Spectroscopic characterization of extracellular polymeric substances from a mixed culture dominated by ammonia-oxidizing bacteria

摘要: Extracellular polymeric substances (EPS) of aerobic (AerAOB) and anaerobic ammonium-oxidizing bacteria (AnAOB) are expected to have a significant impact on the performance autotrophic nitrogen removal in engineered systems. However, there few investigations EPS AerAOB AnAOB, results contradictory. In this study, photometric measurements indicated that AerAOB- (31.74 ± 1.48 mg/g-VSS, volatile suspended solids) AnAOB-enriched cultures (30.12 1.52 mg/g-VSS) contained more polysaccharides than did conventional activated sludge from municipal wastewater treatment facility (10.76 0.83 mg/g-VSS). addition, culture was dominated by proteins, leading considerably higher protein/polysaccharide ratio (2.64 0.12) those AerAOB-enriched (0.56 0.03) (1.96 0.09). Characterization using Fourier transform infrared spectroscopy (FTIR) revealed dominance amide bands and/or polysaccharide-associated AnAOB AerAOB. These corroborate data measurements. (23.1% 1.2%) (21.9% 1.1%) had portion α-helices, which is key protein secondary structure determines flocculation or cell aggregation, I band (16.7% 0.8%). X-ray photoelectron (XPS) characterization also significantly different functionalities among three mixed cultures; e.g., O-(C,H), indicates presence polysaccharides, richer AerAOB, whereas protonated amines, commonly found amino acids sugars, accounted for large AnAOB. The study can potentially expand our knowledge microbial aggregates responsible removal.