Comparative Study of Enterobacter aerogenes and Mixed-Culture Bacteria for Acrylamide Biodegradation in Sequencing Batch Reactor Wastewater-Treatment Systems

Respirometric activities of unacclimatizedEnterobacter aerogenesand mixed culture bacteria in sequencing batch reactor systems in response to acrylamide and its biodegradation products

“…With regarding to nitrication, all four systems could completely nitrify ammonium resulting in the ammonium removal efficiencies of nearly 100%. Nitrite was not detectable 11,24 Mixed culture bacteria in the AS-2 and IFAS-2 systems contained nitriers that autotrophically removed the ammonium nitrogen.…”

“…6,[8][9][10] For wastewater treatment practices, additional carbon oxidation of acrylic acid and biological nitrogen removal (BNR) of ammonia would be required to meet the effluent standards. Jangkorn et al 11 studied the acrylamide biodegradation by E. aerogenes and mixed culture bacteria in the SBR activated sludge (AS) treatment system. They found that both E. aerogenes and mixed bacteria culture could completely mineralize acrylamide at 200 mg AM L À1 .…”

Untitled

“…Pure culture of E. aerogenes was inoculated into both AS-1 and IFAS-1 systems and the mixed culture of bacteria was seeded into both AS-2 and IFAS-2 systems. E. aerogenes was cultured by following the methodologies as described by Jangkorn et al [11]. Freeze-dried of E. aerogenes was resuscitated in the Wminimal medium to obtain E. aerogenes colonies for the incubation period of 48 h [17].…”

“…Furthermore, the MLVSS/MLSS ratios of E. aerogenes from the AS-1 and IFAS-1 systems as shown in Table 2 were relatively high, indicating that the accumulation of intracellular polyphosphate was not accumulated in this study. Jangkorn et al [11] reported that E. aerogenes accumulated intracellular polyphosphate granules when the growth rate of E. aerogenes was limited, which could be indicated by low MLVSS/MLSS ratios. For the attached biomass in the BioPortz media, it was found from the dataset I that the MLVSS/MLSS ratios were 0.92 and 0.82 in the IFAS-1 and IFAS-2 systems, respectively, indicating that both microbes did not accumulate significant amount of inorganic compounds in the cells.…”

“…It was discovered recently that E. aerogenes is a bacterium with a capable of degrading acrylamide, which is a carcinogen and hazardous compound [9], at the concentration as high as 5,000 mg AM/L in the culture media [10]. However, Jangkorn et al [11] reported that E. aerogenes in the pilot-scale SBR wastewater treatment system could not degrade acrylamide as much as it was reported due to the inhibition of free ammonia nitrogen (FAN). The FAN was accumulated in the SBR systems because heterotrophic nitrification of E. aerogenes was failed as a result of the accumulation of intracellular polyphosphate granules in the cells due to nutritional deficiency and unfavorable environmental conditions [12].…”