Simulating Rumen Conditions Using an Anaerobic Dynamic Membrane Bioreactor to Enhance Hydrolysis of Lignocellulosic Biomass.

An anaerobic dynamic membrane bioreactor (AnDMBR) mimicking rumen conditions was developed to enhance the hydrolysis of lignocellulosic materials and the production of volatile fatty acids (VFAs) when treating food waste. The AnDMBR was inoculated with cow rumen content and operated at a 0.5 day hydraulic retention time, 2-4 day solids retention time, a temperature of 39 °C, and a pH of 6.3, characteristics similar to those of a rumen. Removal rates of neutral detergent fiber and acid detergent fiber of 58.9 ± 8.4 and 69.0 ± 8.6%, respectively, and a VFA yield of 0.55 ± 0.12 g VFA as chemical oxygen demand g volatile solids (VS)fed-1 were observed at an organic loading rate of 18 ± 2 kg VS m-3 day-1. The composition and activity of the microbial community remained consistent after biofilm disruption, bioreactor upset, and reinoculation. Up to 66.7 ± 5.7% of the active microbial populations and 51.0 ± 7.0% of the total microbial populations present in the rumen-mimicking AnDMBR originated from the inoculum. This study offers a strategy to leverage the features of a rumen; the AnDMBR achieved high hydrolysis and fermentation rates even when treating substrates different from those fed to ruminants.

Environmental life cycle assessment of treatment and management strategies for food waste and sewage sludge.

A consequential life cycle assessment (LCA) was utilized to compare the environmental impacts of food waste and sewage sludge management strategies. The strategies included a novel two-phase anaerobic digestion (AD) system and alternatives including landfill, waste-to-energy, composting, anaerobic membrane bioreactor, and conventional AD (wet continuous stirred-tank reactor [CSTR]). The co-management of food waste with sewage sludge was also considered for the two-phase AD system and for a conventional AD reactor. A multidimensional LCA approach was taken, considering the five-midpoint impact categories of global warming, smog, human health particulate, acidification, and eutrophication estimated using the U.S. EPA Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts. Co-management of food waste and sewage sludge using the novel two-phase AD system was shown to maximize energy recovery and had a net global warming benefit while reducing other environmental impacts compared with the alternative management strategies. It had similar relative environmental advantages across all categories as conventional AD, with the advantage of a smaller physical footprint. However, both approaches featured net environmental burdens when the background electric grid intensity fell below 0.25 kg CO2-eq kWh-1, as could be expected in a decarbonized electric future. Upgrading the biogas produced from AD to renewable natural gas can displace the use of fossil natural gas for other non-electricity energy requirements that are difficult to decarbonize and may extend the time period of significant environmental benefits of utilizing AD for organic waste management. Treatment of the nutrient-rich supernatant generated by the novel two-phase AD system could be an obstacle for utilities with stringent nutrient discharge limits. Future research and full-scale implementation are needed to demonstrate the benefits of the two-phase AD system predicted through this analysis.

Encapsulation technology for decentralized brewery wastewater treatment: A small pilot experiment.

The feasibility of implementing encapsulation technology for the biological anaerobic treatment of high-strength wastewater was investigated. The small pilot-scale wastewater treatment process, deployed at a local brewery, consisted of a 4-L fermenting first-stage reactor containing alginate-encapsulated fermenting microorganisms and a 30-L methanogenic second-stage reactor containing alginate-encapsulated anaerobic digester sludge (CH4E reactor). A parallel second-stage 30-L anaerobic membrane bioreactor (AnMBR) was operated for comparison. The first-stage reactor produced 40.4 ± 47.3% more volatile fatty acids than present in the influent wastewater. The CH4E reactor stared rapidly, with an off-gas methane content >60% after 14 days. It took >1 month for the AnMBR to achieve this performance. Nevertheless, the CH4E reactor performance declined relative to the AnMBR over time. This was thought to be a result of encapsulant leakage and the encapsulation of a non-ideal initial community. Further optimization is needed, but encapsulation shows promise for small-footprint anaerobic biological treatment applications.

Elevation of plasma tRNA fragments as a promising biomarker for liver fibrosis in nonalcoholic fatty liver disease.

Fibrotic tissue remodelling in nonalcoholic fatty liver disease (NAFLD) will probably emerge as the leading cause of end-stage liver disease in the coming decades, but the ability to diagnose liver fibrosis in NAFLD patients noninvasively is limited. The abnormal expression of tRNA-derived small RNA (tsRNA) in plasma provides a novel idea for noninvasive diagnosis of various diseases, however, the relationship between tsRNAs and NAFLD is still unknown. Here, we took advantage of small RNA-Seq technology to profile tsRNAs in NAFLD patients and found the ubiquitous presence of hepatic tsRNAs secreted into circulating blood. Verification in a cohort of 114 patients with NAFLD and 42 patients without NAFLD revealed that three tsRNAs (tRF-Val-CAC-005, tiRNA-His-GTG-001, and tRF-Ala-CGC-006) were significantly elevated in the plasma of NAFLD patients, and the expression level are associated with NAFLD activity score (calculated from 0 to 8) and fibrosis stage (scored from 0 to 4). In mouse models, we further found that increased plasma levels of these three tsRNAs were positively correlated with the degree of liver fibrosis. Our study potentially identifies a new class of NAFLD biomarkers and reveal the possible existence of tsRNAs in the blood that can be used to predict fibrogenesis risk in patients diagnosed with NAFLD.

Molecular investigation of infection sources and transmission chains of brucellosis in Zhejiang, China.

In the present study, a total of 7793 samples from 5 different types of hosts were collected and tested, with a seroprevalence of 2.4% (184/7793). Although the seroprevalence of human and animal brucellosis is relatively low, numbers of human brucellosis cases reported have increased continuously from 2004 to 2018. A total of 118 Brucella strains containing 4 biotypes were obtained, including Brucella melitensis bv.1 (n = 8) and bv.3 (n = 106), Brucella abortus bv.3 (n = 3) and bv.7 (n = 1). Twenty-one shared MLVA-16 genotypes, each composed of 2 to 19 strains obtained from different hosts, suggest the occurrence of a brucellosis outbreak epidemic with multiple source points and laboratory infection events. Moreover, 30 shared MLVA-16 genotypes were observed among 59.6% (68/114) B. melitensis isolates from Zhejiang and strains from other 21 different provinces, especially northern provinces, China. The analysis highlighted the imported nature of the strains from all over the northern provinces with a dominant part from the developed areas of animal husbandry. These data revealed a potential transmission pattern of brucellosis in this region, due to introduced infected sheep leading to a brucellosis outbreak epidemic, and eventually causing multiple laboratory infection events. It is urgent to strengthen the inspection and quarantine of the introduced animals.

Modeling alginate encapsulation system for biological hydrogen production.

Wastewater treatment using encapsulated biomass is a promising approach for high-rate resource recovery. Encapsulation matrices can be customized to achieve desired biomass retention and mass transport performance. This, in turn, facilitates treatment of different waste streams. In this study, a model was developed to describe calcium-alginate beads encapsulating hydrogen-producing biomass, with the goal of enabling appropriate a priori customization of the system. The model was based on a classic diffusion-reaction model, but also included the growth of encapsulated biomass and product inhibition. Experimental data were used to verify the model, which accurately described the effect of hydraulic retention time, bead size, and feed concentration on resource (hydrogen) recovery from brewery wastewater. Sensitivity analyses revealed that the hydrogen production rate was insensitive to substrate diffusivity and bead size, but sensitive to the substrate partition coefficient, initial encapsulated biomass concentration, and the total volume of beads in the reactor, demonstrating that this system was growth-limited rather than diffusion-limited under the tested conditions. Because the model quantifies the relationship between the hydrogen production rate and various input and operating parameters, it should be possible to extend the model to determine the most cost-effective system for optimal performance with a given waste stream.

[Risk Assessment of Snail Output Via the Mud Balls of Transplanted Seedlings in a Nursery Stock Park in Middle Region of Zhejiang Province].

Objective: To investigate the distribution of snails in a nursery stock park in the middle region of Zhejiang Province and assess the risk of snail output via the mud balls of transplanted seedlings, to provide scientific data for making strategies for snail control. Methods: We selected three species of seedlings including Osmanthus fragrans (a large tree), Camellia sasanqua (a small tree), and Purpus privet (a type of shrub) in a nursery stock park in a snail-positive middle region of Zhejiang Province during 2014-2016 to calculate the areas of regions with snails and the density of living snails. In 30 trees of each species, the distribution of snails within the seedlings ground diameter (radius of investigation, 100 cm for Osmanthus fragrans; 30 cm for Camellia Sasanqua and Purpus Privet) and in different soil layers (surface and superficial layers, 0-3 cm; deep layer, 3-10 cm) was assessed. In addition, the presence of snails in mud balls of 50 trees of Photinia fraseri (a small tree with high density of snails) was investigated to assess the risk of snail output. Results: In the planting areas of Osmanthus fragrans（3 930 m2）, Camellia sasanqua（2 000 m2）, and Purpus privet （1 700 m2）, the areas of snail-positive regions were 200, 900 and 800 m2, respectively, with the density of living snails being 0.08, 0.56 and 0.55/0.1 m2. For Osmanthus fragrans, Camellia sasanqua and Purpus privet, 238, 654 and 645 snails were detected respectively within their seedlings ground diameter, including 159（66.8%）, 461（70.5%） and 376 （58.3%） snails in the surface layer, respectively, which were significantly higher than those in the superficial and deep layers（P＜0.01）. Snails were found in all the 50 trees of Photinia fraseri（3 726 snails, 706 adult snails and 3 020 immature snails, 75 snails/tree on average）. Conclusion: There is a high density of snails in the nursery stock park in the middle region of Zhejiang Province. The snails are distributed mainly in the surface layer, suggesting a risk of snail output through mud balls.

Sleep-dependent neuroplastic changes during auditory perceptual learning.

Auditory perceptual learning is accompanied by a significant increase in the amplitude of sensory evoked responses on the second day of training. This is thought to reflect memory consolidation after the first practice session. However, it is unclear whether the changes in sensory evoked responses depend on sleep per se or whether a break between training sessions would sufficiently yield similar changes. To assess the relative contributions of sleep and passage of time (wakefulness) on the sensory evoked responses, we recorded auditory evoked fields using magnetoencephalography while participants performed a vowel segregation task in three different sessions separated by 12h over two consecutive days. The first two practice sessions were scheduled in the morning and evening of the same day for one group and the evening and morning of subsequent days for the other group. For each participant, we modeled the auditory evoked magnetic field with single dipoles in bilateral superior temporal planes. We then examined the amplitudes and latencies of the resulting source waveforms as a function of sleep and passage of time. In both groups, performance gradually improved with repeated testing. Auditory learning was paralleled by increased sustained field between 250 and 350ms after sound onset as well as sensory evoked fields around 200ms after sound onset (i.e., P2m amplitude) for sessions taking place on the same and different days, respectively. These neuromagnetic changes suggest that auditory learning involves a consolidation phase that occurs during the wake state, which is followed by a sleep-dependent consolidation stage indexed by the P2m amplitude.