Synthetic dyes, extensively used in various industries, act as pollutants in the aquatic environment, and pose a significant threat to living beings. In the present study, we assessed the potential of a halophilic bacterium Salinivibrio kushneri HTSP isolated from a saltpan for decolorization and bioremediation of synthetic dyes. The genomic assessment of this strain revealed the presence of genes encoding the enzymes involved in decolorization mechanisms including FMN-dependent NADH azoreductase Clade III, which cleave the azo bond of the dye, and the enzymes involved in deamination and isomerization of intermediate compounds. The dye decolorization assay was performed using this bacterial strain on three water-soluble dyes in different concentrations: Coomassie brilliant blue (CBB) G-250 (500–3,000 mg/L), Safranin, and Congo red (50–800 mg/L). Within 48 h, more than 80% of decolorization was observed in all tested concentrations of CBB G-250 and Congo red dyes. The rate of decolorization was the highest for Congo red followed by CBB G-250 and then Safranin. Using UV-Visible spectrometer and Fourier Transform Infrared (FTIR) analysis, peaks were observed in the colored and decolorized solutions. The results indicated a breakdown of dyes upon decolorization, as some peaks were shifted and lost for different vibrations of aromatic rings, aliphatic groups (–CH2, –CH3) and functional groups (–NH, –SO3H, and –SO3−) in decolorized solutions. This study has shown the potential of S. kushneri HTSP to decolorize dyes in higher concentrations at a faster pace than previously reported bacterial strains. Thus, we propose that our isolated strain can be utilized as a potential dye decolorizer and biodegradative for wastewater treatment.

Marine ecosystems are least explored niches for yeast population and diversity. The present study aims to construct a comprehensive DNA barcode library for marine derived yeast species. As, we sequenced ITS gene for 1017 isolates belonging to 157 marine derived yeast species in 55 genera, 28 families, 14 orders, 8 classes of 2 Phyla (viz., Ascomycota and Basidiomycota) among which 13 yeast species were barcoded for the first time, we witnessed yeast species of both terrestrial and endemic marine origin. Difficulties were faced in taxonomic sequence validation due to large volume of sequencing trace files, variable length of sequences extracted and lack of reference sequences in public databases. Majority of the sequences (62.24%) were between 600 and 649 bps in length. K2P intra-species distance analysis conducted for selective groups yielded the average of 0.33% which was well within the previously proposed barcode gap value for yeast species (1.59%). ITS gene tree based identification conducted for selective species in Ascomycota and Basidomycota, precisely clustered the same species in single groups. About 60% of the yeast species recorded in the present study was previously unrecorded from the marine environment, among which 16.5% of yeast species were recognised human pathogens. Apart from releasing the barcode data in GenBank, provisions were made to access the entire dataset along with meta-data in the Barcode of life database under the project title “DNA barcoding marine yeast”. The present study constitutes the biggest dataset for the collection of marine yeast isolates and its DNA barcodes till date.