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The Science of the Total Environment Aug 2021Anthropogenic nutrients released into water induce eutrophication and threaten aquatic life and human health. In this study, an Fe anode coagulation cell with...
Anthropogenic nutrients released into water induce eutrophication and threaten aquatic life and human health. In this study, an Fe anode coagulation cell with nitrification and denitrification biocathodes was constructed for power generation and algae and nutrient removal. The nitrification and denitrification biocathodes achieved maximum power densities of 6.0 and 6.6 W/m, respectively. The algae (99.2 ± 0.5%), phosphate (97.4 ± 0.6%), and ammonia (23.1 ± 0.2%) were removed by a spontaneous electrocoagulation process in the anode chamber. In the nitrification biocathode chamber, 95.3 ± 1.4% of the ammonia was oxidized within 6 h, and 88.2 ± 2.5% of the nitrate was removed in 10 h in the denitrification biocathode chamber. The microbial community analysis revealed that ammonia removal was attributed to nitrifying bacteria, including Acinetobacter sp., Phycisphaera sp., and Nitrosomonas sp., and the dominant denitrifying bacteria in the denitrifying biocathode chamber were Planococcus sp., Exiguobacterium sp., and Lysinibacillus sp. In this study, the combination of Fe anodes and biocathodes is shown to afford an efficient method for the simultaneous algae and nutrient removal and power generation.
Topics: Bioelectric Energy Sources; Bioreactors; Denitrification; Electricity; Humans; Iron; Nitrification; Nitrogen; Wastewater; Water Purification
PubMed: 33838382
DOI: 10.1016/j.scitotenv.2021.146436 -
Marine Drugs Mar 2021With the widespread occurrence of aquaculture diseases and the broad application of antibiotics, drug-resistant pathogens have increasingly affected aquatic animals'...
With the widespread occurrence of aquaculture diseases and the broad application of antibiotics, drug-resistant pathogens have increasingly affected aquatic animals' health. Marine probiotics, which live under high pressure in a saltwater environment, show high potential as a substitute for antibiotics in the field of aquatic disease control. In this study, twenty strains of non-hemolytic bacteria were isolated from the intestine of wild oysters and perch, and a model of infected by was established. Based on the model, ML1206, which showed a 99% similarity of 16S rRNA sequence to , was selected as a potential marine probiotic, with strong antibacterial capabilities and great acid and bile salt tolerance, to protect from being damaged by . Combined with plate counting and transmission electron microscopy, it was found that strain ML1206 could significantly inhibit colonization in the intestinal tract of . Acute oral toxicity tests in mice showed that ML1206 was safe and non-toxic. The real-time qPCR results showed a higher expression level of genes related to the antibacterial peptide () and detoxification (, , and ) in the group of protected by ML1206 compared to the control group. It is speculated that ML1206, as a potential probiotic, may inhibit the infection caused by through stimulating to secrete antibacterial effectors and detoxification proteins. This paper provides a new direction for screening marine probiotics and an experimental basis to support the potential application of ML1206 as a marine probiotic in aquaculture.
Topics: Animals; Aquaculture; Caenorhabditis elegans; Female; Intestines; Male; Mice; Mice, Inbred ICR; Ostreidae; Planococcaceae; Probiotics; RNA, Ribosomal, 16S; Survival; Vibrio; Vibrio Infections
PubMed: 33809116
DOI: 10.3390/md19030150 -
International Microbiology : the... Aug 2021Sabkhas in Kuwait are unique hypersaline marine environments under-explored for bacterial community composition and bioprospecting. The 16S rRNA sequence analysis of 46...
Sabkhas in Kuwait are unique hypersaline marine environments under-explored for bacterial community composition and bioprospecting. The 16S rRNA sequence analysis of 46 isolates with distinct morphology from two Kuwait sabkhas recovered 11 genera. Phylum Firmicutes dominated these isolates, and Bacillus (32.6%) was recovered as the dominant genera, followed by Halococcus (17.4%). These isolates were moderately halophilic, and some of them showed tolerance and growth at extreme levels of salt (20%), pH (5 and/or 11), and temperature (55 °C). A higher percentage of isolates harbored protease (63.0), followed by DNase (41.3), amylase (41.3), and lipase (32.6). Selected isolates showed antimicrobial activity against E. faecalis and isolated Halomonas shengliensis, and Idiomarina piscisalsi harbored gene coding for dNDP-glucose 4,6-dehydratase (Glu 1), indicating their potential to produce biomolecules with deoxysugar moieties. Palmitic acid or oleic acid was the dominant fatty acid, and seven isolates had some polyunsaturated fatty acids (linolenic or γ-linolenic acid). Interestingly, six isolates belonging to Planococcus and Oceanobacillus genus produced squalene, a bioactive isoprenoid molecule. Their content increased 30-50% in the presence of Terbinafine. The potential bioactivities and extreme growth conditions make this untapped bacterial diversity a promising candidate for future bioprospecting studies.
Topics: Anti-Infective Agents; Antineoplastic Agents; Bacillus; Bacteria; Bacterial Proteins; Biodiversity; Bioprospecting; DNA, Bacterial; Enzymes; Fatty Acids; Firmicutes; Geologic Sediments; Halococcus; Kuwait; Phylogeny; Planococcaceae; RNA, Ribosomal, 16S; Salinity; Squalene; Water Microbiology
PubMed: 33755814
DOI: 10.1007/s10123-021-00173-1 -
Scientific Reports Mar 2021Dwarf bunt of wheat, which is caused by Tilletia controversa J.G. Kühn, is a soil-borne disease which may lead up to an 80% loss of yield together with degradation of...
Dwarf bunt of wheat, which is caused by Tilletia controversa J.G. Kühn, is a soil-borne disease which may lead up to an 80% loss of yield together with degradation of the quality of the wheat flour by production of a fishy smell. In this study, high-throughput sequencing technology was employed to characterize the microbial composition of wheat tissues (roots, spikes, first stem under the ear, and stem base) and rhizosphere soil of wheat varieties that are resistant and susceptible to T. controversa. We observed that the soil fungal community abundance and diversity were higher in resistant varieties than in susceptible varieties in both inoculated and uninoculated wheat, and the abundances of Sordariomycetes and Mortierellomycetes increased in the resistant varieties infected with T. controversa, while the abundances of Dothideomycetes and Bacteroidia increased in the susceptible varieties. Regarding the bacteria present in wheat tissues, the abundances of Chloroflexi, Bacteroidetes, Gemmatimonadetes, Verrucomicrobia and Acidobacteria in the ear and the first stem under the ear were higher than those in other tissues. Our results indicated that the abundances of Sordariomycetes, Mortierellomycetes, Leotiomycetes, Chryseobacterium and Massilia were higher in T. controversa-infected resistant varieties than in their controls, that Dothideomycetes, Bacteroidia, Nocardioides and Pseudomonas showed higher abundances in T. controversa-infected susceptible varieties, and that Curtobacterium, Exiguobacterium, Planococcus, and Pantoea may have higher abundances in both T. controversa-infected susceptible and resistant varieties than in their own controls.
Topics: Bacteria; Biodiversity; Endophytes; Fungi; Microbiota; Plant Diseases; Plant Leaves; Plant Roots; Plant Stems; Principal Component Analysis; Rhizosphere; Sequence Analysis, DNA; Soil Microbiology; Triticum
PubMed: 33707584
DOI: 10.1038/s41598-021-85281-8 -
Microbial Biotechnology May 2021Microbially induced calcite precipitation (MICP), secreted through biological metabolic activity, secured an imperative position in remedial measures within the...
Microbially induced calcite precipitation (MICP), secreted through biological metabolic activity, secured an imperative position in remedial measures within the construction industry subsequent to ecological, environmental and economical returns. However, this contemporary recurrent healing system is susceptible to microbial depletion in the highly alkaline cementitious environment. Therefore, researchers are probing for alkali resistant calcifying microbes. In the present study, alkaliphilic microbes were isolated from different soil sources and screened for probable CaCO precipitation. Non-ureolytic pathway (oxidation of organic carbon) was adopted for calcite precipitation to eliminate the production of toxic ammonia. For this purpose, calcium lactate Ca(C H O ) and calcium acetate Ca(CH COO) were used as CaCO precipitation precursors. The quantification protocol for precipitated CaCO was established to select potent microbial species for implementation in the alkaline cementitious systems as more than 50% of isolates were able to precipitate CaCO . Results suggested 80% of potent calcifying strains isolated in this study, portrayed higher calcite precipitation at pH 10 when compared to pH 7. Ten superlative morphologically distinct isolates capable of CaCO production were identified by 16SrRNA sequencing. Sequenced microbes were identified as species of Bacillus, Arthrobacter, Planococcus, Chryseomicrobium and Corynebacterium. Further, microstructure of precipitated CaCO was inspected through scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermal gravimetric (TG) analysis. Then, the selected microbes were investigated in the cementitious mortar to rule out any detrimental effects on mechanical properties. These strains showed maximum of 36% increase in compressive strength and 96% increase in flexural strength. Bacillus, Arthrobacter, Corynebacterium and Planococcus genera have been reported as CaCO producers but isolated strains have not yet been investigated in conjunction with cementitious mortar. Moreover, species of Chryseomicrobium and Glutamicibacter were reported first time as calcifying strains.
Topics: Bacillus; Bacteria; Calcium Carbonate; Chemical Precipitation; Feasibility Studies
PubMed: 33629805
DOI: 10.1111/1751-7915.13752 -
Frontiers in Microbiology 2021Protease-producing bacteria play vital roles in degrading organic matter of aquaculture system, while the knowledge of diversity and bacterial community structure of...
Protease-producing bacteria play vital roles in degrading organic matter of aquaculture system, while the knowledge of diversity and bacterial community structure of protease-producing bacteria is limited in this system, especially in the tropical region. Herein, 1,179 cultivable protease-producing bacterial strains that belonged to Actinobacteria, Firmicutes, and Proteobacteria were isolated from tropical aquaculture systems, of which the most abundant genus was , followed by . The diversity and relative abundance of protease-producing bacteria in sediment were generally higher than those in water. Twenty-one genera from sediment and 16 genera from water were identified, of which dominated by in both and dominated by in water were the dominant genera. The unique genera in sediment or water accounted for tiny percentage may play important roles in the stability of community structure. Eighty isolates were clustered into four clusters (ET-1-ET-4) at 58% of similarity by ERIC-PCR (enterobacterial repetitive intergenic consensus-polymerase chain reaction), which was identified as a novel branch of . Additionally, strains belonged to ET-3 and ET-4 were detected in most aquaculture ponds without outbreak of epidemics, indicating that these protease-producing bacteria may be used as potential beneficial bacteria for wastewater purification. Environmental variables played important roles in shaping protease-producing bacterial diversity and community structure in aquaculture systems. In sediment, dissolved oxygen (DO), chemical oxygen demand (COD), and salinity as the main factors positively affected the distributions of dominant genus () and unique genera ( and ), whereas temperature negatively affected that of (except ). In water, as unique genus and were negatively affected by NO -N and NO -N, respectively, whereas pH as the main factor positively affected the distribution of . These findings will lay a foundation for the development of protease-producing bacterial agents for wastewater purification and the construction of an environment-friendly tropical aquaculture model.
PubMed: 33613508
DOI: 10.3389/fmicb.2021.638129 -
Life (Basel, Switzerland) Jan 2021(1) Background: Future missions to potentially habitable places in the Solar System require biochemistry-independent methods for detecting potential alien life forms....
(1) Background: Future missions to potentially habitable places in the Solar System require biochemistry-independent methods for detecting potential alien life forms. The technology was not advanced enough for onboard machine analysis of microscopic observations to be performed in past missions, but recent increases in computational power make the use of automated in-situ analyses feasible. (2) Methods: Here, we present a semi-automated experimental setup, capable of distinguishing the movement of abiotic particles due to Brownian motion from the motility behavior of the bacteria . Supervised machine learning algorithms were also used to specifically identify these species based on their characteristic motility behavior. (3) Results: While we were able to distinguish microbial motility from the abiotic movements due to Brownian motion with an accuracy exceeding 99%, the accuracy of the automated identification rates for the selected species does not exceed 82%. (4) Conclusions: Motility is an excellent biosignature, which can be used as a tool for upcoming life-detection missions. This study serves as the basis for the further development of a microscopic life recognition system for upcoming missions to Mars or the ocean worlds of the outer Solar System.
PubMed: 33445805
DOI: 10.3390/life11010044 -
PeerJ 2020Numerous bacteria entered the viable but non-culturable state due to the stresses of dry and salt in soils. YeaZ of Gram-negative bacteria is a resuscitation promoting...
Numerous bacteria entered the viable but non-culturable state due to the stresses of dry and salt in soils. YeaZ of Gram-negative bacteria is a resuscitation promoting factor (Rpf) homologous protein could resuscitate bacteria of natural environment in VBNC state. To investigate the promoting effect of YeaZ on the isolation of viable but non-culturable (VBNC) bacteria from soil samples in extreme environments, the recombinant YeaZ of was prepared and added to the soil samples from volcanic soil and saline soil in Northwest China. The study has shown that YeaZ can promote the recovery and growth of soil microorganisms, and the number of cultivable bacteria in volcanic and saline soil has increased from 0.17 × 10 and 2.03 × 10 cfu⋅ml to 1.00 × 10 and 5.55 × 10 cfu⋅ml, respectively. The 16S rDNA gene sequencing and phylogenetic analysis showed that YeaZ played an essential role in the increase of composition and diversity of bacteria. A total of 13 bacterial strains were isolated from the volcanic soil samples, which belong to phyla Actinobacteria, Firmicutes and Gamma-proteobacteria. Four species, including , , and were found in the control group, while , , , , and were isolated from the treatment groups (addition of YeaZ). Twenty-one strains were isolated from the saline soil samples, including eight species from the control group and thirteen species from the treatment groups, among which nine species were only found, including , , , , , , , and . The results suggest that addition of YeaZ to soil samples can promote the recovery of VBNC. This method has the implications for the discovery of VBNC bacteria that have potential environmental functions.
PubMed: 33391864
DOI: 10.7717/peerj.10342 -
Journal of Environmental Health Science... Dec 2020The aim of the present work was to assess the electrogenic activity of bacteria from hydrothermal vent sediments achieved under sulfate reducing (SR) conditions in a...
PURPOSE
The aim of the present work was to assess the electrogenic activity of bacteria from hydrothermal vent sediments achieved under sulfate reducing (SR) conditions in a microbial fuel cell design with acetate, propionate and butyrate as electron donors.
METHODS
Two different mixtures of volatile fatty acids (VFA) were evaluated as the carbon source at two chemical oxygen demand (COD) proportions. The mixtures of VFA used were: acetate, propionate and butyrate COD: 3:0.5:0.5 (stage 1) and acetate - butyrate COD: 3.5:0.5 (stage 2). Periodical analysis of sulfate (SO ), sulfide (HS) and COD were conducted to assess sulfate reduction (SR) and COD removal along with measurements of voltage and current to assess the global performance of the consortium in the system.
RESULTS
Percentage of SR was of 97.5 ± 0.7 and 74.3 ± 1.5% for stage 1 and 2, respectively. The % COD removal was of 91 ± 2.1 and 75.3 ± 9.6 for stage 1 and 2, respectively. Although SR and COD removal were higher at stage 1, in regards of energy, stage 2 presented higher current and power densities and Coulombic efficiency as follows: 741.7 ± 30.5 μA/m, 376 ± 34.4 μW/m and 5 ± 2.7%, whereas for stage 1 these values were: 419 ± 71 μA/m, 52.7 ± 18 μW/m and 0.02%, respectively. A metagenomic analysis - stage 2 - in the anodic chamber, demonstrated that SR was due to (), and and the electrogenic microorganisms were , , , , and families and .
CONCLUSIONS
It was demonstrated that microorganisms prevenient from hydrothermal vent sediments adapted to a microbial fuel cell system are able to generate electricity coupled to 74.3 ± 1.5 and 75.3 ± 9.6% of SR and COD removal respectively, with a mixture of acetate - butyrate.
PubMed: 33312634
DOI: 10.1007/s40201-020-00537-1 -
Frontiers in Microbiology 2020This study aims at exploiting salinity stress as an innovative, simple, and cheap method to enhance the production of antioxidant metabolites and enzymes from bacteria...
This study aims at exploiting salinity stress as an innovative, simple, and cheap method to enhance the production of antioxidant metabolites and enzymes from bacteria for potential application as functional additives to foods and pharmaceuticals. We investigated the physiological and biochemical responses of four bacterial isolates, which exhibited high tolerance to 20% NaCl (wt/vol), out of 27 bacterial strains isolated from Aushazia Lake, Qassim region, Saudi Arabia. The phylogenetic analysis of the 16S rRNA genes of these four isolates indicated that strains ST1 and ST2 belong to genus , whereas strains ST3 and ST4 belong to genus . Salinity stress differentially induced oxidative damage, where strains ST3 and ST4 showed increased lipid peroxidation, lipoxygenase, and xanthine oxidase levels. Consequently, high antioxidant contents were produced to control oxidative stress, particularly in ST3 and ST4. These two strains showed increased glutathione cycle, phenols, flavonoids, antioxidant capacity, catalase, and/or superoxide dismutase (SOD). Interestingly, the production of glutathione by strains was some thousand folds greater than by higher plants. On the other hand, the induction of antioxidants in ST1 and ST2 was restricted to phenols, flavonoids, peroxidase, glutaredoxin, and/or SOD. The hierarchical analysis also supported strain-specific responses. This is the first report that exploited salinity stress for promoting the production of antioxidants from bacterial isolates, which can be utilized as postbiotics for promising applications in foods and pharmaceuticals.
PubMed: 33042068
DOI: 10.3389/fmicb.2020.561816