title: Selection of indicator bacteria based on screening of 16S rDNA metagenomic library from a two-stage anoxic-oxic bioreactor system degrading azo dyes.
abstract: Dye degradation has gained attention of late due to indiscriminate disposal from user industries. Enhancing efficiency of biological treatment provides a cheaper alternative vis-à-vis other advanced technologies. Dye molecules are metabolized biologically via anoxic and oxic treatments. In this study, bacterial community surviving on dye effluent working in anoxic-oxic bioreactor was analyzed using 16S rDNA approach. Azo-dye decolorizing and degrading bacterial community was enriched in lab-scale two-stage anoxic-oxic bioreactor. 16S rDNA metagenomic libraries of enriched population were constructed, screened and phylogenetically analyzed separately. Removal of approximately 35% COD with complete decolorization was observed in anoxic bioreactor. Process was carried out by uncultured gamma proteobacterium constituting 48% of the total population and 12% clones having homology to Klebsiella. Aromatic amines generated during partial treatment under anoxic bioreactor were treated by aerobic population having 72% unculturable unidentified bacterium and rest of the population consisting of Thauera sp., Pseudoxanthomonas sp., Desulfomicrobium sp., Ottowia sp., Acidovorax sp., and Bacteriodetes bacterium sp.
authors.affiliation: Environmental Impact & Risk Assessment Division and Environmental Genomic Unit, National Environmental Engineering Research Institute, Nehru Marg, Nagpur 440 020, India.
authors.forename: Nishant
authors.initials: N
authors.lastname: Dafale
authors.forename: Leena
authors.initials: L
authors.lastname: Agrawal
authors.forename: Atya
authors.initials: A
authors.lastname: Kapley
authors.forename: Sudhir
authors.initials: S
authors.lastname: Meshram
authors.forename: Hemant
authors.initials: H
authors.lastname: Purohit
authors.forename: Satish
authors.initials: S
authors.lastname: Wate
mesh_terms: D001391:Azo Compounds / Q000378:metabolism*; D001419:Bacteria / Q000145:classification / Q000378:metabolism*; D018533:Biomass; D019149:Bioreactors; D004396:Coloring Agents / Q000378:metabolism*; D004275:DNA, Ribosomal / Q000235:genetics / Q000378:metabolism*; D016680:Genome, Bacterial; D010100:Oxygen / Q000378:metabolism*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000378:metabolism*
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D010100:Oxygen