Presence of huge amount of salts in the wastewater of textile dyeing industry is one of the major limiting factors in the development of an effective biotreatment system for the removal of azo dyes from textile effluents. Bacterial spp. capable of thriving under high salt conditions could be employed for the treatment of saline dyecontaminated textile wastewaters. The present study was aimed at isolating the most efficient bacterial strains capable of decolorizing azo dyes under high saline conditions. Fiftyeight bacterial strains were isolated from seawater, seawater sediment, and saline soil, using mineral salt medium enriched with 100 mg l−1 Reactive Black-5 azo dye and 50 g NaCl l−1 salt concentration. Bacterial strains KS23 (Psychrobacter alimentarius) and KS26 (Staphylococcus equorum) isolated from seawater sediment were able to decolorize three reactive dyes including Reactive Black 5, Reactive Golden Ovifix, and Reactive Blue BRS very efficiently in liquid medium over a wide range of salt concentration (0-100 g NaCl l)⁻¹. Time required for complete decolorization of 100 mg dye l ⁻¹ varied with the type of dye and salt concentration. In general, there was an inverse linear relationship between the velocity of the decolorization reaction (V) and salt concentration. This study suggested that bacteria isolated from saline conditions such as seawater sediment could be used in designing a bioreactor for the treatment of textile effluent containing high concentration of salts.

We describe an efficient and environment-friendly approach to synthesizing porous calcium carbonate (CaCO 3 ) microspheres via carbon dioxide (CO 2 ) mineralization using naturally occurring microalgae as a bio-template. The CaCO 3 microspheres showed a surface area of 39.1 m 2 g À1 with pore diameters ranging between 12 and 30 nm. Exploiting its highly porous trait, this bio-mimetically manufactured particle was used as an inert support for silver nanoparticles (nAg). The characteristics of the composite Ag-embedded CaCO 3 microspheres were examined by FE-SEM, TEM, XRD, BET surface area analysis, XPS and TG-DTA, confirming that the nAg particles were compatible with and uniformly distributed on the CaCO 3 microspheres. This novel composite, when added in some commercial paints, showed a rather expected yet potent antimicrobial activity against model bacteria such as Escherichia coli, Psychrobacter alimenterius and Staphylococcus euroum. The minimum bactericidal concentration to kill 99% of bacteria was found to be 0.1 mg mL À1 . Moreover, this potency was not accompanied by any quality degradation of the paint color. In view of all this, it is believed that the proposed "green" way of making CaCO 3 microspheres has great potential for commercialization.

Wastewater from textile processing and dyestuff manufacturing industries contains different kinds of dyes and their metabolites, which are mutagenic and carcinogenic in nature. Such wastewater should be treated in order to avoid ground and surface water contamination. The aim of present research was to isolate such bacterial strains which are capable of degrading dye-originated aromatic amines. Ten samples of wastewater and sludge were collected from outlets and wastewater streams of different textile industries. The analysis of wastewater showed a wide variation in the pH (8.10-12.3), total dissolved solids (500-20100 mg L ) using 10 mL wastewater/sludge as inoculum source. Based on ability to degrade 4-nitroaniline most efficient bacterial strain was identified as Raoultella planticola (IL11) through 16S rRNA gene analysis. These findings suggest that the indigenous bacterial strains have potential for bioremediation of dye-containing textile effluents, and for complete mineralization, 4-nitroaniline degrading strains may be used in combination with dye degrading strains.