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Bioresource Technology Apr 2022To overcome a large amount of nitrite accumulation and poor removal rate for hydroxylamine, a simultaneous nitrification and denitrification (SND) bacterium was isolated...
To overcome a large amount of nitrite accumulation and poor removal rate for hydroxylamine, a simultaneous nitrification and denitrification (SND) bacterium was isolated and identified as Pseudomonas taiwanensis EN-F2 by DNA sequencing. Strain EN-F2 could remove 100% of ammonium (52.90 mg/L), 100% of hydroxylamine (23.32 mg/L), 86.99% of nitrite (56.32 mg/L) and 89.21% of nitrate (56.18 mg/L) with a maximum removal rate of 8.72, 2.12, 4.55 and 5.80 mg/L/h, respectively. Ammonium and hydroxylamine could be preferentially removed during the SND process. The nitrite removal rate and cell growth were substantially enhanced by 2.10 mg/L/h and 0.45 after supplementation of hydroxylamine. The specific activities of ammonia monooxygenase (AMO), hydroxylamine oxidoreductase (HAO), nitrate reductase (NR), nitrite reductase (NIR) were successfully detected as 0.95, 0.31, 0.42 and 0.03 U/mg protein, respectively. All results demonstrated that strain EN-F2 could perform SND to remove multiple nitrogen sources from wastewater.
Topics: Aerobiosis; Ammonium Compounds; Denitrification; Heterotrophic Processes; Hydroxylamine; Hydroxylamines; Nitrification; Nitrites; Nitrogen; Pseudomonas
PubMed: 35231598
DOI: 10.1016/j.biortech.2022.126912 -
The Science of the Total Environment Dec 2021Traditional nitrogen removal relies on the autotrophic nitrification and anaerobic denitrification process. In the system, autotrophic microorganisms achieve... (Review)
Review
Traditional nitrogen removal relies on the autotrophic nitrification and anaerobic denitrification process. In the system, autotrophic microorganisms achieve nitrification under aerobic condition and heterotrophic microorganisms complete the denitrification in anaerobic condition. As the two types of microorganisms have different tolerance on oxygen concentration, nitrification and denitrification are normally set in two compartments for high nitrogen removal. Therefore, large land occupying is required. In fact, there is a special type of microorganism called heterotrophic nitrification & aerobic denitrification microorganisms (HNADMs) which can oxidize ammonium nitrogen, and perform denitrification in the presence of oxygen. HNADMs have been reported in many environments. It was found that HNADMs could simultaneously achieve nitrification and denitrification. In addition, some HNADMs not only have the ability to remove nitrogen, but also have the ability to remove phosphorus. It suggests that HNADMs have great potential for pollution removal from wastewater. So far, individual work on single strain was carried out. Comprehensive summary of the HNADMs would provide a better picture for understanding and directing its application. In this paper, the studies related on HNADMs were reviewed. The nitrogen metabolism pathway of HNADMs was summarized. The impact of pH, DO, carbon source, and C/N on HNADMs growth and metabolism were discussed. In addition, the extracellular polymeric substance (EPS) production, quorum sensing (QS) secretion and P removal by HNADMs were displayed.
Topics: Aerobiosis; Denitrification; Extracellular Polymeric Substance Matrix; Heterotrophic Processes; Nitrification; Nitrites; Nitrogen; Wastewater
PubMed: 34428659
DOI: 10.1016/j.scitotenv.2021.149319 -
Letters in Applied Microbiology Feb 2022Bacterial species capable of performing both nitrification and denitrification in a single vessel under similar conditions have gained significance in the wastewater... (Review)
Review
Role of heterotrophic nitrifiers and aerobic denitrifiers in simultaneous nitrification and denitrification process: a nonconventional nitrogen removal pathway in wastewater treatment.
Bacterial species capable of performing both nitrification and denitrification in a single vessel under similar conditions have gained significance in the wastewater treatment scenario considering their unique character of performing the above reactions under heterotrophic and aerobic conditions respectively. Such a novel strategy often referred to as simultaneous nitrification and denitrification (SND) has a tremendous potential in dealing with various wastewaters having low C : N content, considering that the process needs very little or no external carbon source and oxygen supply thus adding to its cost-effective and environmentally friendly nature. Though like other micro-organisms, heterotrophic nitrifiers and aerobic denitrifiers convert inorganic or organic nitrogen-containing substances into harmless dinitrogen gas in the wastewater, their ecophysiological role in the global nitrogen cycle is still not fully understood. Attempts to highlight the role played by the heterotrophic nitrifiers and aerobic denitrifiers in dealing with nitrogen pollution under various environmental operating conditions will help in developing a mechanistic understanding of the SND process to address the issues faced by the traditional methods of aerobic autotrophic nitrification-anaerobic heterotrophic denitrification.
Topics: Aerobiosis; Denitrification; Nitrification; Nitrogen; Wastewater; Water Purification
PubMed: 34402087
DOI: 10.1111/lam.13553 -
Archives of Microbiology Aug 2020Environmental factors and available nutrients influence microbial communities, and with that, there exists a dynamic shift in community structure and hierarchy in... (Review)
Review
Environmental factors and available nutrients influence microbial communities, and with that, there exists a dynamic shift in community structure and hierarchy in wastewater treatment systems. Of the various factors, the availability and gradient of oxygen selectively enrich a typical microbial community and also form the community stratification which could be established through metagenomics studies. In recent years, metagenomics with various sets of bioinformatics tools has assisted in exploration and better insight into the organization and relation of the taxonomical and functional composition and associate physiological intelligence of the microbial communities. The microbial communities, under defined conditions acquire a typical hierarchy with flexible but active network of the metabolic route, which ensures the survival needs of every member residing in that community and their abundance. This knowledge of community functional organization defines the rule in designing and improving biodegradation processes in case of both aerobic and anaerobic systems.
Topics: Aerobiosis; Anaerobiosis; Biodegradation, Environmental; Bioreactors; Metagenomics; Microbiota; Sewage; Wastewater
PubMed: 32130435
DOI: 10.1007/s00203-020-01839-6 -
Journal of Applied Microbiology Jan 2022This study evaluated pH reduction and microbial growth during fermentation of maize stover (MS) mixed with banana pseudostem (BPS) under South Ethiopian conditions.
AIMS
This study evaluated pH reduction and microbial growth during fermentation of maize stover (MS) mixed with banana pseudostem (BPS) under South Ethiopian conditions.
MATERIALS AND RESULTS
The MS and BPS were chopped and mixed into six treatments (T): 80% BPS plus 20% DMS (T1), 70% BPS plus 30% DMS (T2), 40% BPS plus 60% FMS (fresh MS) (T3), 20% BPS plus 80% FMS (T4), 100% FMS (T5), and 95% BPS plus 5% molasses (T6). At 0, 7, 14, 30, 60, and 90 days, pH and dry matter were determined. Microbiological quality was assessed using plate counts and Illumina MiSeq sequencing. On day 60 and 90, aerobic stability was investigated. The results showed a significant reduction in pH in all mixtures, except in T1 and T2. Lactic acid bacteria counts reached a maximum in all treatments within 14 days. Sequencing showed marked changes in dominant bacteria, such as Buttiauxella and Acinetobacter to Lactobacillus and Bifidobacterium.
CONCLUSIONS
The fresh MS and BPS mixtures and fresh maize showed significant pH reduction and dominance of desirable microbial groups.
SIGNIFICANCE AND IMPACT OF THE STUDY
The study enables year-round livestock feed supplementation to boost milk and meat production in South Ethiopia.
Topics: Aerobiosis; Ethiopia; Fermentation; Musa; Silage; Zea mays
PubMed: 34133817
DOI: 10.1111/jam.15183 -
Environmental Research Nov 2022A thermotolerant strain isolated from sewage sludge (SS) composting was identified as Brevibacillus Agri N2, which showed the efficient capability for heterotrophic...
A thermotolerant strain isolated from sewage sludge (SS) composting was identified as Brevibacillus Agri N2, which showed the efficient capability for heterotrophic nitrification under high-temperature conditions. Incubation at 60 °C, strain N2 could utilize 45.47% of ammonium nitrogen (99.64 mg/L), 68.89% of hydroxylamine nitrogen (51.14 mg/L) and 76.77% of nitrite nitrogen (55.20 mg/L), with a minor part of nitrogen loss for 1.64%, 2.82% and 5.01%, respectively. The successful detection of ammonia monooxygenase, hydroxylamine oxidase, and nitrate oxidoreductase and PCR amplification of amoA, hao and nxrA genes provided evidence of nitrification ability by strain N2. Furthermore, single-factor experiments indicated that the optimal conditions for efficient nitrification performance by strain N2 were succinate as carbon source, 50 °C, C/N 12, pH 8 and 200 r/min. Strain N2 could perform the complete nitrification process, with minimal nitrogen loss at high temperature conditions, which indicated it had the potential for practical application for reducing nitrogen loss of SS composting.
Topics: Aerobiosis; Brevibacillus; Composting; Denitrification; Nitrification; Nitrogen; Sewage
PubMed: 35863446
DOI: 10.1016/j.envres.2022.113903 -
Bioresource Technology Nov 2021Yeast strain K1, isolated from surface sediment, was identified as Barnettozyma californica. The strain showed efficient heterotrophic nitrification and aerobic...
Yeast strain K1, isolated from surface sediment, was identified as Barnettozyma californica. The strain showed efficient heterotrophic nitrification and aerobic denitrification (HN-AD) at initial ammonium, nitrite and nitrate concentrations of 14-140 mg/L. Additionally, the optimum carbon source for its growth and nitrogen removal activity was sucrose, followed by glucose, acetate and citrate. The maximum removal efficiencies of ammonium, nitrite and nitrate were 99.11%, 99.13% and 98.84% under 48 h of culture with sucrose at 140 mg/L nitrogen and the corresponding removal efficiencies of total nitrogen were 90.16%, 86.65% and 81.48%, respectively. The optimum conditions for the inorganic nitrogen removal and growth of strain K1 were a C/N of 18 and a salinity of 5-15 ppt. The amoA, nirK and nosZ genes of K1 were detected. All the results suggest that B. californica K1 is capable of HN-AD and has the potential to remove inorganic nitrogen from wastewater.
Topics: Aerobiosis; Ammonium Compounds; Denitrification; Heterotrophic Processes; Nitrification; Nitrites; Nitrogen; Saccharomyces cerevisiae; Saccharomycetales
PubMed: 34332179
DOI: 10.1016/j.biortech.2021.125665 -
Journal of Basic Microbiology Feb 2022A strain was isolated from an activated sludge system and identified as Halomonas piezotolerans HN2 in this study, which is the first strain in H. piezotolerans with the...
A strain was isolated from an activated sludge system and identified as Halomonas piezotolerans HN2 in this study, which is the first strain in H. piezotolerans with the capability of heterotrophic nitrification and aerobic denitrification. Strain HN2 showed the maximum nitrogen removal rate of 9.10 mg/L/h by utilizing ammonium at the salinity of 3.0%. Under saline environment, HN2 could remove nitrogen efficiently in neutral and slightly alkaline environments, with the carbon sources of sodium succinate and sodium citrate and the C/N ratio of 15-20, and the maximum removal efficiencies of ammonium, nitrite, and nitrate were 100%, 96.35%, and 99.7%, respectively. The genomic information revealed the presence of amoA, napA, and nosZ genes in strain HN2, and the target bands of nirS were obtained via a polymerase chain reaction. Therefore, we inferred that ammonium was mainly utilized for the growth of strain HN2 through assimilation, and another part of the initial ammonium was converted into nitrate through nitrification, and then into gaseous nitrogen through denitrification. This report indicated the potential application of strain HN2 and other nitrifying and denitrifying Halomonas strains in the removal of nitrogen pollution in marine-related environments and also implies the important role of Halomonas in the nitrogen cycle process of the ocean.
Topics: Aerobiosis; Ammonium Compounds; Denitrification; Halomonas; Heterotrophic Processes; Nitrification; Nitrites; Nitrogen
PubMed: 34796543
DOI: 10.1002/jobm.202100446 -
Water Research Feb 2020The increasing use of perfluorooctanoic acid (PFOA) raises concerns about its potential toxicity to the environment. However, the interaction between PFOA and aerobic...
The increasing use of perfluorooctanoic acid (PFOA) raises concerns about its potential toxicity to the environment. However, the interaction between PFOA and aerobic granular sludge has never been documented. This work therefore aims to provide such support through investigating the fate of PFOA at environmentally relevant levels in aerobic granular sludge systems and its impact on aerobic granular sludge. Experimental results showed that 32.0%∼36.4% of wastewater PFOA was removed by aerobic granular sludge in stable operation when PFOA concentration was ranged from 0.1 to 1.0 mg/L. Mass balance analyses and X-ray photoelectron spectroscopy survey scan revealed that the removal of PFOA was dominated by adsorption rather than biodegradation, and sorption kinetic analysis indicated that inhomogeneous multilayer adsorption was responsible for this removal. The adsorbed PFOA deteriorated the settleability of granular sludge and biological nitrogen and phosphorus removal significantly. Experimental results showed that 1.0 mg/L PFOA inhibited anaerobic phosphate release, aerobic phosphate uptake, nitrate reduction, and nitrite reduction processes by 60%, 50%, 13.1%, and 5.8%, respectively. It was observed that PFOA induced large amounts of filamentous villus growing on the surface and increased the extracellular polymeric substances of granular sludge. Fourier-transform infrared spectra and X-ray photoelectron spectroscopy spectrum showed that several function groups in extracellular polymeric substances such as hydroxyl groups, amides and polysaccharides were affected by PFOA. It was also found that PFOA inhibited the cyclic transformations of polyhydroxyalkanoates and glycogen. Microbial community analyses showed that PFOA decreased the abundances of Nitrosomonas, Nitrospira, Accumulibacter, and other function microbes such as Rhodospirillaceae, Thauera, and Azoarcus.
Topics: Aerobiosis; Bioreactors; Caprylates; Fluorocarbons; Kinetics; Nitrogen; Sewage; Waste Disposal, Fluid
PubMed: 31706128
DOI: 10.1016/j.watres.2019.115249 -
Bioresource Technology Oct 2022Breeding high-efficiency heterotrophic nitrifying-aerobic denitrifying (SND) bacteria is important for the removal of biological nitrogen in wastewater treatment. In...
Breeding high-efficiency heterotrophic nitrifying-aerobic denitrifying (SND) bacteria is important for the removal of biological nitrogen in wastewater treatment. In this study, a high-efficiency SND mutant strain, ΔRhodococcus sp. CPZ 24, was obtained by ultraviolet-diethyl sulfate compound mutagenesis. The maximum nitrification and denitrification rates were 3.77 and 1.37 mg·L·h, respectively 30.30 % and 17.10 % higher than those of wild bacteria. Biolog technology and network model analysis revealed that ΔCPZ 24 significantly improved the utilisation ability and metabolic activity of organic carbon sources. Furthermore, the expression levels of the nitrogen removal function genes nxrA, nosZ, amoA, and norB in strain ΔCPZ 24 increased significantly. In actual sewage, mutant bacteria ΔCPZ 24 have a 95.05 % ammonia-nitrogen degradation rate and a 96.67 % nitrate-nitrogen degradation rate. These results suggested that UV-DES compound mutation was a successful strategy to improve the nitrogen removal performance of SND bacteria in wastewater treatment.
Topics: Aerobiosis; Denitrification; Heterotrophic Processes; Mutagenesis; Nitrification; Nitrites; Nitrogen; Rhodococcus; Wastewater
PubMed: 35905881
DOI: 10.1016/j.biortech.2022.127692