Effect of bioaugmentation on gas production and microbial community during anaerobic digestion in a low-temperature fixed-bed reactor

Low temperature is one of the limiting factors for anaerobic digestion in cold regions. To improve the efficiency of anaerobic digestion for methane production in stationary reactors under low-temperature conditions, and to improve the structure of the microbial community for anaerobic digestion at low temperatures. We investigated the effects of different concentrations of exogenous Methanomicrobium (10, 20, 30%) and different volumes of carbon fiber carriers (0, 10, 20%) on gas production and microbial communities to improve the performance of low-temperature anaerobic digestion systems. The results show that the addition of 30% exogenous microorganisms and a 10% volume of carbon fiber carrier led to the highest daily (128.15 mL/g VS) and cumulative (576.62 mL/g VS) methane production. This treatment effectively reduced the concentrations of COD and organic acid, in addition to stabilizing the pH of the system. High-throughput sequencing analysis revealed that the dominant bacteria under these conditions were Acidobacteria and Firmicutes and the dominant archaea were Candidatus_Udaeobacter and Methanobacterium. While the abundance of microorganisms that metabolize organic acids was reduced, the functional abundance of hydrogenophilic methanogenic microorganisms was increased. Therefore, the synergistic effect of Methanomicrobium bioaugmentation with carbon fiber carriers can significantly improve the performance and efficiency of low-temperature anaerobic fermentation systems

Expression of Inflammatory Factors in Critically Ill Patients with Urosepticemia and the Imaging Analysis of the Severity of the Disease

Urine sepsis is a complex inflammatory response of the body to infection with a high fatality rate. It is one of the main causes of death in noncardiovascular intensive care units. Nevertheless, in daily clinical practice, early sepsis is often not detected. In this paper, discharged cases of urinary sepsis from the Department of Urology and Critical Care Medicine of a university hospital were collected as the observation group, and common urinary tract infection cases were selected as the control group. We sorted and summarized the discharged case information of the observation group and the control group. The results of the study showed that, after renal pelvis perfusion, the expression of HMGB1 protein and mRNA increased, and the expression of TLR4 increased; inhibiting HMGB1 can reduce the expression of inflammatory factors caused by perfusion and reduce the infiltration of neutrophils and macrophages caused by perfusion. In addition, r HMGB1 treatment can promote the expression of inflammatory factors caused by perfusion and aggravate the infiltration of neutrophils and macrophages caused by perfusion. We found that inhibition of HMGB1 can inhibit the expression of TLR4/My D88 signaling molecules and r HMGB1 treatment can enhance the expression of TLR4/My D88 signaling molecules

Changes of Coastal Wetland Ecosystems in the Yellow River Delta and Protection Countermeasures to Them

Coastal wetlands in the Yellow River Delta are typical new wetland ecosystems in warm temperate zone. In recent years, influenced by natural and human factors, these coastal wetlands in the Yellow River Delta have undergone changes of landscape fragmentation, vegetation degradation, pollution, species reduction, and harmful exotic species invasion. These changes have influenced sustainable and healthy development of marine economy of the Yellow River Delta. To protect natural ecological environment of the Yellow River Delta, the authors recommended that it should establish and improve policies, laws and regulations of wetland protection; carry out wetland resource investigation and assessment and monitoring; strengthen comprehensive protection and control of wetland; reduce wetland degradation and promote sustainable use of wetland

Degrading capability and activity of extracellular xylanase secreted by a composite microbial system XDC-2

The natural lignocellulose degrading capabilities of extracellular enzyme secreted by a composite microbial system XDC-2 were studied. Peptone cellulose solution (PCS) medium was beneficial to the degradation of lignocellulosic materials and ATCC 1053 medium promoted enzyme production of XDC-2. The exocellular xylanase activities of the crude enzymes were stable below 40°C. The crude enzyme has an effective capability of degrading natural lignocellulose, especially natural hemicellulose. The corn stalk core and rice straw lost 21.1 and 11.9% of its weight, respectively, after 48 h hydrolysis by the crude enzyme, and the weight loss of hemicellulose of corn stalk core and rice straw was 84.7 and 27.8%, respectively. Qualitative scanning electron microscopes (SEM) images indicated that after 48 h crude enzymes hydrolysis at 35°C, the material structure was modified. The production of the soluble carbohydrates was up to 2, 400 mg·L-1 for corn straw and 1, 300 mg·L-1 for rice straw. It would hold the potential of further development and application of XDC-2 with the ability to hydrolyze natural lignocelluloses and release soluble carbohydrates.Keywords: Composite microbial system, lignocellulose degradation, exocellular xylanase, hydrolysis abilit

Effects of biogas residue addition, as cultivation substrate, on ginseng growth

The effects of biogas residue as a substrate on ginseng growth and its feasibility for ginseng cultivation are unclear. The present study used biogas residue at different concentrations and maturity levels to cultivate ginseng. The biological characteristics of ginseng, soil physiochemical indices, and ginseng and soil microbial communities were investigated. The results showed that with increasing ginseng content and maturity, the total fresh weight, total length and saponin content significantly increased. The enzyme activities of soil, NO3--N, and available phosphorus also increased. The microbiome analysis revealed that with the addition of biogas residue, microorganisms related to plant growth promotion, such as Chloroflexi, Gemmatimonadota and Mortierellomycota, were more common in the plant or rhizosphere soil. The results based on the co-occurrence network showed that the structure of the bacterial community was more stable than that of the fungal community with increasing biogas residue content. Our results indicated that biogas residue could be used as a ginseng cultivation substrate and promote growth

Formation and In Situ Treatment of High Fluoride Concentrations in Shallow Groundwater of a Semi-Arid Region: Jiaolai Basin, China

Fluorine is an essential nutrient, and excessive or deficient fluoride contents in water can be harmful to human health. The shallow groundwater of the Jiaolai Basin, China has a high fluoride content. This study aimed to (1) investigate the processes responsible for the formation of shallow high-fluoride groundwater (SHFGW); (2) identify appropriate methods for in situ treatment of SHFGW. A field investigation into the formation of SHFGW was conducted, and the results of experiments using soils from high-fluoride areas were examined to investigate the leaching and migration of fluoride. The results showed that the formation of SHFGW in the Jiaolai Basin is due to long-term geological and evaporation processes in the region. Stratums around and inside the basin act as the source of fluoride whereas the terrain promotes groundwater convergence. The hydrodynamic and hydrochemical conditions resulting from slow groundwater flow along with high evaporation and low rainfall all contribute to the enrichment of fluoride in groundwater. In situ treatment of SHFGW may be an effective approach to manage high SHFGW in the Jiaolai Basin. Since soil fluoride in high-fluoride areas can leach into groundwater and migrate with runoff, the construction of ditches can shorten the runoff of shallow groundwater and accelerate groundwater loss, resulting in the loss of SHFGW from high-fluoride areas through river outflow. The groundwater level will be reduced, thereby lowering the influence of evaporation on fluoride enrichment in shallow groundwater. The results of this study can act a reference for further research on in situ treatment for high-fluoride groundwater

Study of the Effects of Land Use on Hydrochemistry and Soil Microbial Diversity

The objectives of this study were to compare the influence of land use, to determine which land has an impact on hydrochemistry and to clarify the impact of land use on soil microbial diversity and the correlation between hydrochemistry and soil microbial diversity. The impacts were assessed through chemical and biological data from 4 land-use groups. The results showed that soil microbial diversity and water chemical composition were different under different land uses. There was a strong correlation between the main hydrochemical components under different land uses, and the M03 had the highest correlation. The Shannon index was the largest for M01, the Simpson index was the smallest for M01, and the Chao1 and Ace indexes were the largest for M02. Actinobacteria, Proteobacteria and Acidobacteria were the dominant bacteria with different land uses, and some bacteria were present or absent depending on the land use. It was found that the soil CO2 content was different with different land uses. Soil CO2 content, hydrochemistry and soil microbial species were related to each other. A heatmap analysis showed that the F− and soil CO2 content showed a strong correlation with soil microorganisms and that the dominant bacteria were positively correlated. Under different land uses, hydrochemistry, soil CO2 and soil microorganisms interact with one another

Deficit drip irrigation improves kiwifruit quality and water productivity under rain-shelter cultivation in the humid area of South China

Comprehending crop responses to water deficit at different growth stages is crucial for developing effective irrigation strategies. Different water deficit treatments (WDTs) were applied to the kiwifruit vines to investigate the effect of water deficit during different growth stages on the fruit quality, yield, and water productivity (WP); subsequently, the technique for order preference by similarity to an ideal solution method (TOPSIS) was employed to determine optimal treatments for kiwifruit cultivation. A total of 17 irrigation treatments were applied, including one control treatment (CTL, full irrigation) and four WDTs (denoted as D15%, D25%, D35%, and D45% respectively) during the bud burst to leafing (I), flowering to fruit set (II), fruit expansion (III), and fruit maturation (IV) stages. Results showed that WDTs during I, II, III, and IV decreased evapotranspiration (ET) over the whole growth period of kiwifruit vines by 1.2–3.8, 1.5–4.4, 4.7–14.3, and 6.9–21.3% compared with CTL, respectively. WDTs during stages I and II increased fruit volume (Vf) and fruit weight (FW), while exhibiting no significant impact on yield, WP, and chemical quality of kiwifruit. WDTs during stage III improved fruit firmness (Fn), total soluble solids (TSS), and titratable acidity (TA); however, it also caused severe reduction in Vf, FW, yield, and WP. Appropriate WDTs during stage IV significantly improved Fn, TSS, TA, vitamin C (Vc), and WP without compromising Vf, FW, and yield of kiwifruit. The IV-D25% treatment was determined to be the optimal treatment for improving fruit quality and WP of kiwifruit while maintaining yield, which increased TSS, TA, Vc, and WP by 9.1, 6.1, 19.2, 4.6%, respectively; the combination of D25%, D25%, full irrigation, and D25% treatments during stages I, II, III, and IV should be a viable irrigation strategy to simultaneously achieve high yield, quality, and WP of kiwifruit

Genetic Algorithm-Optimized Extreme Learning Machine Model for Estimating Daily Reference Evapotranspiration in Southwest China

Reference evapotranspiration (ET0) is an essential component in hydrological and ecological processes. The Penman–Monteith (PM) model of Food and Agriculture Organization of the United Nations (FAO) model requires a number of meteorological parameters; it is urgent to develop high-precision and computationally efficient ET0 models with fewer parameter inputs. This study proposed the genetic algorithm (GA) to optimize extreme learning machine (ELM), and evaluated the performances of ELM, GA-ELM, and empirical models for estimating daily ET0 in Southwest China. Daily meteorological data including maximum temperature (Tmax), minimum temperature (Tmin), wind speed (u2), relative humidity (RH), net radiation (Rn), and global solar radiation (Rs) during 1992–2016 from meteorological stations were used for model training and testing. The results from the FAO-56 Penman–Monteith formula were used as a control group. The results showed that GA-ELM models (with R2 ranging 0.71–0.99, RMSE ranging 0.036–0.77 mm·d−1) outperformed the standalone ELM models (with R2 ranging 0.716–0.99, RMSE ranging 0.08–0.77 mm·d−1) during training and testing, both of which were superior to empirical models (with R2 ranging 0.36–0.91, RMSE ranging 0.69–2.64 mm·d−1). ET0 prediction accuracy varies with different input combination models. The machine learning models using Tmax, Tmin, u2, RH, and Rn/Rs (GA-ELM5/GA-ELM4 and ELM5/ELM4) obtained the best ET0 estimates, with R2 ranging 0.98–0.99, RMSE ranging 0.03–0.21 mm·d−1, followed by models with Tmax, Tmin, and Rn/Rs (GA-ELM3/GA-ELM2 and ELM3/ELM2) as inputs. The machine learning models involved with Rn outperformed those with Rs when the quantity of input parameters was the same. Overall, GA-ELM5 (Tmax, Tmin, u2, RH and Rn as inputs) outperformed the other models during training and testing, and was thus recommended for daily ET0 estimation. With the estimation accuracy, computational costs, and availability of input parameters accounted, GA-ELM2 (Tmax, Tmin, and Rs as inputs) was determined to be the most effective model for estimating daily ET0 with limited meteorological data in Southwest China

Meta-Analysis of Factors Affecting C-N Fractions and Yield of Paddy Soils by Total Straw Return and N Fertilizer Application

The effective use of nutrient-rich crop straw is an important way to use resources efficiently and to sustain agricultural development. This meta-analysis study collected and analyzed the data of 6788 observations published in 238 peer-reviewed papers to investigate differences in soil C-N fractions and yields of paddy soils under different straw-return amounts. This large dataset was also used to quantify the degree of influence of factors such as climate characteristics, soil properties, N fertilizer application rates, straw-rotting agent addition, rice varieties, and straw return methods. The results showed that straw return amounts improved soil alkaline-hydrolysable N (7%), total N (10%), organic C (11%), the C:N ratio (8%), rice N accumulation (12%), and overall yield (18%). The most significant effect was in northeast China fields for total soil nitrogen (TN) content and yield with increases of 13% and 22%, respectively. We also found more effective N utilization and a greater rice yield when 220–260 kg ha−1 N fertilizer was applied with 20–30 kg ha−1 straw-rotting agent with the total amount of straw return. These findings have important implications for choosing appropriate conditions and field management practices and to improve rice yield in China