Anaerobic degradation of azo dye Drimaren blue HFRL in UASB reactor in the presence of yeast extract a source of carbon and redox mediator

• Published in: Biodegradation (Dordrecht) Vol. 23; no. 2; pp. 199 - 208
• Main Authors: Baêta, B. E. L., Aquino, S. F., Silva, S. Q., Rabelo, C. A.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.04.2012; Springer; Springer Nature B.V
• Subjects: Acclimatization; Ambient temperature; Anaerobiosis - drug effects; Analysis; Anthraquinones - metabolism; Aquatic Pollution; Azo compounds; Azo Compounds - metabolism; Azo dyes; Bacteria - drug effects; Bacteria - genetics; Base Sequence; Biodegradation; Biodegradation of pollutants; Biodegradation, Environmental - drug effects; Biological and medical sciences; Biological Oxygen Demand Analysis; Biomedical and Life Sciences; Bioreactors; Bioreactors - microbiology; Biotechnology; Carbon; Carbon - pharmacology; Chemical oxygen demand; Color; Color removal; Coloring Agents - metabolism; Denaturing Gradient Gel Electrophoresis; DNA, Ribosomal - genetics; Dyes; Environment and pollution; Extraction processes; Fatty acids; Fatty Acids, Volatile - analysis; Fundamental and applied biological sciences. Psychology; Geochemistry; Hydrogen-Ion Concentration - drug effects; Industrial applications and implications. Economical aspects; Life Sciences; Microbiology; Original Paper; Oxidation-Reduction - drug effects; Reactors; Rheology - drug effects; Sewage - microbiology; Sludge; Soil Science & Conservation; Solubility - drug effects; Temperature; Terrestrial Pollution; Vinyl Compounds - metabolism; Waste Disposal, Fluid; Waste Management/Waste Technology; Waste Water Technology; Water Management; Water Pollution Control; Yeast; Yeasts; Yeasts - metabolism; UASB reactor; Azo dye degradation; Anaerobic digestion; Industrial wastewater treatment; Color removal; Color; Upflow anaerobic sludge blanket reactor; Chemical mediator; Degradation; Bioreactor; Yeast extract; Anaerobe; Industrial waste water; Azo dye; Waste water purification
• ISSN: 0923-9820; 1572-9729
• DOI: 10.1007/s10532-011-9499-4

This paper presents results on anaerobic degradation of the azo dye blue HFRL in a bench scale Upflow anaerobic sludge blanket (UASB) reactor operated at ambient temperature. The results show that the addition of yeast extract (500 mg/L) increased color removal ( P  < 0.05) from 62 to 93% despite the low chemical oxygen demand (COD) removal (~35%) which happened due to volatile fatty acids (VFA) accumulation. There were no differences in color removal (~91%) when yeast extract (500 mg/L) was used in the presence or absence of glucose, suggesting that yeast extract acted as source of redox mediator (riboflavin) and carbon. The specific rate of dye removal increased along the operational phases and depended on the presence of yeast extract, suggesting progressive biomass acclimatization. Analysis of bacterial diversity by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR–DGGE) method showed there was biomass selection along the bioreactor operation and no evidence of azo dye degrading bacteria predominance. This strengthens the hypothesis that color removal happens extracellularly by the reduction of azo bond by reduced redox mediators, such as riboflavin, which is present in high amount in the yeast extract.