Heterotrophic nitrifying/aerobic denitrifying bacteria: Ammonium removal under different physical-chemical conditions and molecular characterization

Biological ammonium removal via heterotrophic nitrification/aerobic denitrification (HN/AD) was characterized for two isolates from a wastewater treatment station (WWTS). They were identified as Pseudomonas balearica UFV3 and Gordonia anticalis UFV4. Their ability to remove ammonium via NH/DA was validated by chromatography, and the influence of different physical-chemical factors on removal was evaluated. The presence of genes involved in conventional nitrification and denitrification processes was investigated via PCR and comparative genomics. Both isolates removed 100% of the ammonium in a medium containing citrate as its carbon source with a C/N ratio of 8, 3% salt, pH 7 and 30 degrees C. Nitrogen balance showed that approximately 55% of the ammonium removed was lost as N-2((g)), and 45% was assimilated. Molecular characterization revealed the absence of genes involved in autotrophic nitrification in the genome of the two isolates and the presence of genes involved in anaerobic denitrification only in P. balearica UFV3, suggesting the involvement of other genes in the HN/AD process. This was the first report of G. amicalis and P. balearica with the capability for HN/AD248CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIGsem informaçãosem informaçãosem informação8603-4600391375PETRÓLEO BRASILEIRO S. A. - PETROBRA

Effect of salinity in heterotrophic nitrification/aerobic denitrification performed by acclimated microbiota from oil-produced water biological treatment system

Mixed cultures salt acclimated showed high efficiency in heterotrophic nitrification/aerobic denitrification process in hypersaline conditions. They were able to remove 80% of ammonium in Heterotrophic Nitrification Medium (HNM) with 12 and 14% of salt. Above these salinity, the process still had 40% ammonium removal up to 20% of salt. Chromatography analysis validated the occurrence of the heterotrophic nitrification/aerobic denitrification process in all studied salinities (6%–20% of NaCl). However, with increasing salinity, the N2 production was smaller and took longer than the unsalted control. Microbial diversity analysis of mixed cultures showed that different groups of nitrifying microorganisms were involved in ammonium removal, including heterotrophic nitrifying/aerobic denitrifying genera such as Pseudomonas, Paracoccus, Bacillus, Halomonas, Acinetobacter and Klebsiella. In addition, this analysis also revealed that the acclimation process allowed the adaptation of the microorganisms to high saline conditions and ammonium removal up to 20% of salt. This work showed that heterotrophic nitrification/aerobic denitrification process could occur in high salinity after microbiota acclimation step, and these mixed acclimated cultures have a potential for application in hypersaline effluent treatment

Ammonium removal from high-salinity oilfield-produced water: assessing the microbial community dynamics at increasing salt concentrations

Water generated during oil exploration is chemically complex and contains high concentrations of ammonium and, in some cases, high salinity. The most common way to remove ammonium from effluent is a biological process, which can be performed by different routes and different groups of microorganisms. However, the presence of salts in the effluents could be an inhibiting factor for biological processes, interfering directly with treatment. This study aimed to evaluate changes in the profile of a microbial community involved in the process of ammonium removal when subjected to a gradual increase of salt (NaCl), in which the complete inhibition of the ammonium removal process occurred at 125 g L−1 NaCl. During the sludge acclimatization process, samples were collected and submitted to denaturing gradient gel electrophoresis (DGGE) and massive sequencing of the 16S ribosomal RNA (rRNA) genes. As the salt concentration increased in the reactor, a change in the microbial community was observed by the DGGE band profiles. As a result, there was a reduction in the presence of bacterial populations, and an increase in archaeal populations was found. The sequencing data suggested that ammonium removal in the reactor was carried out by different metabolic routes by autotrophic nitrifying bacteria, such as Nitrosococcus, Nitrosomonas, Nitrosovibrio, Nitrospira, and Nitrococcus; ammonium-oxidizing archaea Candidatus nitrosoarchaeum; ANAMMOX microorganisms, such as Candidatus brocadia, Candidatus kuenenia, and Candidatus scalindua; and microorganisms with the potential to be heterotrophic nitrifying, such as Paracoccus spp., Pseudomonas spp., Bacillus spp., Marinobacter sp., and Alcaligenes spp

Long-term avifaunal survey in an urban ecosystem from southeastern Brazil, with comments on range extensions, new and disappearing species

Urban avifaunal surveys in Brazil have been increasing in recent years, despite none of them consisting of long-term studies indicating events of regional colonization and/or missing species. Here, we present an avifaunal survey of an urbanized ecosystem in southeastern Brazil, carried out along 30 years, on the campus of the Pontifícia Universidade Católica de Minas Gerais, municipality of Belo Horizonte, Minas Gerais state. Inside the campus there is a forest reserve adjacent to a small lake. The inventory was mainly based on opportunistic records from the years 1982-2013. We recorded 134 bird species along the past 30 years. However, the present avifauna is composed of 123 species. A total of 97 species was recorded in the reserve, including the forest fragment and the adjacent lake, of which 44 were exclusive to this area. Nevertheless, the majority of the current species found in the study area is forest independent (N = 51) or semi-dependent (N = 46). There is a predominance of insectivorous (N = 43) and omnivorous (N = 29) species. The current avifauna is represented by 15 migratory species, which can be found both in the urbanized area and in the forest remnant. However, the majority of the species (N = 75) is resident in the area, including three invasive species, whereas few others (N = 28) are occasional visitors. The remaining species were probably introduced in the area. There were 11 cases of disappearing species, which include typical forest birds, and also species typical of wetlands and rural environments. We also comment on recent colonization and on the possible effects of isolation on birds. Probably, the majority of forest-dependents are on the brink of extinction in the forest fragment. Thus, the species' list provided here can be useful as a database for monitoring long-term effects of urbanization on this bird community