Extraction and Characterization of Extracellular Polymeric Substances in Biofilm and Sludge via Completely Autotrophic Nitrogen Removal Over Nitrite System

Abstract

Extracellular polymeric substances (EPS) were extracted from sludge and biofilm via the completely autotrophic nitrogen removal over nitrite (CANON) system. Tightly bound (TB)-EPS were extracted using four physical methods, namely, cationic exchange resin (CER), sonication, heating, and steaming. CER was the most effective and most suitable method for extraction among the four methods. Moreover, the ultraviolet-vis spectra of TB-EPS indicated that few cells were destroyed by the CER method. The major component contents of total EPS, proteins, carbohydrates, humic substances, and DNA in sludge were 60.77, 49.84, 21.63, and 9.01 mg/g volatile suspended solids (VSS) and 90.03, 29.01, 15.96, and 10.04 mg/g VSS in biofilm, respectively. The Fourier transform infrared (FT-IR) spectra results indicated differences in the EPS functional groups between biofilm and sludge. The results of the batch experiments showed that the biofilm activity was significantly higher than that of the sludge in the CANON system. Furthermore, biomass activity was probably influenced by the EPS composition and distribution in the sludge and biofilm.

Composition of EPS fractions from suspended sludge and biofilm and their roles in microbial cell aggregation

“…Compared with the SEPS and LB-EPS, the Raman spectra of TB-EPS had changed significantly. The infrared spectra also demonstrated the disparity between TB-EPS and other EPS fractions (Liang et al, 2010;Chen et al, 2013a). The TB-EPS from the S-sludge and biofilm have also similar qualitative Raman spectra, which Raman peaks were primary assigned the functional groups of proteins and polysaccharides (Fig.…”

Enzyme affinity to cell types in wheat straw (Triticum aestivum L.) before and after hydrothermal pretreatment

“…According to previous investigations, lignin coverage partly shields the cellulose from enzymatic attack by physically blocking access [19,41,42]. On the other hand, extraction of lignin also results in increased access to otherwise sealed cellulose within the cell wall matrix, thus increasing digestibility [43-45].…”

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

“…Indeed, the autotrophic nitrogen removal processes have shown great advantages over conventional nitrificationedenitrification processes with respect to high nitrogen removal rates (Tang et al, 2011;Tsushima et al, 2007) and no requirement for organic carbon sources (Van der Star et al, 2007). However, autotrophic nitrogen removal processes are limited by the very slow growth rates of both AerAOB (doubling time is approximately 8 h to several days (Chen et al, 2013a)) and AnAOB (doubling time is as long as 11e20 days (Strous et al, 1998)). …”

“…However, contradictory results were also obtained, e.g., a previous study by Liang et al (2010) reported that the EPS from AerAOB-enriched culture contained higher proteins than polysaccharides. In fact, the contradictory results of various investigations could be due to the different methods used for the extraction of EPS and the different protocols used for the qualification of polysaccharides and proteins (Chen et al, 2013b;Liang et al, 2010). Thus, a comparative study of EPS from different cultures should be conducted based on given extraction and measurement protocols.…”