Characteristics of bacteria showing high denitrification activity in saline wastewater

Abstract

Aims: Denitrification efficiency at 10% salinity was compared with that at 2% salinity. The characteristics of bacterial strains isolated from the denitrification system, where an improvement of denitrification efficiency was observed at a high salinity were investigated. Methods and Results: Two continuous feeding denitrification systems for saline solutions of 2% and 10% salinity, were operated. Denitrification efficiency at 10% salinity was higher than that at 2% salinity. The bacterial strains were isolated using the trypticase soy agar (TSA) medium at 30°C. The phylogenetic analysis of 16S rRNA gene sequences of isolates indicated that halophilic species were predominant at 10% salinity. Conclusions: The improvement of denitrification efficiency at a high salinity was demonstrated. The strains isolated from the denitrifying system with 10% salinity were halophilic bacteria, Halomonas sp. and Marinobacter sp., suggesting that these bacteria show a high denitrifying activity at 10% salinity. Significance and Impact of the Study: The long‐term acclimated sludge used in this study resulted in high denitrification performance at a high salinity, indicating that the design of a high‐performance denitrification system for saline wastewater will be possible.

Nitrogen Transportation and Transformation Under Different Soil Water and Salinity Conditions

“…Thus, a long incubation time is necessary in future studies to confirm this aspect. In addition, µ w3 was enhanced by salinity in our experiment, and this result was similar to that of the studies by Hall et al [43] and Yoshie et al [44].…”

Biological treatment of ion-exchange brine regenerant for re-use: A review

“…The nature of this interaction is dependent on community development, which in turn is sensitive to salinity and acclimation conditions. However, it is apparent from some studies [15,38] that it is beneficial to the reduction rate to develop mixed communities (halophiles, such as Citrobacter sp. with non-halophiles [15]) rather than monocultures when treating brine containing either perchlorate or nitrate.…”

“…with non-halophiles [15]) rather than monocultures when treating brine containing either perchlorate or nitrate. In one study of a mixed denitrifying community, whilst the microbial diversity decreased on increasing the salinity from 20 to 100 gNaCl L −1 , denitrification increased at the higher concentration [38].…”

Direct Profiling of rRNA in Saline Wastewater Treatment Samples Using an Oligonucleotide Microarray

“…We used a DNA microarray to analyze activated sludge samples of saline industrial wastewater, which had been studied previously [22][23][24][25] . Samples were taken at 21 and 130 days from the start of the reactor's operation 22) .…”

“…Then, hybridization and washing conditions were optimized using cultured reference microorganisms. Furthermore, samples of saline industrial wastewater, which were previously characterized using molecular-based approaches [22][23][24][25] , were examined with the small-scale oligonucleotide microarray.…”