-
Bioresource Technology Nov 2023The heterotrophic nitrification-aerobic denitrification (HNAD) process can remove nitrogen and organic carbon under aerobic conditions. To get the in-depth mechanism of...
Exploring influence mechanism of small-molecule carbon source on heterotrophic nitrification-aerobic denitrification process from carbon metabolism, nitrogen metabolism and electron transport process.
The heterotrophic nitrification-aerobic denitrification (HNAD) process can remove nitrogen and organic carbon under aerobic conditions. To get the in-depth mechanism of the HAND process, a strain named Acinetobacter johnsonii ZHL01 was isolated, and enzyme activity, electron transport, energy production, and gene expression of the strain were studied with small-molecule carbon sources, including sodium citrate, sodium acetate, sodium fumarate, and sodium succinate. The HNAD pathway of ZHL01 was NH→NHOH → NO, and nitrogen balance analysis shows that ZHL01 could assimilate and denitrify 58.29 ± 1.05 % and 16.58 ± 1.07 % of nitrogen, respectively. The assimilation, the nitrification/denitrification, and the respiration processes were regulated by the concentration of reduced nicotinamide adenine dinucleotide (NADH) produced from the different metabolic pathways of small-molecule carbon sources. The HNAD process occurs to reduce intracellular redox levels related to NADH concentrations. This discovery provides a theoretical basis for the practical application of HAND bacteria.
Topics: Nitrification; Denitrification; Electron Transport; Carbon; NAD; Aerobiosis; Heterotrophic Processes; Nitrogen; Nitrites
PubMed: 37586428
DOI: 10.1016/j.biortech.2023.129681 -
Water Research Oct 2023Since the onset of the COVID-19 Pandemic, large amounts of chlorine-containing disinfectants have been used to interrupt the spread of SARS-CoV-2 and residual chlorine...
Since the onset of the COVID-19 Pandemic, large amounts of chlorine-containing disinfectants have been used to interrupt the spread of SARS-CoV-2 and residual chlorine eventually entered the hospital or municipal sewage treatment facilities. However, little is known about the effect of chlorine influx on the biological sewage treatment process. Here we investigated the effect of chlorine on the microbiome and the mechanism of microbial chlorine resistance in the activated sludge of the aerobic treatment process, using metagenomic and metatranscriptomic sequencing. We found that chlorine could negatively impact the aerobic treatment performance regarding nitrogen/COD removal with a dose-dependent effect, and the dual effects of chlorine dose and interaction time differentiated the microbial community in activated sludge. The decline of nitrogen/COD removal was attributed to the compressed activity of functional microorganisms, such as the ammonia oxidation bacteria, under chlorinated conditions, and the damage cannot be recovered in a short term. In addition, some microorganisms could survive in chlorinated conditions by up-regulating the chlorine resistance genes (CRGs) expression (approximately 1.5 times) and stimulating new CRGs expression. In particular, species Acinetobacter johnsonii could resist high concentrations of chlorine through various mechanisms, especially the overexpression of efflux pump function encoded by qac genes play a key role. Based on these results, considering the persistence of the epidemic and extensive use of chlorine disinfectants, it cannot be ignored that large amounts of residual chlorine are entering the biological treatment facility, and strictly de-chlorination measures or microbial chlorine resistance regulations before entering should be implemented.
Topics: Humans; Disinfectants; Chlorine; Sewage; Pandemics; COVID-19; SARS-CoV-2; Nitrogen
PubMed: 37572464
DOI: 10.1016/j.watres.2023.120453 -
Journal of Laboratory Physicians Sep 2023species has become a leading cause of nosocomial infections in recent years. The aim of the study was to establish the usefulness of matrix-assisted laser...
species has become a leading cause of nosocomial infections in recent years. The aim of the study was to establish the usefulness of matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS) for the identification of species with respect to conventional biochemical methods and MicroScan WalkAway 96 Plus system and to compare the antibiotic susceptibility test results Kirby-Bauer disk diffusion method with MicroScan WalkAway 96 Plus automated identification and antimicrobial susceptibility testing system. The study sample comprised 100 clinical isolates of species. They were all identified using MALDI-TOF MS and compared with other two identification systems. Comparison of categorical variables by Fisher's exact test or Pearson's chi-square test was done. All statistical tools were two tailed, and a significant level < 0.05 was used. All statistical tests were performed using SPSS v22.0 (Armonk IBM Corp., New York, United States). Cohen's kappa coefficients were also calculated and used as applicable. MALDI-TOF MS revealed 92 , 2 , 3 , and 1 each was identified as , , and . There was moderate agreement between identification by MicroScan WalkAway and MALDI-TOF, and substantial agreement between conventional biochemical tests and MALDI-TOF. We found that there was a 100% categorical agreement with respect to susceptibility of aminoglycosides (amikacin, gentamicin, tobramycin) and cephalosporins (ceftazidime, cefepime, cefotaxime) between disk diffusion method and MicroScan WalkAway 96 Plus system. Total of 16 errors were observed. Although MALDI-TOF MS could be useful to identify but not other species in the genus, it is a rapid, reliable method and can be routinely used in clinical laboratories.
PubMed: 37564221
DOI: 10.1055/s-0042-1760401 -
Scientific Reports Aug 2023Water supply suspension-restoration can occur frequently due to the overhauling of civil infrastructure in developing countries and the shutdown of commercial buildings...
Water supply suspension-restoration can occur frequently due to the overhauling of civil infrastructure in developing countries and the shutdown of commercial buildings during the pandemic. For comprehensive insights into the effects of water supply suspension-restoration, this study characterized the variations of the pathogen community composition of the tap water and their infection risk under different water supply scenarios. Metagenomic sequencing revealed a significant change of the human pathogen profiles, among which the most dominant pathogen changed from Pseudomonas aeruginosa (4.91%) to Acinetobacter johnsonii (0.59%). Furthermore, absolute quantification of pathogens by propidium-monoazide-qPCR revealed that the abundance of the three typical pathogens (Pseudomonas aeruginosa, Mycobacterium avium and Salmonella sp.) showed an increase of 2.44 log to 3.60 log immediately after water supply suspension-restoration and did not return to the normal level even after 2-h supply restoration, except for Pseudomonas aeruginosa. Quantitative microbial risk assessment suggested the infection risks of the three pathogens arising from direct utilization of tap water under stable water supply, including dermal exposure and oral intake, were all above the threshold of 10, and evidently increased after water supply suspension-restoration. This study warns us against the risk induced by the pathogens in tap water, especially after water supply suspension-restoration.
Topics: Humans; Water Supply; Water; Mycobacterium avium; Pseudomonas aeruginosa; Water Microbiology
PubMed: 37528119
DOI: 10.1038/s41598-023-39225-z -
Biodegradation Dec 2023The present study aimed to screen and optimize lipase production by the Antarctic strain Acinetobacter johnsonii Ant12 for lipid-rich wastewater treatment. Lipase...
The present study aimed to screen and optimize lipase production by the Antarctic strain Acinetobacter johnsonii Ant12 for lipid-rich wastewater treatment. Lipase production was successfully enhanced threefold through optimization of culture conditions. The optimum crude lipase activity was observed at 50 °C with high stability in a wide temperature range. The lipase also exhibited high activity and stability in the presence of solvents, metal ions, and surfactants. The crude lipase was used for the treatment of lipid-rich wastewater, which poses a significant challenge, as traditional removal methods are often inefficient or non-eco-friendly. In this study, bioaugmentation with Ant12 resulted in substantial lipid reduction in synthetic as well as real-world wastewater. Multiple linear regression analysis showed that lipid concentration and time were the most significant factors influencing lipid degradation. Bioaugmentation of real-world wastewater with Ant12 cells resulted in 84% removal of lipids in 72 h, while its crude lipase degraded 73.7% of lipids after 24 h. Thus, the specific rate of lipid degradation was higher for crude lipase (0.095/h) than the whole cell treatment (0.031/h). Economic analysis revealed that crude lipase production was much cheaper, faster and more eco-friendly than purified or partially purified lipase production, which justifies its use in wastewater treatment. The high activity of enzyme also implicates its application as a detergent additive. In our knowledge, it is the first study to establish A. johnsonii isolate from Antarctica for lipid-rich wastewater treatment.
Topics: Lipase; Wastewater; Antarctic Regions; Lipids; Temperature; Enzyme Stability; Hydrogen-Ion Concentration
PubMed: 37354270
DOI: 10.1007/s10532-023-10041-6 -
Food Science & Nutrition Jun 2023Mongolian butter and Tude are traditional high-fat dairy products produced in Xilin Gol, China, which have unique chemical and microbiological characteristics. Mongolian...
Mongolian butter and Tude are traditional high-fat dairy products produced in Xilin Gol, China, which have unique chemical and microbiological characteristics. Mongolian Tude is made from Mongolian butter, dreg, and flour. In this study, the traditional manufacturing process of Mongolian butter and Tude was investigated for the first time. Mongolian butter was characterized by high-fat content (99.38 ± 0.63%) and high acidity (77.09 ± 52.91°T), whereas Mongolian Tude was considered a high-fat (21.45 ± 1.23%) and high-protein (8.28 ± 0.65%) dairy product obtained by butter, dreg, and flour. Mongolian butter and Tude were proven to be safe for human consumption in terms of benzopyrene content. In addition, , , , coliforms, and aflatoxin M1 were not detected in the samples. Bacteria and molds were not isolated from Mongolian butter; in contrast, the total count of bacteria and molds in Mongolian Tude was within the range of 4.5 × 10 to 9.5 × 10 and 0 to 2.2 × 10, respectively. Moreover, (41.55%), (11.05%), (40.20%), and (12.90%) were the predominant bacterial and fungal genera, and (15.6%), (9.6%), (8.5%), (6.1%), (4.2%), (3.5%), (3.5%), (46.2%), (14.7%), and (11.7%) were the predominant species in the microbiota of Mongolian Tude. Thus, it can be stated that the microbiota of food products produced by different small families varied significantly. Collectively, the findings presented herein are the first report of chemical and microbiological characterization of products of geographical origin and highlight the need for standardization of manufacturing procedures of Mongolian butter and Tude in the future.
PubMed: 37324868
DOI: 10.1002/fsn3.3283 -
Ecotoxicology and Environmental Safety Jun 2023Nanoplastics and microbial pathogens are both widely distributed in the environment; however, their combined toxicity remains largely unclear. Using Caenorhabditis...
Exposure to polystyrene nanoparticles at predicted environmental concentrations enhances toxic effects of Acinetobacter johnsonii AC15 infection on Caenorhabditis elegans.
Nanoplastics and microbial pathogens are both widely distributed in the environment; however, their combined toxicity remains largely unclear. Using Caenorhabditis elegans as an animal model, we examined the possible effect of exposure to polystyrene nanoparticle (PS-NP) in Acinetobacter johnsonii AC15 (a bacterial pathogen) infected animals. Exposure to PS-NP at the concentrations of 0.1-10 μg/L significantly enhanced the toxicity of Acinetobacter johnsonii AC15 infection on lifespan and locomotion behaviors. In addition, after exposure to 0.1-10 μg/L PS-NP, the accumulation of Acinetobacter johnsonii AC15 in body of nematodes was also increased. Meanwhile, the innate immune response indicated by the increase of antimicrobial gene expressions in Acinetobacter johnsonii AC15 infected nematodes was suppressed by exposure to 0.1-10 μg/L PS-NP. Moreover, expressions of egl-1, dbl-1, bar-1, daf-16, pmk-1, and elt-2 governing the bacterial infection and immunity in Acinetobacter johnsonii AC15 infected nematodes were further inhibited by exposure to 0.1-10 μg/L PS-NP. Therefore, our data suggested the possible exposure risk of nanoplastic at predicted environmental concentrations in enhancing the toxic effects of bacterial pathogens on environmental organisms.
PubMed: 37315368
DOI: 10.1016/j.ecoenv.2023.115131 -
Frontiers in Immunology 2023Olfactory dysfunction (OD) is a debilitating symptom frequently reported by patients with chronic rhinosinusitis (CRS) and it is associated with a dysregulated sinonasal...
PURPOSE
Olfactory dysfunction (OD) is a debilitating symptom frequently reported by patients with chronic rhinosinusitis (CRS) and it is associated with a dysregulated sinonasal inflammation. However, little information is available about the effect of the inflammation-related nasal microbiota and related metabolites on the olfactory function in these patients. Therefore, the current study aimed to investigate the nasal microbiota-metabolites-immune interactions and their role in the pathogenesis of OD in CRS patients.
METHODS
23 and 19 CRS patients with and without OD, respectively, were enrolled in the present study. The "Sniffin' Sticks" was used to measure the olfactory function, while the metagenomic shotgun sequencing and the untargeted metabolite profiling were performed to assess the differences in terms of the nasal microbiome and metabolome between the two groups. The levels of nasal mucus inflammatory mediators were investigated by a multiplex flow Cytometric Bead Array (CBA).
RESULTS
A decreased diversity in the nasal microbiome from the OD group compared to the NOD group was evidenced. The metagenomic analysis revealed a significant enrichment of in the OD group, while , , and were significantly less represented (LDA value > 3, p < 0.05). The nasal metabolome profiles were significantly different between the OD and NOD groups ( < 0.05). The purine metabolism was the most significantly enriched metabolic subpathway in OD patients compared with NOD patients ( < 0.001). The expressions of IL-5, IL-8, MIP-1α, MCP-1, and TNF were statistically and significantly increased in the OD group ( < 0.05). All these data, including the dysregulation of the nasal microbiota, differential metabolites, and elevated inflammatory mediators in OD patients demonstrated a clear interaction relationship.
CONCLUSION
The disturbed nasal microbiota-metabolite-immune interaction networks may be implicated in the pathogenesis of OD in CRS patients and the underlying pathophysiological mechanisms need to be further investigated in future studies.
Topics: Humans; Rhinitis; Olfaction Disorders; Smell; Sinusitis; Chronic Disease; Inflammation; Microbiota
PubMed: 37292198
DOI: 10.3389/fimmu.2023.1159112 -
Frontiers in Microbiology 2023The co-existence of hydroxylamine (NHOH) and nitrite (NO -N) can aggravate the difficulty of wastewater treatment. The roles of hydroxylamine (NHOH) and nitrite (NO -N)...
The co-existence of hydroxylamine (NHOH) and nitrite (NO -N) can aggravate the difficulty of wastewater treatment. The roles of hydroxylamine (NHOH) and nitrite (NO -N) in accelerating the elimination of multiple nitrogen sources by a novel isolated strain of EN-J1 were investigated in this study. The results demonstrated that strain EN-J1 could eliminate 100.00% of NHOH (22.73 mg/L) and 90.09% of NO -N (55.32 mg/L), with maximum consumption rates of 1.22 and 6.75 mg/L/h, respectively. Prominently, the toxic substances NHOH and NO -N could both facilitate nitrogen removal rates. Compared with the control treatment, the elimination rates of nitrate (NO -N) and NO -N were enhanced by 3.44 and 2.36 mg/L/h after supplementation with 10.00 mg/L NHOH, and those of ammonium (NH -N) and NO -N were improved by 0.65 and 1.00 mg/L/h after the addition of 50.00 mg/L NO -N. Furthermore, the nitrogen balance results indicated that over 55.00% of the initial total nitrogen was transformed into gaseous nitrogen by heterotrophic nitrification and aerobic denitrification (HN-AD). Ammonia monooxygenase (AMO), hydroxylamine oxidoreductase (HAO), nitrate reductase (NR), and nitrite reductase (NIR), which are essential for HN-AD, were detected at levels of 0.54, 0.15, 0.14, and 0.01 U/mg protein, respectively. All findings confirmed that strain EN-J1 could efficiently execute HN-AD, detoxify NHOH and NO -N, and ultimately promote nitrogen removal rates.
PubMed: 37138626
DOI: 10.3389/fmicb.2023.1130512 -
Archives of Microbiology Mar 2023Cardiovascular complications due to thrombosis have become one of the main causes of death worldwide. The high cost and undesirable side effects of existing thrombolytic...
Cardiovascular complications due to thrombosis have become one of the main causes of death worldwide. The high cost and undesirable side effects of existing thrombolytic agents have led researchers to isolate potential strains that produce fibrinolytic enzymes for therapeutic applications. Fibrinolytic enzymes, especially of microbial origin, are recognized as potential therapeutic candidates for thrombosis. In this study, isolation, identification, and optimization of fibrinolytic protease enzyme-producing strains were performed using fermentative protein sources. Fibrinolytic protease-producing strains were selected by analyzing the isolated strains on skim milk agar medium. The selected strains were examined on blood agar and fibrin plate medium, and the ones showing high enzymatic activity were determined. The strain determined to have the highest activity was identified as Acinetobacter johnsonii TR01 by 16S rRNA analysis. The maximum fibrinolytic protease production of the strain occurred at 60 °C and pH 7.0. Under different medium conditions used for enzyme production, fructose was found to be the best carbon source, while yeast extract and peptone were the best nitrogen sources. It was observed that CaCl, KHPO, and MgSO components had a negative effect, while MnCl and ZnCHO components had a positive effect on enzyme production. The medium composition for maximum enzyme activity (8.30 IU/ml) determined by Response Surface Methodology was 14.22 g/L fructose, 11.190 g/L yeast extract, 14.22 g/L peptone, 0.5 g/L MnCl, and 0.5 g/L ZnCHO.
Topics: Humans; Peptide Hydrolases; Peptones; RNA, Ribosomal, 16S; Agar; Endopeptidases; Culture Media; Thrombosis
PubMed: 36961583
DOI: 10.1007/s00203-023-03486-z