Crystal Violet Dye By Aeromonas Hharagava Lab Report

Decolorization of Crystal violet dye by Aeromonas hydrophila isolated from textile wastewater

Sujata Mani and Ram Naresh Bharagava*

Laboratory of Bioremediation and Metagenomics Research (LBMR)
Department of Environmental Microbiology (DEM), School for Environmental Sciences (SES)
Babasaheb Bhimrao Ambedkar University (A Central University)
Vidya Vihar, Raebareli Road, Lucknow - 226 025 (U.P.), India

*Corresponding Author: Dr. R. N. Bharagava
Tel.: [phone]; Fax: [phone]
E-mail: [e-mail], [e-mail]
Abstract
In this study, Crystal violet dye decolorizing bacterial strain SJ4 was isolated from textile wastewater and characterized as Aeromonas hydrophila by 16S rRNA gene
The medium used throughout the study was Minimal-salt-medium (MSM) amended with CV dye, which contained (in gl-1) K2HPO4, 5.22; KH2PO4, 4.08; MgSO4 .7H2O, 0.2; CaCl2, 0.55; NH4Cl, 0.4; agar, 1.5. A stock solution of the dye was prepared and used for all studies.
The sample collected was screened for CV dye decolorizing bacterial strains by inoculating 10 ml of wastewater into flask containing 100 ml of MSM broth. The flasks were incubated at 35°C under shaking conditions (120 rpm). After 48 hr of incubation period, 1ml of the culture broth was appropriately diluted and plated on MSM-CV dye amended agar plates. The morphologically distinct bacterial isolates showing clear zones around their colonies due to decolorization of dye were selected for further studies. These isolates were screened for their ability to decolorize CV in MSM-CV dye amended agar plates. The screening procedure in agar plate was continued till the complete decolorization was obtained at different concentrations of CV dye. The bacterial culture, which tolerated the higher concentration of the CV dye, was isolated through streak plate
The reaction mixture contained 100 µl of 0.1M guaiacol dissolved in 100mM Na-Acetate buffer at pH 5. Increase in absorbance was recorded for 30 min at 450nm, which was proportional to laccase activity (Parshetti et al., 2011). The activity of Lignin peroxidase was determined by monitoring the conversion of propanaldehyde at 300 nm for 30 min in a reaction mixture of 10µl enzyme extract and 100µl containing 100mM n-propanol, 250 mM tartaric acid and 10 mM H2O2 (Kalyani et al., 2008). The enzyme activities were measured at room temperature. One enzyme unit was defined as an activity producing 1µmol product per min (Laccase) or consuming 1 µmol substrate per min (LiP) under the assay conditions (Novotny et al.,