Treatment of nitrogen and phosphorus from sewage tailwater in paddy rice wetlands: concept and environmental benefits.

Domestic sewage tailwater (DSTW) reuse for crop irrigation is considered a promising practice to reduce water demand, mitigate water pollution, and substitute chemical fertilization. The level of the above environmental benefits of this water reuse strategy, especially when applied to paddy wetlands, remains unclear. In this study, soil column experiments were conducted to investigate the nitrogen and phosphorus fate in paddy wetlands subjected to different tailwater irrigation and drainage strategies, specifically, (i) TW1 and TW2 for regular or enhanced irrigation-drainage without N fertilization, (ii) TW3 and TW4 for regular irrigation with base or tillering N fertilizer, (iii) conventional fertilization N210, and (iv) no-fertilization controls N0. The results showed that the total nitrogen (TN), nitrate (NO3-), and total phosphorus (TP) removal rates from the paddies irrigated by DSTW ranged between 51.92 and 59.34%, 68.1 and 83.42%, and 85.69 and 86.98% respectively. Ammonia emissions from the DSTW-irrigated treatments were reduced by 14.6~47.2% compared to those paddies subjected to conventional fertilization (N210), similarly for TN emissions, with the exception of the TW2 treatment. Overall, it is established that the paddy wetland could effectively remove residual N and P from surface water runoffs, while the partial substitution of chemical fertilization by DSTW could be confirmed. The outcome of this study demonstrates that DSTW irrigation is a promising strategy for sustainable rice production with a minimized environmental impact.

Efficient photocatalysis of tetracycline hydrochloride (TC-HCl) from pharmaceutical wastewater using AgCl/ZnO/g-C3N4 composite under visible light: Process and mechanisms.

AgCl/ZnO/g-C3N4, a visible light activated ternary composite catalyst, was prepared by combining calcination, hydrothermal reaction and in-situ deposition processes to treat/photocatalyse tetracycline hydrochloride (TC-HCl) from pharmaceutical wastewater under visible light. The morphological, structural, electrical, and optical features of the novel photocatalyst were characterized using scanning electron microscopy (SEM), UV-visible light absorption spectrum (UV-Vis DRS), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and transient photocurrent techniques. All analyses confirmed that the formation of heterojunctions between AgCl/ZnO and g-C3N4 significantly increase electron-hole transfer and separation compared to pure ZnO and g-C3N4. Thus, AgCl/ZnO/g-C3N4 could exhibit superior photocatalytic activity during TC-HCl assays (over 90% removal) under visible light irradiation. The composite could maintain its photocatalytic stability even after four consecutive reaction cycles. Hydrogen peroxide (H2O2) and superoxide radical (·O2) contributed more than holes (h+) and hydroxyl radicals (·OH) to the degradation process as showed by trapping experiments. Liquid chromatograph-mass spectrometer (LC-MS) was used for the representation of the TC-HCl potential degradation pathway. The applicability and the treatment potential of AgCl/ZnO/g-C3N4 against actual pharmaceutical wastewater showed that the composite can achieve removal efficiencies of 81.7%, 71.4% and 69.0% for TC-HCl, chemical oxygen demand (COD) and total organic carbon (TOC) respectively. AgCl/ZnO/g-C3N4 can be a prospective key photocatalyst in the field of degradation of persistent, hardly-degradable pollutants, from industrial wastewater and not only.

Temperature and immigration effects on quorum sensing in the biofilms of anaerobic membrane bioreactors.

Quorum sensing (QS), a microbial communication mechanism modulated by acyl homoserine lactone (AHL) molecules impacts biofilm formation in bioreactors. This study investigated the effects of temperature and immigration on AHL levels and biofouling in anaerobic membrane bioreactors. The hypothesis was that the immigrant microbial community would increase the AHL-mediated QS, thus stimulating biofouling and that low temperatures would exacerbate this. We observed that presence of immigrants, especially when exposed to low temperatures indeed increased AHL concentrations and fouling in the biofilms on the membranes. At low temperature, the concentrations of the main AHLs observed, N-dodecanoyl-L-homoserine lactone and N-decanoyl-L-homoserine lactone, were significantly higher in the biofilms than in the sludge and correlated significantly with the abundance of immigrant bacteria. Apparently low temperature, immigration and denser community structure in the biofilm stressed the communities, triggering AHL production and excretion. These insights into the social behaviour of reactor communities responding to low temperature and influx of immigrants have implications for biofouling control in bioreactors.

Low-Temperature Pretreatment of Organic Feedstocks with Selected Mineral Wastes Sustains Anaerobic Digestion Stability through Trace Metal Release.

A low-cost approach for enhancing mesophilic (37 °C) anaerobic digestion (AD) of organic waste using a low-temperature (37 °C) pretreatment with different mineral wastes (MW) was investigated. A higher and stable methane production rate, in comparison to MW-free controls, was achieved for 80 days at organic loading rates of 1-2 g VS/L·d, using a feed substrate pretreated with incinerator bottom ash (IBA). The boiler ash and cement-based waste pretreatments also produced high methane production rates but with some process instability. In contrast, an incinerator fly ash pretreatment showed a progressive decrease in methane production rates and poor process stability, leading to reactor failure after 40 days. To avoid process instability and/or reactor failure, two metrics had to be met: (a) a methanogenesis to fermentation ratio higher than 0.6 and (b) a cell-specific methanogenic activity to cell-specific fermentation activity ratio of >1000. The prevalence of Methanofastidiosum together with a mixed community of acetoclastic (Methanosaeta) and hydrogenotrophic (Methanobacterium) methanogens in the stable IBA treatment indicated the importance of Methanofastidiosum as a potential indicator of a healthy and stable reactor.

Improving the methane productivity of anaerobic digestion using aqueous extracts from municipal solid waste incinerator ash.

This study investigated the effects of mineral waste extracts (MWE) on laboratory-scale two-stage anaerobic digesters treating synthetic organic waste. MWE was prepared as aqueous extracts from different ash samples (incineration bottom ash (IBA), fly ash (FA) and boiler ash (BA) taken from a municipal solid waste incineration plant. At 20 days hydraulic retention time, all three MWE stimulated hydrogen production in their respective acidogenic reactor by around 35% (c.f. control acidogenic reactor), whilst no difference was seen in the methane productivity of the linked methanogenic reactors (average 527 ± 45 mL CH4/g VS, including control methanogenic reactor). Following a step reduction in hydraulic retention time from 20 to 10 days and a doubling of the organic loading rate from 2.5 g to 5 g VS/L. d, no significant change was seen in hydrogen production (p > 0.05) in the acidogenic reactor amended with MWE from IBA and BA, or the control acidogenic reactor. However, the acidogenic reactor receiving MWE from FA had 45% lower hydrogen productivity. The step change in hydraulic retention time and organic loading rates led to the failure of most methanogenic reactors (≤100 mL CH4/g VS), however, the one receiving feed containing MWE from IBA showed stable performance without signs of failure, and had higher volumetric methane productivity, albeit at lower methane yields (370 ± 20 mL CH4/g VS). 16S rRNA analysis using the Illumina sequencing platform revealed acidogenesis by Lactobacillaceae in the acidogenic reactor and syntrophic acetate oxidation by Synergistaceae linked to enrichment of the candidatus genus Methanofastidiosum, in the stable methanogenic reactor receiving MWE from IBA.

Tick-borne Encephalitis: Stroke-like Presentation.

Tick-borne encephalitis, caused by the tick-borne virus (TBEV), is endemic in central, eastern, and northern Europe eastwards through Russian Siberia and China. For the year 2009, the highest incidence in Scandinavian countries was in Sweden. The clinical symptoms have a wide spectrum. We report a unique case of clinical symptoms and radiological findings compatible with a stroke-like inflammatory lesion in the thalamus, suggesting microangiopathy from TBEV. Our case shows that TBEV could be a possible cause of stroke-like lesions.

Urban green space area mitigates the accumulation of heavy metals in urban soils.

Despite that the heavy metals in urban soils pose a threat to public health, the critical factors that influence their concentrations in urban soils are not well understood. In this study, we conducted a survey of surface soil samples from urban green spaces in Shanghai, to analyze the concentrations of the key heavy metals. The results showed that Zn was the most abundant metal with an average concentration of 122.99 mg kg-1, followed by Pb (32.72 mg kg-1) and Cd (0.23 mg kg-1). All concentrations were found to be below the risk screening values defined by the National Environmental Quality Standards for soils of development land in China (GB36600-2018), indicating no current risk in Shanghai. However, there was a clear accumulation of heavy metals, as the mean concentrations were significantly higher than the background values. Furthermore, we explored the relationships between key heavy metals with population density, GDP and green space area. Both Spearman correlation and Random Forest analysis indicated that per capita green space area (pGSA) and population density were the most crucial factors influencing the status of heavy metals in urban soils, unlike edaphic factors e.g. SOM content in farmland soils. Specifically, there was a significantly positive linear correlation between heavy metal concentrations and population density, with correlation coefficients ranging from 0.3 to 0.4. However, the correlation with pGSA was found to be non-linear. The nonlinear regression analysis revealed threshold values between heavy metals concentrations and pGSA (e.g Zn 22.22 m2, Pb 24.92 m2, and Cd 25.92 m2), with a sharp reduction in heavy metal concentrations below the threshold and a slow reduction above the threshold. It suggests that an increase in per capita green space area can mitigate the accumulation of heavy metals caused by growing population density, but the effect is limited after the threshold. Our findings not only provide insights into the distribution patterns of heavy metals in the urban soils at the local scale, but also contribute to the urban greening at the global scale and offer guidance for city planning in the face of increasing population densities over the coming decades.

The impact of Ag nanoparticles on methane emission in two typical paddy soils.

Numerous applications of Ag nanoparticles (AgNPs) have increased the likelihood of their release and accumulation in agroecosystem. Thus far, few studies have evaluated the impacts of AgNPs to soil methane emissions and the microbial dynamics. In this study, microcosmic experiments were conducted to investigate the responses of methanogenic processes from two paddy soils (Cambisols and Ultisols) subjected to four AgNPs doses (0.1, 1, 10 and 50 mg/kg). The results showed that 0.1 and 1 mg/kg AgNPs had no significant effects on CH4 emissions, but 50 mg/kg AgNPs increased soil CH4 emissions in both paddy soils. The aggravation effect of AgNPs on CH4 emissions was more apparent in Ultisols compared to Cambisols paddy soils. Real-time PCR suggested that 50 mg/kg AgNPs significantly increased the ratio of methanogenic to bacterial gene for both paddy soils. Amplicon sequencing indicated that methanogenic community was clustered into a separate group after 50 mg/kg AgNPs exposure. Structural equation model illustrated that Methanosarcinales was both significantly responded to AgNPs in Cambisols and Ultisols soils; however, Methanocellales significantly responded to AgNPs only in Cambisols soils. Subsequently, uncontrolled use of AgNPs may account as an environmental risk due to the potentially increased soil CH4 emissions in paddy ecosystems.

Changes in soil stoichiometry, soil organic carbon mineralization and bacterial community assembly processes across soil profiles.

Soil organic carbon (SOC) mineralization is essential to biogeochemical recycling in terrestrial ecosystem. However, the microbial mechanisms underlying the nutrient-induced SOC mineralization remain uncertain. Here, we investigated how SOC mineralization was linked to microbial assembly processes as well as soil nutrient availability and stoichiometric ratio in a paddy rice ecosystem at four soil profile levels. Our results showed a sharp decrease in SOC mineralization from topsoil (112.61-146.34 mg CO2 kg-1 day-1) to subsoil (33.51-61.41 mg CO2 kg-1 day-1). High-throughput sequencing showed that both abundance and diversity of specialist microorganisms (Chao1: 1244.30-1341.35) significantly increased along the soil profile, while the generalist microorganisms (Chao1: 427.67-616.15; Shannon: 7.46-7.97) showed the opposite trend. Correspondingly, the proportion of deterministic processes that regulate specialist (9.64-21.59 %) and generalist microorganisms (21.17-53.53 %) increased and decreased from topsoil to subsoil, respectively. Linear regression modeling and partial least squares path modeling indicated that SOC mineralization was primarily controlled by the assembly processes of specialist microorganisms, which was significantly mediated by available soil C:N:P stoichiometry. This study highlighted the importance of soil stoichiometry-mediated bacterial community assembly processes in regulating SOC mineralization. Our results have an important implication for the integration of bacterial community assembly processes into the prediction of SOC dynamics.

Long-Term Manure Amendment Sustains Black Soil Biodiversity by Mitigating Acidification Induced by Chemical N Fertilization.

The long-term use of chemical N fertilization may have a negative impact upon soil fertility and quality. On the contrary, organic fertilization is considered a sustainable development agricultural strategy. However, the remediation effect of organic fertilization on agroecosystems remains unclear. This study was conducted in a long-term (1979−2020) field experiment to investigate the influence of organic and chemical fertilizers on the soil microbiome assembly processes. The experiment consisted of six treatments: chemical N fertilization (N), double N fertilization (N2), organic fertilization (M), organic and N fertilization (MN), double organic and N fertilization (M2N2), and unfertilized control. The chemical N fertilization (N and N2) treatments significantly decreased soil microbial diversity, as well as soil pH, compared to the Control treatments (p < 0.05). MN and M2N2 treatments increased microbial diversity compared to that of N and N2 treatments. The combination of organic and chemical N fertilizer recovered the decreased microbial diversity to the level of the Control and M treatments, but the application of double organic fertilizer (M2N2) still showed a significantly lower microbial diversity than that of the Control and M treatments. From the results of the microbial community assembly processes, it was found that environmental filtering was induced by N fertilization, while organic fertilization developed a stochastic process and mitigated the role of environmental filtering in the community assembly process. An ecological network analysis showed that the decrease in Acidobacteria in organic fertilization treatments played a key role in mitigating the soil acidification induced by 40-year chemical N fertilization. It indicated that organic fertilizer could mitigate the decrease in soil fertility induced by chemical N fertilization. Higher environmental filtering effects in M2N2 than those in MN treatments suggested that the mitigation effect of organic fertilizer was weakened when double chemical N fertilization was applied in black soils. These results are helpful for a unified understanding of the ecological processes for microbial communities in the development of sustainable agriculture.

Phosphate removal from actual wastewater via La(OH)3-C3N4 adsorption: Performance, mechanisms and applicability.

In this study, La(OH)3 nanoparticles were immobilized on C3N4 to effectively restrict their aggregation and subsequently enhance the La utilization efficiency to promote phosphate adsorption. The prepared La(OH)3-C3N4 nanocomposite was characterized by SEM, XRD, FTIR, XPS, BET and Zeta potential analysis. Batch and continuously-fed (fixed-bed column) experiments to assess the adsorption performance of La(OH)3-C3N4 showed that the composite exhibits superior utilization efficiency, resulting to relatively quick adsorption with a short equilibrium time of 30 min. The theoretical maximum P adsorption capacity reached the 148.35 mg·g-1, efficiency that remained unaffected by the anions and HA present. The adsorption mechanism showed stability in a wide pH range (4.0-11.0) and is considered effective even after extensive use (five-cycles). The dynamics of the adsorption capacity and the half-penetration time values were estimated by 'Thomas' and 'Yoon-Nelson' models showed that are better represented from the experimental values obtained from the fixed-bed column trial. The adsorption mechanisms were attributed to surface precipitation, electrostatic attraction, and inner-sphere complexation via ligand exchange. Furthermore, La(OH)3-C3N4 demonstrated high efficiency in scavenging phosphate from both diluted and concentrated wastewater (natural pond and swine wastewater respectively). The above confirm that La(OH)3-C3N4 is a promising composite material for phosphate management in aqueous environments.

Organic and Inorganic Amendments Shape Bacterial Indicator Communities That Can, In Turn, Promote Rice Yield.

The dynamic patterns of the belowground microbial communities and their corresponding metabolic functions, when exposed to various environmental disturbances, are important for the understanding and development of sustainable agricultural systems. In this study, a two-year field experiment with soils subjected to: chemical fertilization (F), mushroom residues (MR), combined application of chemical fertilizers and mushroom residues (MRF), and no-fertilization (CK) was conducted to evaluate the effect of fertilization on the soil bacterial taxonomic and functional compositions as well as on the rice yield. The highest rice yield was obtained under MRF. Soil microbial properties (microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), urease, invertase, acid phosphatase, and soil dehydrogenase activities) reflected the rice yield better than soil chemical characteristics (soil organic matter (SOM), total N (TN), total K (TK), available P (AP), available K (AK), and pH). Although the dominant bacterial phyla were not significantly different among fertilizations, 10 bacterial indicator taxa that mainly belonged to Actinobacteria (Nocardioides, Marmoricola, Tetrasphaera, and unclassified Intrasporangiaceae) with functions of xenobiotic biodegradation and metabolism and amino acid and nucleotide metabolism were found to strongly respond to MRF. Random Forest (RF) modeling further revealed that these 10 bacterial indicator taxa act as drivers for soil dehydrogenase, acid phosphatase, pH, TK, and C/N cycling, which directly and/or indirectly determine the rice yield. Our study demonstrated the explicit links between bacterial indicator communities, community function, soil nutrient cycling, and crop yield under organic and inorganic amendments, and highlighted the advantages of the combined chemical and organic fertilization in agroecosystems.

Tea plant-legume intercropping simultaneously improves soil fertility and tea quality by changing bacillus species composition.

Tea plant is an economically important crop in China, but long-term monoculture and substantial chemical nitrogen fertilizer input cause soil acidification, which in turn affects the nutrient supply and tea quality. Intercropping has drawn more attention in tea gardens because this pattern is expected to improve soil fertility and tea quality and change the soil microbial community composition. However, the roles of some key microorganisms in rhizosphere soils have not been well characterized. Hereby, a "soybean in summer and smooth vetch in winter" mode was selected to investigate the effects of intercropped legumes in a tea garden on soil fertility, tea quality, and the potential changes in beneficial bacteria such as Bacillus. Our data showed that when soybeans were turned into soil, intercropping system exhibited higher soil organic matter (SOM), total nitrogen (TN), tea quality indices and the expression of Camellia sinensis glutamine synthetase gene (CsGS). Notably, intercropping significantly affected the bacterial communities and decreased the relative abundance of Bacillus but increased its absolute abundance. Bacillus amyloliquefaciens BM1 was isolated from intercropped soil and showed outstanding plant growth-promoting (PGP) properties when coinoculated with rhizobia. In winter, intercropping with smooth vetch had a beneficial effect on soil properties and tea quality. Comparably, coinoculation with strain BM1 and Rhizobium leguminosarum Vic5 on smooth vetch (Vicia villosa) showed huge improvements in SOM, TN and quality of tea leaves, accompanied by the highest level of amino acids and lowest levels of polyphenol and caffeine (p < 0.05). According to these results, our findings demonstrate that intercropping with some legumes in the tea garden is a strategy that increases SOM, TN and tea quality, and some PGP Bacillus species are optional to obtain an amplification effect.

Microbial-Induced Carbonate Precipitation Improves Physical and Structural Properties of Nanjing Ancient City Walls.

The preservation and restoration of heritage sites have always been of key focus in the field of cultural relics. Current restoration methods mainly involve physical or chemical techniques, which are in many cases intrusive, destructive, and irreversible. Hereby, we introduce a novel biological strategy (microbial-induced carbonate precipitation (MICP)) to repair natural and simulated surface cracks on six hundred years' old wall bricks (part of the Nanjing City Min Dynasty ancient wall, China). X-ray micro computed tomography (X-ray micro-CT) was employed to non-destructively visualize the internal structure of the MICP-treated brick cubes. The results showed that MICP can effectively repair both natural and simulated cracks present on the brick's surface. The compressive strength of the MICP-treated brick cubes was significantly higher than that of the untreated control cubes (33.56 ± 9.07 vs. 19.00 ± 1.98 kN, respectively). MICP significantly increased the softening coefficient and decreased the water absorption rate (p < 0.05), indicating that the water resistance of the wall bricks can be improved after treatment. The 3D images from X-ray micro-CT, a method that could non-destructively assess the internals of such cultural structures, showed that MICP can effectively repair ancient relics, promoting durability and limiting degradation without affecting the structure. X-ray diffraction analyses showed that MICP generates the same calcite form as that of original bricks, indicating that MICP filler is compatible with the ancient city wall brick. These findings are in line with the concept of contemporary heritage preservation.

Assessing the ecological risk of pesticides should not ignore the impact of their transformation byproducts - The case of chlorantraniliprole.

Risk assessments for pesticides typically focus on the compound itself ignoring the impact of its transformation byproducts. Challenges in isolating such byproducts (i.e. after application of pesticide in soil) often lead to underestimation of the real risk from such substances. The toxicological properties of these byproducts may differ from those of the parent pesticides; hence, special attention is required for these new emerging contaminants. In this study, two transformation byproducts of chlorantraniliprole were isolated from soil and identified, using nuclear magnetic resonance and high resolution mass spectrometry, as products of dechlorination (Z1) and bromination (Z2). Kinetic experiments revealed both byproducts degrade faster than chlorantraniliprole in soil (half-lives 38 & 43 d vs. 58 d). The ecological risk evaluation of chlorantraniliprole and its byproducts on soil bacterial community showed that they were all potentially harmful but they imposed different impacts on both alpha and beta diversities and co-occurrence networks of the bacterial community. Z2 had the biggest potential impact on soil bacteria and accounted as a high potential risk. By comparing their impacts on soil bacterial community, we confirm that ecological risk assessment necessitates the understanding of the environmental impacts of a substance as well as of its transformation byproducts.

Nutrient loss by runoff from rice-wheat rotation during the wheat season is dictated by rainfall duration.

Clarifying the properties/features of nutrient loss from farmland surface runoff is essential for the mitigation of nutrient losses. Plough pan formation underneath topsoil is a common feature of long-term paddy soils that significantly affects water movement and nutrient runoff loss, especially during the upland season of paddy-upland rotation. To characterize the nutrients that are lost from wheat fields of paddy-wheat rotation with runoff, a field experiment was conducted in a wheat field using a simulated rainfall system from November 2019 to May 2020 in Nanjing, China. The aim of this study was to investigate the temporal characteristics of nitrogen (N) and phosphorus (P) loss under different rainfall intensities (low, 30 mm h-1; middle, 60 mm h-1; high, 90 mm h-1). The results showed that the time interval from the beginning of rain to the occurrence of runoff (time to runoff, Tr) was negatively correlated with "rainfall intensity" (Ri) (P＜0.01) but unaffected by soil moisture. Different rainfall intensities had no effect on the runoff coefficient (the ratio of the runoff volume over the precipitation, 0.14-0.17). The N and P loss concentrations in the nutrient discharge followed a power-function relationship that decreased over time (P＜0.01), and the peak nutrient concentration appeared during the initial runoff period (0-5 min). The N and P loss rates were the highest during the middle-to-late discharge period (15-30 min) for all intensities. In terms of cumulative nutrient losses, the amounts of TN lost were similar for all rainfall intensities, while TP significantly increased with intensity. The results revealed that nitrate-nitrogen (NOX--N) and particulate phosphorus (PP) were the predominant forms of N and P losses. Overall, during the initial runoff period, nutrient concentration peaks, whereas the nutrient loss rate is the highest during the middle-late phase of the phenomenon.

Effect of fertilization on nitrogen losses through surface runoffs in Chinese farmlands: A meta-analysis.

Surface runoff is the main cause of farmland nitrogen (N) losses in plain areas, which adversely affect water quality. The impact of fertilization on N runoff loss often varies. A meta-analysis was performed using 245 observations from 31 studies in China, to estimate the response of N loss in both paddy and upland fields subjected to different fertilization strategies, and investigate the link between N runoffs, soil properties, as well as precipitation in the planting season. The results showed that compared to the control (without fertilization), N losses subjected to fertilization increased from 3.31 kg/ha to 10.03 kg/ha and from 3.00 kg/ha to 11.24 kg/ha in paddy and upland fields respectively. Importantly, paddy N loss was significantly correlated with fertilizer type and N application rate (predictors); in upland fields N application rate and seasonal precipitation were the main driving factors. For the N application rate, N loss increased with increase in rates for both paddies and upland fields. Moreover, the N loss from upland fields increased with the precipitation during planting season. Between the three fertilizers used in paddies, the increase in loss of CRF (controlled release fertilizer) or OF (organic fertilizer) was lower than that of CF (inorganic chemical fertilizer) with the lowest value in CRF. Subset analysis showed that the effect of CRF and OF in paddies was not affected by the predictors, revealing the steadily controlling property of CRF and OF in paddies. Also, all the predictors had an insignificant impact to N loss risk in paddies during the high application rate. Overall, the results confirm the importance of N dosage in N runoff loss from farmland. Fertilizer type is a key consideration for N loss control in paddies, while the seasonal precipitation should not be ignored in upland fields.

Mitigation of membrane biofouling in membrane bioreactor treating sewage by novel quorum quenching strain of Acinetobacter originating from a full-scale membrane bioreactor.

A novel quorum quenching (QQ) strain, Acinetobacter guillouiae ST01, was isolated from a full-scale membrane bioreactor (MBR) and characterized for its QQ activities. Batch reactor studies at lab-scale showed that A. guillouiae ST01 exhibited higher QQ activity against acyl homoserine lactones (AHLs) with an oxo group compared to those without an oxo group. The organism was then inoculated (10%) in an MBR (Q-MBR) treating sewage over 48 days and was found to reduce quorum sensing (QS) activity by reducing AHL concentrations in the sludge and the biofilm of the Q-MBR. The concentration of polysaccharides was reduced up to 30% in both the biofilm and sludge relative to the control, whereas protein concentrations were reduced by 40% and 47% in the sludge and biofilm, respectively. The Q-MBR fouling rates were halved. These results indicate that A. guillouiae ST01 is a promising strain for biofouling reduction in MBR treating real wastewater.

Humidity governs the wall-inhabiting fungal community composition in a 1600-year tomb of Emperor Yang.

Biodeterioration caused by filamentous fungi is often a threat to the architectural heritage (i.e. tombs and historic sites). To specifically understand the deterioration phenomena caused by microorganisms in tombs and how these are shaped due to various environmental factors, the fungal communities in the coffin chamber of the Chinese emperor Yang (BC 569-618) were investigated at different heights using denaturant gradient gel electrophoresis (DGGE) fingerprinting. The associated environmental conditions, such as humidity, temperature, height and illumination, were also assessed. The results showed that a great diversity of fungal species (Cordyceps, Fusarium, Harpochytrium, Emericellopsis, Volutella, Cladosporium, Stachybotrys, Trichoderma, Cochlonema and two unknown fungal species) was present in emperor Yang's coffin chamber. The predominant species were Stachybotrys, Fusarium, Trichoderma and Cochlonema. Redundancy analysis (RDA) indicated that humidity, temperature, height and illumination were the most significantly related factors shaping the fungal communities. Humidity showed the highest degree of variance description (19.2%) than all other environmental factors, followed by illumination (18.3%) and height (12.8%). Furthermore, fungal richness and diversity indices showed a positive correlation with humidity (p < 0.05). These results help in understanding the fungal community in tombs, promoting the mitigation of deterioration phenomena of such building heritage for the present and future.

Diversity of Acyl Homoserine Lactone Molecules in Anaerobic Membrane Bioreactors Treating Sewage at Psychrophilic Temperatures.

This study explores the types of acyl homoserine lactone (AHL) and their concentrations in different compartments of different conventional anaerobic bioreactors: (i) an upflow anaerobic membrane bioreactor (UAnMBR, biofilm/mixed liquor (sludge)); (ii) an anaerobic membrane bioreactor (AnMBR, biofilm/mixed liquor (sludge)); and (iii) an upflow sludge blanket (UASB, sludge only), all operating at 15 °C. Ten types of the AHL, namely C4-HSL, 3-oxo-C4-HSL, C6-HSL, 3-oxo-C6-HSL, C8-HSL, 3-oxo-C8-HSL, C10-HSL, 3-oxo-C10-HSL, C12-HSL, and 3-oxo-C12-HSL, which were investigated in this study, were found in UAnMBR and UASB, whilst only six of them (C4-HSL, 3-oxo-C4-HSL, C8-HSL, C10-HSL, 3-oxo-C10-HSL, and C12-HSL) were found in AnMBR. Concentrations of total AHL were generally higher in the biofilm than the sludge for both membrane bioreactors trialed. C10-HSL was the predominant AHL found in all reactors (biofilm and sludge) followed by C4-HSL and C8-HSL. Overall, the UAnMBR biofilm and sludge had 10-fold higher concentrations of AHL compared to the AnMBR. C10-HSL was only correlated with bacteria (p < 0.05), whilst other types of AHL were correlated with both bacteria and archaea. This study improves our understanding of AHL-mediated Quorum Sensing (QS) in the biofilms/sludge of UAnMBR and AnMBR, and provides new information that could contribute to the development of quorum quenching anti-fouling strategies in such systems.