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Journal of Agricultural and Food... Sep 2022In this study, the complex volatilome of maize silage samples conserved for 229 d, inoculated with () and (), is explored by means of advanced fingerprinting...
In this study, the complex volatilome of maize silage samples conserved for 229 d, inoculated with () and (), is explored by means of advanced fingerprinting methodologies based on comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry. The combined untargeted and targeted (UT) fingerprinting strategy covers 452 features, 269 of which were putatively identified and assigned within their characteristic classes. The high amounts of short-chain free fatty acids and alcohols were produced by fermentation and led to a large number of esters. The impact of fermentation was not clearly distinguishable from the control samples; however, had a strong and distinctive signature that was dominated by propionic acid and 1-propanol characteristic volatiles. The approach provides a better understanding of silage stabilization mechanisms against the degradative action of yeasts and molds during the exposure of silage to air.
Topics: 1-Propanol; Aerobiosis; Fatty Acids, Nonesterified; Lactobacillus; Lacticaseibacillus paracasei; Propionates; Silage; Zea mays
PubMed: 36103255
DOI: 10.1021/acs.jafc.2c03652 -
Proceedings of the National Academy of... Sep 2022Aerobic life is powered by membrane-bound enzymes that catalyze the transfer of electrons to oxygen and protons across a biological membrane. Cytochrome oxidase (CO)...
Aerobic life is powered by membrane-bound enzymes that catalyze the transfer of electrons to oxygen and protons across a biological membrane. Cytochrome oxidase (CO) functions as a terminal electron acceptor in mitochondrial and bacterial respiratory chains, driving cellular respiration and transducing the free energy from O reduction into proton pumping. Here we show that CO creates orientated electric fields around a nonpolar cavity next to the active site, establishing a molecular switch that directs the protons along distinct pathways. By combining large-scale quantum chemical density functional theory (DFT) calculations with hybrid quantum mechanics/molecular mechanics (QM/MM) simulations and atomistic molecular dynamics (MD) explorations, we find that reduction of the electron donor, heme , leads to dissociation of an arginine (Arg438)-heme D-propionate ion-pair. This ion-pair dissociation creates a strong electric field of up to 1 V Å along a water-mediated proton array leading to a transient proton loading site (PLS) near the active site. Protonation of the PLS triggers the reduction of the active site, which in turn aligns the electric field vectors along a second, "chemical," proton pathway. We find a linear energy relationship of the proton transfer barrier with the electric field strength that explains the effectivity of the gating process. Our mechanism shows distinct similarities to principles also found in other energy-converting enzymes, suggesting that orientated electric fields generally control enzyme catalysis.
Topics: Aerobiosis; Electron Transport; Electron Transport Complex IV; Oxygen; Protons; Water
PubMed: 36095184
DOI: 10.1073/pnas.2207761119 -
International Journal of Environmental... Sep 2022The aerobic granulation, pollutant removal, and microbial community in real textile wastewater (TWW) treatment were compared using conventional activated sludge (CAS)...
The aerobic granulation, pollutant removal, and microbial community in real textile wastewater (TWW) treatment were compared using conventional activated sludge (CAS) and preformed aerobic granular sludge (AGS) in synthetic wastewater as seed in two reactors, reactor-1 (R1) and reactor-2 (R2), respectively. The results showed that complete granulation was achieved in R1 (sludge volume index at 5 min (SVI) and 30 min (SVI): 19.4 mL/g; granule size: 210 μm) within 65 days, while it only required 28 days in R2 (SVI and SVI: 27.3 mL/g; granule size: 496 μm). The removal of COD, NH-N and TN in R1 (49.8%, 98.8%, and 41.6%) and R2 (53.6%, 96.9%, and 40.8%) were comparable in 100% real TWW treatment, but stable performance was achieved much faster in R2. The real TWW had an inhibitory effect on heterotrophic bacteria activity, but it had no inhibition on ammonia-oxidizing bacteria activity. AGS with a larger particle size had a higher microbial tolerance to real TWW. Furthermore, filamentous in the AGS in R2 disappeared when treating real TWW, leading to the improvement of sludge settleability. Thus, seeding preformed AGS is suggested as a rapid start-up method for a robust AGS system in treating real TWW.
Topics: Aerobiosis; Bioreactors; Environmental Pollutants; Microbiota; Nitrogen; Sewage; Textiles; Waste Disposal, Fluid; Wastewater
PubMed: 36078654
DOI: 10.3390/ijerph191710940 -
The Science of the Total Environment Dec 2022Wastewater treatment plants act as microplastic (MPs) sinks and secondary MP pollution sources. Little is known about the effect of MPs on biomass and the efficiency of...
Wastewater treatment plants act as microplastic (MPs) sinks and secondary MP pollution sources. Little is known about the effect of MPs on biomass and the efficiency of biological wastewater treatment. This study assessed the impact of polyethylene (PE) MPs concentrations (1, 10, 50 mg/L) in wastewater on biological conversions and extracellular polymeric substances (EPS) production (including alginate) in aerobic granular sludge (AGS). PE MPs did not worsen the efficiency of biological treatment but stimulated the production of EPS and alginate in AGS. The alginate content increased from 238.7 ± 4.4 mg/g MLSS in control to 441.6 ± 13.8 mg/g MLSS at the highest PE load in wastewater. The presence of MP changed AGS morphology and worsened the settling properties of biomass, causing biomass washout from the reactors. At the highest PE load in wastewater, the biomass concentration in the reactor effluent was over 2.8 times higher than in the control.
Topics: Aerobiosis; Alginates; Bioreactors; Extracellular Polymeric Substance Matrix; Microplastics; Plastics; Polyethylene; Sewage; Waste Disposal, Fluid; Wastewater
PubMed: 36028039
DOI: 10.1016/j.scitotenv.2022.158208 -
Microorganisms Jul 2022Infections caused by Mycobacterium abscessus (Mab), an environmental non-tuberculous mycobacterium, are difficult to eradicate from patients with pulmonary diseases such...
Infections caused by Mycobacterium abscessus (Mab), an environmental non-tuberculous mycobacterium, are difficult to eradicate from patients with pulmonary diseases such as cystic fibrosis and bronchiectasis even after years of antibiotic treatments. In these people, the low oxygen pressure in mucus and biofilm may restrict Mab growth from actively replicating aerobic (A) to non-replicating hypoxic (H) stages, which are known to be extremely drug-tolerant. After the exposure of Mab A and H cells to drugs, killing was monitored by measuring colony-forming units (CFU) and regrowth in liquid medium (MGIT 960) of 1-day-old A cells (A1) and 5-day-old H cells (H5). Mab killing was defined as a lack of regrowth of drug-exposed cells in MGIT tubes after >50 days of incubation. Out of 18 drugs tested, 14-day treatments with bedaquiline-amikacin (BDQ-AMK)-containing three-drug combinations were very active against A1 + H5 cells. However, drug-tolerant cells (persisters) were not killed, as shown by CFU curves with typical bimodal trends. Instead, 56-day treatments with the nitrocompounds containing combinations BDQ-AMK-rifabutin-clarithromycin-nimorazole and BDQ-AMK-rifabutin-clarithromycin-metronidazole-colistin killed all A1 + H5 Mab cells in 42 and 56 days, respectively, as shown by lack of regrowth in agar and MGIT medium. Overall, these data indicated that Mab persisters may be killed by appropriate drug combinations.
PubMed: 35889140
DOI: 10.3390/microorganisms10071421 -
International Journal of Environmental... Jul 2022Improving treatment efficiency and reducing investment and operating costs make aerobic granular sludge technology (AGS) a promising technology for treating aquaculture...
Improving treatment efficiency and reducing investment and operating costs make aerobic granular sludge technology (AGS) a promising technology for treating aquaculture wastewater. The development of continuous flow reactors (CFRs) has become a new direction in the research of AGS. This study clarifies the granulation effect, hydrodynamic behavior and particle separation of three different CFRs (R1 to R3). The established CFD model was able to explain the hydrodynamic behavior in all three CFRs; in particular, R3 performed the best from the perspective of hydrodynamic behavior due to its abundant turbulence. In addition, the optimal baffle distance and baffle angle of R3 were simulated to be 40 mm and 60°, respectively, due to them providing the best turbulent flow and particle separation effect. However, an overlarge baffle angle could weaken the turbulent pattern in the reactor. The retention time distribution further confirmed the reasonability of these optimal parameters with the highest effective volume ratio of 0.82. In short, this study gives an instruction for exploring the rapid formation mechanism of AGS in a CFR to promote its engineering application.
Topics: Aerobiosis; Bioreactors; Hydrodynamics; Sewage; Waste Disposal, Fluid
PubMed: 35886165
DOI: 10.3390/ijerph19148306 -
Medical Mycology Aug 2022This study explores the growth of bacterial, fungal, and interkingdom biofilms under aerobiosis or microaerobic conditions and the effect of ozonated sunflower oil on...
UNLABELLED
This study explores the growth of bacterial, fungal, and interkingdom biofilms under aerobiosis or microaerobic conditions and the effect of ozonated sunflower oil on these biofilms. Candida species and Streptococcus mutans were used to study this interaction due to their importance in oral health and disease as these microorganisms display a synergistic relationship that manifests in the onset of caries and tooth decay. Biofilms were developed in a 96-well microtiter plate at 37ºC for 24 h, under aerobiosis or microaerobic conditions, and treated with ozonated oil for 5 to 120 min. All the microorganisms formed biofilms in both oxygenation conditions. Scanning electron microscopy was used to visualize biofilm morphology. Rodent experiments were performed to verify the oil-related toxicity and its efficacy in oral candidiasis. The growth of all Candida species was increased when co-cultured with S. mutans, whilst the growth of bacterium was greater only when co-cultured with C. krusei and C. orthopsilosis under aerobiosis and microaerobic conditions, respectively. Regardless of the oxygenation condition, ozonated oil significantly reduced the viability of all the tested biofilms and infected mice, showing remarkable microbicidal activity as corroborated with confocal microscopy and minimal toxicity. Thus, ozonated oil therapy can be explored as a strategy to control diseases associated with these biofilms especially in the oral cavity.
LAY SUMMARY
We demonstrated that ozonated sunflower oil is effective at killing the biofilms formed by Candida species, by the bacterium Streptococcus mutans, or by both micoorganisms that can interact in the oral cavity, making it a potential therapeutic option for the treatment of these infections.
Topics: Animals; Biofilms; Candida; Candida albicans; Mice; Streptococcus mutans; Sunflower Oil
PubMed: 35869980
DOI: 10.1093/mmy/myac055 -
Animal Bioscience Dec 2022The primary goal was to identify the effectiveness of chemical or biological additives in delaying the deterioration of early-harvested wilted rye silage after exposure...
OBJECTIVE
The primary goal was to identify the effectiveness of chemical or biological additives in delaying the deterioration of early-harvested wilted rye silage after exposure to air.
METHODS
Rye harvested as a whole plant at the early heading stage was wilted for 24 h. The wilted forage was divided into treatments including sodium diacetate (SDA) at 3 (SDA3) and 6 g/kg (SDA6), Lactobacillus plantarum (LP), L. buchneri (LB), or their equal mixture (LP+LB) at 1×106 colony-forming unit/g fresh matter.
RESULTS
After 60 d of conservation in 20-L silos, lactic acid was greater in LP and LP+LB silages than other treatments (102 vs 90.2 g/kg dry matter [DM]). Acetic acid was greatest in SDA6 (32.0 g/kg DM) followed by LB (26.1 g/kg DM) and was lowest in LP treatment (4.73 g/kg DM). Silage pH was lower with microbial inoculation and the lowest and highest values were observed in LP and untreated silages, respectively. After 60 d, neutral detergent fiber concentration was lowest in SDA6 silages, resulting in the greatest in vitro DM digestibility (846 g/kg DM). Aerobic stability was longest in SDA6 (176 h) followed by LB treatment (134 h). Instability after aerobiosis was greatest in LP silages (68 h), about 8 h less than untreated silages. After aerobic exposure, yeast and mold numbers were lowest in SDA6 silages, resulting in DM loss minimization. Exhaustion of acetic acid and lactic acid after aerobic exposure was lowest with SDA6 but greatest with untreated and LP silages.
CONCLUSION
Treatment of early-cut wilted rye forage with SDA at 6 g/kg resulted in silages with higher feeding value and fermentation quality, and substantially delayed deterioration after aerobic exposure, potentially qualifying SDA at this load for promotion of silage quality and delaying aerobic spoilage of early-harvested (low DM) rye forage.
PubMed: 35798047
DOI: 10.5713/ab.22.0150 -
Scientific Reports Jun 2022Himalayan ecosystem is characterized by its fragile climate with rich repositories of biodiversity. Waste collection and disposal are becoming increasingly difficult due...
Deciphering waste bound nitrogen by employing psychrophillic Aporrectodea caliginosa and priming of coprolites by associated heterotrophic nitrifiers under high altitude Himalayas.
Himalayan ecosystem is characterized by its fragile climate with rich repositories of biodiversity. Waste collection and disposal are becoming increasingly difficult due to topographical variations. Aporrectodea caligenosa, a versatile psychrophillic soil dweller, is a useful biocatalyst with potent bio-augmented capability for waste treatment at low temperatures. Microcosm experiments were conducted to elucidate the comprehensive nature of biogenic nitrogen transformation to NH and NO produced by coupling of earthworm-microbes. Higher biogenic recovery of NH-N from coprolites of garden soil (47.73 ± 1.16%) and Himalayan goat manure (86.32 ± 0.92%) with an increment of 14.12 and 47.21% respectively over their respective control (without earthworms) with a linear decline beyond 4th week of incubation was reported. NO-N recovery progressively sustained in garden soil and goat manure coprolites during entire incubation with highest 81.81 ± 0.45 and 87.20 ± 1.08 µg-N gdry weight recorded in 6th and 5th week of incubation respectively and peak increments as 38.58 and 53.71% relative to respective control (without earthworms). Declined NH-N in coprolites at low temperature (15.0 ± 2.0 °C) evidenced increased nitrification rates by taking over the process by abundant nitrifying microbes. Steady de-nitrification with progressive incubation on an average was 16.95 ± 0.46 ng-N g per week and 21.08 ± 0.87 ng-N g per week compared to 14.03 ± 0.58 ng-N g per week and 4.50 ± 0.31 ng-N g per week in respective control treatments. Simultaneous heterotrophic nitrification and aerobic denitrification (SHNAD) was found to be a prominent bioprocess at low temperature that resulted in high and stable total nitrogen and nitrate accumulation from garden soil and goat manure with relative recovery efficiency of 11.12%, 14.97% and 14.20%; 19.34%. A. caligenosa shows promising prospects for mass applicability in biogenic N removal from manure of Himalayan goat.
Topics: Aerobiosis; Altitude; Animals; Denitrification; Ecosystem; Heterotrophic Processes; Manure; Nitrification; Nitrogen; Oligochaeta; Soil; Wastewater
PubMed: 35688921
DOI: 10.1038/s41598-022-12972-1 -
Journal of Dairy Science Jun 2022Silage inoculants are commonly used as a tool to improve the fermentation and aerobic stability of corn silage fed to dairy cows. However, their effectiveness can be...
Silage inoculants are commonly used as a tool to improve the fermentation and aerobic stability of corn silage fed to dairy cows. However, their effectiveness can be inconsistent. Our objective was to determine the effect of the dry matter (DM) content of freshly chopped whole-plant corn on its microbial community as affected by an inoculant containing Lentilactobacillus hilgardii, Lentilactobacillus buchneri, and Pediococcus pentosaceus on improving the aerobic stability of silage. Whole-plant corn was harvested at low (31.80%, LDM), medium (33.32%, MDM), or high (39.44%, HDM) DM content and treated with nothing (CTR) or an inoculant (INO) containing L. hilgardii CNCM I-4785 at 150,000 cfu/g fresh forage, L. buchneri NCIMB 40788 at 150,000 cfu/g fresh forage, P. pentosaceus NCIMB12455 at 100,000 cfu/g of fresh forage, β-glucanase (5,750 IU/g), and xylanase (30,000 IU/g) and ensiled for 20 and 60 d. Data were analyzed as a completely randomized design in a 3-by-2 factorial arrangement of treatments. Fresh LDM forage had a higher concentration of reducing sugars, a less rich, diverse, and even bacterial community, and greater relative abundance of Saccharomycetales than MDM and HDM forages. Silages at 20 and 60 d, inoculated LDM had a more modest proliferation of culturable lactic acid bacteria than inoculated MDM. At 20 d, regardless of treatment, LDM had greater concentrations of lactic and acetic acids. Also at 20 d, LDM had lower numbers of culturable yeasts but greater relative abundance of Enterobacteriaceae than MDM and HDM. For silage at 20 d, HDM silage was more aerobically stable than LDM and MDM and inoculation improved aerobic stability 1.8-fold compared with CTR. For silage at 60 d, there was an interaction between DM content and inoculation. The improvements in stability by inoculation, compared with CTR, were greater in MDM (261 vs. 41 h) and HDM (320 vs. 66 h) silages than in LDM (85 vs. 46 h). The lower DM content and possible slower pH decline in LDM might have facilitated the development of undesirable bacteria and coupled with its greater concentration of reducing sugars and lactic and acetic acids, which are substrates for aerobic microorganisms, might explain the more modest improvements in aerobic stability from inoculation in LDM compared with MDM and HDM. Our findings suggest that the DM content of whole-plant corn affected its epiphytic microbial community and the effectiveness of the inoculant, which improved aerobic stability at all DM but to a greater extent in HDM and MDM than in LDM, especially after 60 d of ensiling.
Topics: Aerobiosis; Agricultural Inoculants; Animals; Bacteria; Cattle; Female; Fermentation; Microbiota; Silage; Sugars; Zea mays
PubMed: 35465996
DOI: 10.3168/jds.2021-21515