Isolation of high-salinity-tolerant bacterial strains, Enterobacter sp., Serratia sp., Yersinia sp., for nitrification and aerobic denitrification under cyanogenic conditions

Abstract

Cyanides (CN(-)) and soluble salts could potentially inhibit biological processes in wastewater treatment plants (WWTPs), such as nitrification and denitrification. Cyanide in wastewater can alter metabolic functions of microbial populations in WWTPs, thus significantly inhibiting nitrifier and denitrifier metabolic processes, rendering the water treatment processes ineffective. In this study, bacterial isolates that are tolerant to high salinity conditions, which are capable of nitrification and aerobic denitrification under cyanogenic conditions, were isolated from a poultry slaughterhouse effluent. Three of the bacterial isolates were found to be able to oxidise NH(4)-N in the presence of 65.91 mg/L of free cyanide (CN(-)) under saline conditions, i.e. 4.5% (w/v) NaCl. The isolates I, H and G, were identified as Enterobacter sp., Yersinia sp. and Serratia sp., respectively. Results showed that 81% (I), 71% (G) and 75% (H) of 400 mg/L NH(4)-N was biodegraded (nitrification) within 72 h, with the rates of biodegradation being suitably described by first order reactions, with rate constants being: 4.19 h(-1) (I), 4.21 h(-1) (H) and 3.79 h(-1) (G), respectively, with correlation coefficients ranging between 0.82 and 0.89. Chemical oxygen demand (COD) removal rates were 38% (I), 42% (H) and 48% (G), over a period of 168 h with COD reduction being highest at near neutral pH.

Poly(butylene succinate)/bamboo powder blends as solid-phase carbon source and biofilm carrier for denitrifying biofilters treating wastewater from recirculating aquaculture system

“…The higher influent nitrate concentration (approximately 100 mg L −1 , nearly 6 times that of the PHBV/BP reactor of Chu and Wang, 2016) and shorter HRT (8 hours, half of that of the PHBV/BP reactor of Chu and Wang, 2016) used in this study may be partly responsible for the slower start-up. The start-up time in reactor I was much shorter than that of reactor II, indicating that the growth rate of biofilm in reactor I was significantly faster than that of reactor II and that salinity did not favor the growth of biofilm 30 – 32 . Further, the nitrate concentration profiles along the two reactors were studied to investigate the distribution of nitrate removal, the growth of biofilm and the denitrification potential, and the results are shown in Fig.…”

Simultaneous bisphenol F degradation, heterotrophic nitrification and aerobic denitrification by a bacterial consortium

“…Some Enterobacter , Citrobacter and Pseudomonas strains were reported to be capable of aerobic denitrification . Especially, Enterobacter and Pseudomonas strains exhibited good HN‐AD abilities . Moreover, some Enterobacter and Pseudomonas species had BPA‐degrading abilities .…”

“…4,31 -33 Especially, Enterobacter and Pseudomonas strains exhibited good HN-AD abilities. 5,32,34 Moreover, some Enterobacter and Pseudomonas species had BPA-degrading abilities. 35 -37 As the enriched bacterial consortium could degrade 50 mg L −1 BPA and 300 mg L −1 BPF, it was assumed that Enterobacter and Pseudomonas played important roles in BPF degradation.…”

Heterotrophic nitrification-aerobic denitrification potential of cyanide and thiocyanate degrading microbial communities under cyanogenic conditions

“…Nitrification under CNladen conditions was investigated using activated sludge obtained from a coking wastewater treatment plant and in this study, nitrification was inhibited when the media was supplemented with 0.2 mg CN -.L -1 [9], with SCNhaving a minimal inhibitory effect on nitrification. While in a separate study, the Enterobacter, Yersinia, and Serratia species were able to carry out nitrification under cyanogenic conditions (66 mg CN -.L -1 ), with minimal inhibition [33]. The high CNtolerance was attributed to the differences in composition, strength and overall quality of the microbial consortia used [34].…”