estimate the size and shape of nanoparticles. The average size of copper nanoparticles was found to be 15 ± 1.7 nm. Energy dispersive analysis of X-rays (EDAX) showed distinct peaks of copper. Fourier transform infrared spectroscopy (FTIR) was performed to confirm capping behavior of the latex proteins that contributed to long term stability of copper nanoparticles (6 months) in aqueous medium. Copper nanoparticles synthesized by above method were monodisperse type. Cytotoxicity studies of latex stabilized copper nanoparticles were carried out on HeLa, A549 and BHK21 cell lines by MTT dye conversion assay. HeLa, A549 and BHK21 cells showed excellent viability even at 120 μM concentration of copper nanoparticles. This shows that copper nanoparticles synthesized by above method hold excellent biocompatibility.

Decolorization and biodegradation of azo dye, reactive blue 59 by aerobic granules.

The present study deals with development of aerobic granules from textile wastewater sludge and challenged with different concentration of reactive blue 59 (RB59) to test their dye degradation potential. The granules efficiently degraded reactive blue 59 and also sustained higher dye loading of up to 5.0 g l(-1). The significant induction of enzymes azoreductase and cytochrome P-450 indicated their prominent role in the dye degradation while genotoxicity studies demonstrated that the biotransformed product of the dye as non-toxic. The microbial community of the textile dyes degrading aerobic sludge granules analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), revealed significantly diverse dye degrading microbial community belonging to alpha-, beta-, and gamma-proteobacteria.

Simultaneous reduction of Cr(VI) and oxidation of As(III) by Bacillus firmus TE7 isolated from tannery effluent.

Hexavalent chromium [Cr(VI)] and arsenite [As(III)] are the most toxic forms of chromium and arsenic respectively, and reduction of Cr(VI) to Cr(III) and oxidation of As(III) to As(V) has great environmental implications as they affect toxicity and mobility of these toxic species. Bacillus firmus strain TE7, resistant to chromium and arsenic was isolated from tannery effluent. The strain exhibited ability to reduce Cr(VI) and oxidize As(III). It reduced 100 mg L(-1) Cr(VI) within 60 h in nutrient broth and oxidized 150 mg L(-1) As(III) within 10 h in minimal medium. It also completely reduced 15 mg L(-1) Cr(VI) and oxidized 50 mg L(-1) of As(III) simultaneously in minimal medium. To the best of our knowledge, this is the first bacterial strain showing simultaneous reduction of Cr(VI) and oxidation of As(III) and is a potential candidate for bioremediation of environments contaminated with these toxic metal species.

Simultaneous decolorization of reactive Orange M2R dye and reduction of chromate by Lysinibacillus sp. KMK-A.

Azo dyes constitute the largest and diverse group of dyes, widely used in number of industries that are contributing toward organic and inorganic load of effluent treatment. In the present study, Lysinibacillus sp. KMK-A was able to effectively decolorize Orange M2R dye up to 2000 mg l(-1) (Vmax of 19.6 mg l(-1) h(-1) and Km of 439 mg l(-1)) and reduce Cr(VI) up to 250 mg l(-1) (Vmax of 3.6 mg l(-1) h(-1) and Km 28.3 mg l(-1)). It also has an ability of simultaneous decolorization of Orange M2R dye (200-1000 mg l(-1)) with reduction of Cr(VI) (50-200 mg l(-1)). Significant reduction in total organic carbon content, chemical and biological oxygen demand along with spectroscopic and chromatographic analysis confirmed the biotransformation of Orange M2R. Involvement of enzymes namely azoreductase and chromate reductase was observed during biotransformation. The phyto and geno toxicity studies demonstrated that metabolites of dye degradation were non-toxic. Higher tolerance with simultaneous decolorization and detoxification of azo dyes in presence of Cr(VI) makes Lysinibacillus sp. KMK-A, a potential candidate for eco-friendly remediation of metal contaminated dye effluents.

Effect of fly ash on biochemical responses and DNA damage in earthworm, Dichogaster curgensis

Fly ash is receiving alarming attention due to its hazardous nature, widespread usage, and the manner of disposal; leading to environmental deterioration. We carried out bio-monitoring and risk assessment of fly ash in earthworms as a model system. Dichogaster curgensis were allowed to grow in presence or absence of fly ash (0-40%, w/w) for 1, 7, and 14 d. The biochemical markers viz. catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione S-transferase (GST), and malondialdehyde (MDA) level were measured. The comet and neutral red retention assays were performed on earthworm coelomocytes to assess genetic damages and lysosomal membrane stability. The results revealed increased activities of SOD, GPx, GST, and MDA level in a dose-response manner while GR activity was decreased with increasing concentrations of fly ash. No obvious trend was observed in the CAT activity and fly ash concentration. Lysosomal membrane destabilization was noted in the earthworms exposed to 5% and more fly ash concentration in a dose and time dependent manner. The comet assay demonstrated that the fly ash induced DNA damage and DNA-protein crosslinks in earthworm coelomocytes.

Encapsulation of therapeutic lavender oil in an electrolyte assisted polyacrylonitrile nanofibres for antibacterial applications

Electrospinning, a feasible nanotechnology, has been exploited to engineer polyacrylonitrile (PAN) nanofibrous mats enclosing a representative hydrophobic drug like essential oil of lavender. The incorporation of electrolytic solution (NaCl) to polymer solution enhanced the electrospinning capability. Concentration as small as 0.3% (w/w) of electrolyte resulted in significant nanofibre morphologies, reduced average fibre diameter (88.44 nm) and it exhibited a narrow degree of polydispersity. The dosage of drug loaded in PAN nanofibres were varied from 12.5 to 200 μg mL−1 and their cytotoxicity against mouse fibroblast NIH/3T3 were studied in vitro. The antibacterial proficiency was gauged by challenging the material against Staphylococcus aureus and Klebsiella pneumoniae bacteria. The PAN nanofibres exhibited effective bactericidal properties of 14–15 mm zone of inhibition in at least 8 h, and it remained unaltered over 30 days. The in vitro release of the drug resulted in a dual drug release profiles with an initial burst as well as the diffusion dominated release, ensuing an enduring antibacterial activity. The incorporation of lavender oil improved the thermal stability resulting in a 20% residual mass at 800 °C, higher than pristine PAN nanofibers. The modelling of the interactions between PAN and the major antimicrobial components of lavender was performed to understand the chemistry between the additive and polymer. Thus, PAN nanofibres can be used to be a promising antibacterial material in various fields like biomedical, textile and water treatment applications.

Synthesis and biological evaluation of novel 2,4,6-triazine derivatives as antimicrobial agents

A series of 2,4,6-trisubstituted [1,3,5]triazines were synthesized and evaluated for their antimicrobial activity against two representative Gram-positive, Gram-negative bacteria and two fungi. Biological data revealed that among all the compounds screened, compounds 3f, 3g, 3h, 3i, 3m, 3o and 3p found to have promising antimicrobial activity against all the selected pathogenic bacteria and fungi. Out of the synthesized compounds seven analogues have shown MIC in the range of 6.25-12.5 μg/mL. These compounds were generally nontoxic and may prove useful as antimicrobial agents.

Toxicity study of ionic liquid, 1-butyl-3-methylimidazolium bromide on guppy fish, Poecilia reticulata and its biodegradation by soil bacterium Rhodococcus hoagii VRT1.

This study deals with the toxic effect of ionic liquid, 1-butyl-3-methylimidazolium bromide (BMImBr) on guppy fish, Poecilia reticulata. The fishes were exposed to various concentrations of ionic liquid for 96h. The activity of antioxidant enzymes viz. catalase, glutathione S-transferase and superoxide dismutase were found to be increased with increase in concentration. The BMImBr resistant bacterium were isolated from garden soil by enrichment method and identified as Rhodococcus hoagii VRT1 by 16S rDNA sequencing. An isolated bacterium was effective in biodegradation of compound in 8 days which was analyzed by changes in BOD and COD and later on confirmed by HRMS analysis. Higher concentrations of compound induced DNA damage in liver cells while degraded product did not show adverse impact on the DNA integrity.

Biomarker responses in the earthworm, Dichogaster curgensis exposed to fly ash polluted soils.

Earthworms are globally accepted as a model organism in terrestrial ecotoxicology for assessment of environmental pollution. This study evaluated and compared effects of fly ash polluted soils collected from two geographically different thermal power plants on biomarker responses in the earthworm, Dichogaster curgensis. To evaluate relationship between distance sampling and biomarker responses in the earthworm D. curgensis, soil samples at 0.5, 1 and 3km from thermal plant were analyzed for physico-chemical properties and metal concentrations. Biochemical alterations, lysosomal membrane stability, genotoxic effects, and histological changes were examined on 1, 7, and 14 d of exposure to fly ash contaminated soils collected from different thermal power plants. The activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA) levels were significantly increased, while glutathione reductase (GR) activity was found to be decreased in treated animals. Catalase (CAT) and glutathione-S- transferase (GST) activities were found to be increased initially up to 7d exposure and further decreased on 14d exposure. D. curgensis exposed to fly ash contaminated soils showed significant lysosomal membrane destabilization and DNA damage. Extensive histopathological changes were observed in the tissues of the body wall and intestinal tract of the exposed D. curgensis along with accumulation of heavy metals. These results demonstrate that soil pollution around thermal power plants has adverse biological effects of on the indicator organism D. curgensis and no correlation was found between distance and extent of biological biochemical responses.