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Microbiologically induced calcite precipitation (MICP), as a newly developing bioremediation technology, could redeem heavy metal contamination in diverse scenarios. In this study, MICP bacterium Sporosarcina ureilytica ML-2 was employed to suppress the pollution of Pb, Cd and Zn in municipal sludge nutrient soil. After MICP remediation, the exchangeable Cd and Zn in sludge nutrient soil were correspondingly reduced by 31.02 % and 6.09 %, while the carbonate-bound Pb, Cd and Zn as well as the residual fractions were increased by 16.12 %, 6.63 %, 13.09 % and 6.10 %, 45.70 %, 3.86 %, respectively. In addition, the extractable Pb, Cd and Zn either by diethylenetriaminepentaacetic acid (DTPA) or toxicity characteristic leaching procedure (TCLP) in sludge nutrient soil were significantly reduced. These results demonstrated that the bio-calcite generated via MICP helped to immobilize heavy metals. Furthermore, MICP treatment improved the abundance of functional microorganisms related to urea cycle, while reduced the overall abundance of metal resistance genes (MRGs) and antibiotic resistance genes (ARGs). This work confirmed the feasibility of MICP in remediation of heavy metal in sludge nutrient soil, which expanded the application field of MICP and provided a promising way for heavy metal pollution management.
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Biodegradación Ambiental , Carbonato de Calcio , Metales Pesados , Aguas del Alcantarillado , Contaminantes del Suelo , Sporosarcina , Carbonato de Calcio/química , Contaminantes del Suelo/análisis , Contaminantes del Suelo/metabolismo , Aguas del Alcantarillado/microbiología , Metales Pesados/análisis , Sporosarcina/metabolismo , Sporosarcina/genética , Microbiología del Suelo , Precipitación QuímicaRESUMEN
As an important source of malodor, the odor gases emitted from public toilet significantly interfered the air quality of living surroundings, resulting in environmental problem which received little attention before. Thus, this paper explored the odor release pattern of latrine feces and deodorization effect with composited microbial agent in Chengdu, China. The odor release rules were investigated in sealed installations with a working volume of 9 L for 20 days. The odor units (OU), ammonia (NH3), hydrogen sulfide (H2S) and total volatile organic compounds (TVOC) were selected to assess the release of malodorous gases under different temperature and humidity, while the highest malodor release was observed under 45â, with OU and TVOC concentration was 643.91 ± 2.49 and 7767.33 ± 33.50 mg/m3, respectively. Microbes with deodorization ability were screened and mixed into an agent, which composited of Bacillus amyloliquefaciens, Lactobacillus plantarum, Enterococcus faecalis and Pichia fermentans. The addition of microbial deodorant could significantly suppress the release of malodor gas during a 20-day trial, and the removal efficiency of NH3, H2S, TVOC and OU was 81.50 %, 38.31 %, 64.38 %, and 76.86 %, respectively. The analysis of microbial community structure showed that temperature was the main environmental factor driving the microbial variations in latrine feces, while Firmicutes, Actinobacteria, Proteobacteria and Bacteroidetes were the main bacteria phyla involved in the formation and emission of malodorous gases. However, after adding the deodorant, the abundance of Bacteroidetes, Proteobacteria and Actinobacteria were decreased, while the abundance of Firmicutes was increased. Furthermore, P. fermentans successfully colonized in fecal substrates and became the dominant fungus after deodorization. These results expanded the understanding of the odor release from latrine feces, and the composited microbial deodorant provided a valuable basis to the management of odor pollution.
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Desodorantes , Sulfuro de Hidrógeno , Gases , Odorantes , Cuartos de Baño , ChinaRESUMEN
A pilot-scale biological trickling filter (BTF) reactor (13.5 L) packed with different fillers (Pine bark, Cinder, Straw, and MBBR (mobile bed biofilm reactor) filler was employed to evaluate their removal performance of H2S and NH3 after heterotrophic bacterium addition, and some parameters, including different packing heights, empty bed residence time (EBRT), inlet titers, loading ratios, and restart trial, were investigated in this study. According to the experimental results, BTF filled with pine bark exhibited better removal efficiency than other reactors under a variety of conditions. The removal efficiency of H2S and NH3 reached to as high as 81.31 % and 91.72 %, respectively, with the loading range of 3.29-67.70 g/m3·h. Moreover, due to the addition of heterotrophic bacterium, the removal efficiency was enhanced and capable to eliminate majority of H2S and NH3 even though the packing height was reduced to 400 mm. After 15 days of idle, the BTF reactor was able to resume rapidly and execute deodorization with high efficiency. The degradation mechanism was further explored by a thorough examination of microbial species which degraded contaminants, as well as by functional prediction and correlation analyses. In a word, these results laid a foundation for the application of heterotrophic microorganisms in BTF, which could improve the removal efficiency of biological deodorization.
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Sulfuro de Hidrógeno , Filtración/métodos , Biopelículas , Reactores Biológicos , Bacterias/metabolismo , Biodegradación AmbientalRESUMEN
A heterotrophic nitrifying aerobic denitrifying (HN-AD) strain HY-1 with excellent capacity, identified as Paracoccus denitrificans, was isolated from activated sludge. HY-1 was capable of removing NH4+, NO2-, and NO3- with the corresponding rate of 17.33 mg-N L-1 h-1, 21.83 mg-N L-1 h-1, and 32.37 mg-N L-1 h-1, as well as the mixture of multiple nitrogen sources. Meanwhile, HY-1 could execute denitrification function under anaerobic conditions with a rate of 14.56 mg-N L-1 h-1. HY-1 required less energy investment, which exhibited average denitrification rate of 5.19 mg-N L-1 h-1 at carbon-nitrogen ratio was 1. After nitrification-denitrification metabolic pathway analysis, HY-1 was applied in a biological trickling filter reactor for compost deodorization. The results showed that adding of HY-1 greatly reduced the ionic concentration of NH4+ and NO3- in the circulating liquid without impairing the deodorization effect (NH3 removal rateï¼98.07%). These findings extend the field of application of HN-AD and provide new insights for biological deodorization.
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Desnitrificación , Nitrificación , Aerobiosis , Bacterias/metabolismo , Carbono , Procesos Heterotróficos , Nitritos/metabolismo , Nitrógeno/metabolismo , Dióxido de Nitrógeno , Aguas del Alcantarillado/microbiologíaRESUMEN
OBJECTIVES: To develop a novel ultrasound (US) plane to diagnose palatine tonsillar hypertrophy objectively in children. METHODS: Tonsillar ultrasonography of children (age 2-14 years) who had a clinical diagnosis of tonsillar hypertrophy or not were analyzed retrospectively. Clinical data (including gender, age, body mass index (BMI)), and volume (V) of tonsils measured by the US, were recorded. Furthermore, we found a new US plane to diagnose tonsillar hypertrophy and named it the submental oblique cross-section. In this plane, diameters of the left tonsil, right tonsil, and central oropharynx were designated as T1, T2, and O. Then, we calculated the ratio by the formula (T1 + T2)/O. RESULTS: A total of 172 cases (85 hypertrophy and 87 non-hypertrophy) were included in this study. There were no significant differences in gender (P = .844), age (P = .666), and BMI (P = .089) between the groups. In the non-hypertrophy group, the V of both sides had a positive linear correlation with age or BMI. In contrast, there was no linear correlation between ratio and age or BMI. The area under the curve (AUC) of ratio and V was 0.970 (95%CI: 0.947-0.993) and 0.835 (95%CI: 0.778-0.893) by receiver operating characteristic (ROC) analysis, respectively. The optimal cutoff value of ratio for diagnosis of tonsillar hypertrophy was 2.293 (sensitivity = 88.2%, specificity = 95.4%). CONCLUSIONS: We established a new US section to evaluate tonsillar hypertrophy. This approach could be easily acquired and provide a reference value to guide clinical practice.
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Tonsila Palatina , Niño , Humanos , Preescolar , Adolescente , Tonsila Palatina/diagnóstico por imagen , Proyectos Piloto , Estudios Retrospectivos , Hipertrofia/diagnóstico por imagen , UltrasonografíaRESUMEN
Cyanobacterial blooms impose a substantial risk for submerged macrophytes in aquatic environments. This study investigated the cellular and transcriptomic responses of Vallisneria natans to microcystin-LR (MCLR) exposure, as well as abscisic acid (ABA) and strigolactone (SL), which are the major compounds in signaling networks that regulate plant defense. The results revealed that MCLR significantly (p <0.05) decreased the photosynthetic pigments and significantly (p < 0.05) increased the contents of the ABA and SL stress-related phytohormones under MCLR stress. Related genes involved in the photosynthetic pathways were down-regulated, including psbO, psbP, psbQ and psbR. In the SL biosynthetic pathway of roots under MCLR stress, related genes, such as D27 and CCD7, were down-regulated, while the CCD8 and MAX1 genes were up-regulated. In the ABA synthetic pathway, the genes LUT5, ZEP, NCED, ABA2 and AAO3 were up-regulated. Furthermore, a reduction in the content of SL enriched ABA after 3 days under MCLR stress. The potential molecular mechanism of the interactions between SL and ABA were confirmed with the relative up- and down-regulated genes in the pathway, and ABA could play a major role in plant physiology under MCLR stress. This study provides valuable information to understand the stress-related mechanisms of response of submerged macrophytes to cyanobacterial blooms.
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Reguladores del Crecimiento de las Plantas , Contaminantes Químicos del Agua , Toxinas Marinas , Microcistinas/metabolismo , Microcistinas/toxicidad , Reguladores del Crecimiento de las Plantas/metabolismo , Transcriptoma , Contaminantes Químicos del Agua/toxicidadRESUMEN
In this work, the ammonium-tolerant duckweed Landoltia punctata 0202 was used to study the effect of ammonium stress on carbon and nitrogen metabolism and elucidate the detoxification mechanism. The growth status, protein and starch content, and activity of nitrogen assimilation enzymes were determined, and the transcriptional levels of genes involved in ion transport and carbon and nitrogen metabolism were investigated. Under high ammonium stress, the duckweed growth was inhibited, especially when ammonium was the sole nitrogen source. Ammonium might mainly enter cells via low-affinity transporters. The stimulation of potassium transport genes suggested sufficient potassium acquisition, precluding cation deficiency. In addition, the up-regulation of ammonium assimilation and transamination indicated that excess ammonium could be incorporated into organic nitrogen. Furthermore, the starch content increased from 3.97% to 16.43% and 26.02% in the mixed-nitrogen and ammonium-nitrogen groups, respectively. And the up-regulated starch synthesis, degradation, and glycolysis processes indicated that the accumulated starch could provide sufficient carbon skeletons for excess ammonium assimilation. The findings of this study illustrated that the coordination of carbon and nitrogen metabolism played a vital role in the ammonium detoxification mechanism of duckweeds.
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Compuestos de Amonio , Araceae , Araceae/genética , Carbono , Nitrógeno , AlmidónRESUMEN
Carriers strengthened duckweed treatment system (CDW), duckweed treatment system (DW) and water hyacinth treatment system (WH) were developed to treat rural wastewater in Dianchi Lake basin. Results showed that adding microbial carrier did not affect the growth and biomass components of duckweed. The following features were discovered in the CDW system. First, the NO3--N and TN removal efficiencies were the highest among three systems, reaching 80.02% and 56.42%, respectively. Secondly, Illumina sequencing revealed the highest microbial diversity. Thirdly, a distinct succession of microbial community was observed. Rhodobacter, Bacteria vadinCA02, C39 and Flavobacterium dominated in the start-up stage, and contributed to biofilm formation and pollutants degradation. Acinetobacter, Planctomyces and Methylibium significantly increased in the stable stage, and contributed to nitrogen removal. Finally, highly abundant plant growth-promoting bacteria were found. Comprehensive analysis indicated that the functional bacteria community was closely related to the pollutant removals, plant growth and system operating status.
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Araceae/metabolismo , Lagos/microbiología , Microbiota , Aguas Residuales/microbiología , Biomasa , Nitrógeno/metabolismoRESUMEN
The polyculture of different duckweed species is likely to integrate their advantages in removing pollutants and starch accumulation. Here, pilot-scale comparisons of three duckweed species (Spirodela polyrhiza K1, Lemna minor K2 and Landoltia punctata K3) in monoculture and polyculture were investigated. Results showed that the TN (total nitrogen) and TP (total phosphorus) in wastewater decreased from 6.0 and 0.56 mg L-1 to below 0.5 and 0.1 mg L-1, respectively. Namely, the water quality improved to Grade II under the Chinese standard. The highest TN and TP removal efficiencies were found to be 99.1% and 90.8% in the polyculture. Besides, the starch content of S. polyrhiza K1, L. minor K2, L. punctata K3 and the polyculture reached 24.8%, 32.3%, 39.3% and 36.3%, respectively. Accordingly, their average starch accumulation rates were 1.65, 2.15, 3.11 and 2.72 g m-2 d-1, respectively. Our results suggested that L. punctata K3 was a promising energy feedstock due to it having the highest starch production. The advantages of different duckweed species were investigated. In the polyculture, the pollutants were efficiently removed from wastewater, with a high starch accumulation. This study supplies a new insight into the application of duckweed in eutrophic water advanced treatment coupled with starch production.
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The fungal community and the population of 16S rRNA, 18S rRNA and cellulose-degrading genes during the 30-day composting process of Chinese medicinal herbal residues were investigated using Illumina MiSeq and quantitative real-time PCR. An obvious succession of fungal communities occurred during the composting process. Unidentified fungi predominated in the raw materials. As composting progressed, Ascomycota became the most dominant phylum, with Aspergillus being the most dominant genus, and Aspergillus fumigatus making up 99.65% of that genus. Because of the inoculation of cellulolytic fungi in the mature stage, the cellulose degradation rate in inoculation groups was faster and the relative abundances of Aspergillus and the glycoside hydrolase family 7 genes were significantly higher than those in the control groups. These indicated that the fungal inoculants facilitated the degradation of cellulose, increased cellulolytic fungi and optimized the community structure.
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Celulosa , ARN Ribosómico 16S , Microbiología del Suelo , Suelo , Hongos , Reacción en Cadena en Tiempo Real de la PolimerasaRESUMEN
We report on a systematic study of the absorption and emission spectral properties of (Yb(0.1)Y(0.9))(3)(Sc(1.5)Ga(0.5))Ga(3)O(12) (Yb:YSGG) crystals. The broad fluorescence spectral lines indicate great potential of Yb:YSGG for tunable and ultrafast laser applications. Efficient continuous-wave (cw) laser oscillation was also demonstrated at room temperature (RT), generating an output power of 6.11 W with an optical-to-optical efficiency of 64.2%, and a slope efficiency of 80.1% with respect to absorbed pump power. The laser emission spectrum shifts to shorter wavelengths as the transmission of the output coupler varies from 3% to 20%, a result that can be explained based on the effective gain cross-sections of Yb:YSGG.
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Cristalización , Rayos Láser , Iterbio/química , Iterbio/efectos de la radiación , Luz , Ensayo de Materiales , Dispersión de RadiaciónRESUMEN
A compact diode-pumped high-pulse-energy Yb:GdCa(4)O(BO(3))(3) laser passively Q-switched with a Cr(4+):YAG saturable absorber is demonstrated at room temperature. An output power of 1.05 W is generated at a pulse repetition rate of 2.5 kHz when the pump power absorbed is 7.7 W, with a slope efficiency determined to be 40%. The laser pulse generated is 10.0 ns in duration, with pulse energy as high as 420 µJ and peak power amounting to 42 kW.
RESUMEN
The passive Q-switching laser performance of Yb:YCa(4)O(BO(3))(3) is studied with crystals cut along the principal optical axes. Using a Cr(4+):YAG saturable absorber with initial transmission of 93.7% and an output coupler of transmission of 40%, efficient Q-switched laser operation is achieved with a X-cut crystal, generating an output power of 2.14 W at a pulse repetition rate of 4.5 kHz. The resulting laser pulse is 9.3 ns in duration, with the energy being as high as 476 µJ and the peak power amounting to 51.2 kW. The results demonstrated in this work reveal the great potential of this crystal in developing high-energy compact pulsed lasers.
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Rayos Láser , Transferencia de Energía , Diseño de Equipo , Análisis de Falla de Equipo , Estudios de FactibilidadRESUMEN
We demonstrate, for the first time, passively Q-switched laser operation of Yb:Y(3)Ga(5)O(12) garnet crystal. An output power of 4.53 W at 1031 nm was generated at a pulse repetition rate of 55.6 kHz, with a Cr(4+):YAG crystal acting as saturable absorber whose initial transmission was 97.5%, the corresponding pulse energy, duration and peak power were respectively 81.5 µJ, 28.5 ns and 2.86 kW. Laser pulses at a lower repetition rate of 18.2 kHz were also achieved at 1025 nm while the initial transmission of the Cr(4+):YAG crystal was 85.0%, with an output power measured to be 2.56 W, the resulting pulse energy, duration, and peak power being 140.8 µJ, 5.9 ns, and 23.9 kW, respectively.
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Rayos Láser , Diseño de Equipo , Análisis de Falla de EquipoRESUMEN
We report on a significant improvement in cw laser performance of the disordered Yb:CNGG crystal. Very efficient cw laser operation is demonstrated at room temperature with a 3.5 mm thick crystal end pumped by a diode laser, generating an output power of 5.15 W with an optical-to-optical efficiency of 46%, whereas the slope efficiency amounts to 80%.
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Efficient laser operation is demonstrated at room temperature with a new Yb:Lu3Ga5O12 garnet crystal. A continuous-wave output power of 5.36 W is generated at a center oscillation wavelength of 1041 nm, with an optical-to-optical efficiency of 51% and the slope efficiency of 63%. In passively Q-switched operation, the maximum average output power reaches 4.0 W (center wavelength of 1034 nm) at a repetition rate of 71 kHz, with optical-to-optical and slope efficiencies measured to be 40% and 50%, respectively. Laser pulses of 26 ns duration are generated with a pulse energy of 91 µJ and peak power of 3.5 kW.