title: Azo dye load-shock on relative behavior of biofilm and suspended growth configured periodic discontinuous batch mode operations: critical evaluation with enzymatic and bio-electrocatalytic analysis.
abstract: Effect of dye (C.I.Acid Black 10B) load-shock was comparatively evaluated in biofilm (self-immobilized) and suspended growth systems operated in periodic discontinuous batch mode (PDBR, anoxic-aerobic-anoxic) was investigated. At higher dye load (1250 mg dye/l), biofilm system showed relatively higher dye (74.5%) and COD (46%) removal efficiencies than the corresponding suspended mode operation (dye/COD removal efficiency, 42%/65%). Increment in dye load showed increment in azo reductase and dehydrogenase enzyme activities. Voltammograms (cyclic) showed higher reduction currents (RC) with increment in dye load specifically in biofilm system. Derivative cyclic voltammograms analysis depicted the involvement of mediators (NAD (+), FAD(+), etc.) which presumably played a major role in electron transport chain and dye degradation. Disappearance of peak (1612 cm(-1)) specific to azo group in FTIR spectrum, at higher loading rate in both the systems indicates the non-inhibitory and robust nature of PDBR operation.
authors.affiliation: Bioengineering and Environmental Centre (BEEC), CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India.
authors.forename: A
authors.initials: A
authors.lastname: Naresh Kumar
authors.affiliation: Bioengineering and Environmental Centre (BEEC), CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India.
authors.forename: C
authors.initials: C
authors.lastname: Nagendranatha Reddy
authors.affiliation: Bioengineering and Environmental Centre (BEEC), CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India.
authors.forename: R
authors.initials: R
authors.lastname: Hari Prasad
authors.affiliation: Bioengineering and Environmental Centre (BEEC), CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India. Electronic address: vmohan_s@yahoo.com.
authors.forename: S
authors.initials: S
authors.lastname: Venkata Mohan
mesh_terms: D001391:Azo Compounds / Q000378:metabolism* / Q000494:pharmacology*; D001419:Bacteria / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D018407:Bacterial Physiological Phenomena; D018441:Biofilms / Q000187:drug effects*; D019149:Bioreactors; D004396:Coloring Agents / Q000378:metabolism; D055664:Electrochemical Techniques; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D009601:Nitroreductases; D010088:Oxidoreductases / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D014874:Water Pollutants, Chemical; D010088:Oxidoreductases; D009247:NADH, NADPH Oxidoreductases; D009601:Nitroreductases; C021106:azoreductase
keywords: Azo reductase; Dehydrogenase activity; Derivative cyclic voltammetry (DCV); Extracellular electron transfer (EET); Sequencing batch reactor (SBR); Sodium dodecyl sulphate-poly acrylamide gel electrophoresis (SDS-PAGE)