• Energy Research
• Closed Access close
• Open Source close
• CN close
• EU close
• Aurora Universities Network close

Bioelectrochemical systems (BESs) are hybrid systems using electroactive bacteria and solid electrodes, which serve as electron donor or acceptor for microorganisms. When forming a biofilm on the electrode, bacteria secrete extracellular polymeric substances (EPSs). However, EPS excretion of electroactive biofilms in BES has been rarely studied so far. Consequently, the aim of this study is to develop a routine including the electrochemical cultivation, biofilm harvesting, fractionation, and biochemical analysis of the EPS secreted by Geobacter sulfurreducens under electroactive conditions. G. sulfurreducens was cultivated in microbial fuel cell mode on graphite-based electrodes polarized to +400 mV versus Ag/AgCl for 8 d. A maximum current density of 172 ± 29 μA cm-2 was reached after 7 d. The EPS secreted from the biofilms were harvested and fractioned into soluble, loosely bound, and tightly bound EPS and biochemically analyzed. Electroactive cultures secreted significantly more EPSs compared to cells grown under standard heterotrophic conditions (fumarate respiration). With 116 pg per cell, the highest amount of EPSs was measured for the soluble EPS fraction of G. sulfurreducens using anodic respiration, followed by the tightly bound (18 pg cell-1) and loosely bound (11 pg cell-1) fractions of the EPS. Proteins were found to dominate all EPS fractions of the biofilms grown under electrochemical conditions. To the best of the authors' knowledge, these experiments are the first approach toward a complete analysis of the main EPS components of G. sulfurreducens under anode-respiring conditions.

Energy supply is a global hot topic. The social and political pressure forces a higher percentage of energy supplied by renewable resources. The production of renewable energy in form of biomethane can be increased by co-substrates such as municipal biowaste. However, a demand-driven energy production or its storage needs optimisation, the option to store the substrate with its inherent energy is investigated in this study. The calorific content of biowaste was found unchanged after 45 d of storage (19.9±0.19 kJ g(-1) total solids), and the methane yield obtained from stored biowaste was comparable to fresh biowaste or even higher (approx. 400 m(3) Mg(-1) volatile solids). Our results show that the storage supports the hydrolysis of the co-substrate via acidification and production of volatile fatty acids. The data indicate that storage of biowaste is an efficient way to produce bioenergy on demand. This could in strengthen the role of biomethane plants for electricity supply the future.

Livestock farming and its products provide a diverse range of benefits for our day-to-day life. However, the ever-increasing demand for farmed animals has raised concerns about waste management and its impact on the environment. Worldwide, cattle produce enormous amounts of manure, which is detrimental to soil properties if poorly managed. Waste management with insect larvae is considered one of the most efficient techniques for resource recovery from manure. In recent years, the use of black soldier fly larvae (BSFL) for resource recovery has emerged as an effective method. Using BSFL has several advantages over traditional methods, as the larvae produce a safe compost and extract trace elements like Cu and Zn. This paper is a comprehensive review of the potential of BSFL for recycling organic wastes from livestock farming, manure bioconversion, parameters affecting the BSFL application on organic farming, and process performance of biomolecule degradation. The last part discusses the economic feasibility, lifecycle assessment, and circular bioeconomy of the BSFL in manure recycling. Moreover, it discusses the future perspectives associated with the application of BSFL. Specifically, this review discusses BSFL cultivation and its impact on the larvae's physiology, gut biochemical physiology, gut microbes and metabolic pathways, nutrient conservation and global warming potential, microbial decomposition of organic nutrients, total and pathogenic microbial dynamics, and recycling of rearing residues as fertilizer.

Abstract Harmful SO2 largely originates from coal and oil combustions, but in some areas the biomass burning contribution could not be ignored. Here, we evaluated SO2 emissions from biomass burning (BB-SO2) with largely focusing on regional difference and temporal trends in the relative contributions of biomass burning from different sectors. Globally, the biomass burning emitted 4.26 (3.20–6.20) Tg SO2 in 2014, contributing 4.0% of the total SO2 emissions stemming from anthropogenic sources and natural open fires. But in some African and South Asian countries, biomass burning was a major source of SO2 with the contribution as high as 80–90%. Regarding sector contributions of biomass SO2, open fires contributed nearly half, followed by the residential sector (~29%) on the global scale, however, substantially different profiles were revealed across countries. Residential sector is the largest anthropogenic BB-SO2 source in the developing countries, while in the developed countries, industry and energy production were the two main anthropogenic BB-SO2sources. From 1960 to 2014, biomass SO2 emission, either the absolute amount or the relative contribution to the total, increased in the U.S. and Europe, and the contributions were over 20% in some countries. The biomass burning SO2 emission showed an increasing trend in India and a unimodal change in China, while a decreasing trend in the relative contributions were revealed in these two largest developing countries, which were 2.7% and 0.8%, respectively in 2014. With unignorable biomass burning contribution to SO2, as well as other hazardous air pollutants, in some regions, it is suggested that in assessing climate and health impacts of promoted biomass utilization when phasing out of fossil fuels, multiple components should be co-evaluated.

Abstract In this study, a novel interlaced microchannel with a “cold water-hot water-cold water” counterflow arrangement was designed. The influences of microchannel configurations on the thermal and hydraulic performance were studied by comparing the proposed microchannel configuration with parallel and traditional spiral configurations. The results showed that the effective heat transfer area of the interlaced microchannel was 6.4 and 8.4 times that of the parallel and spiral configurations, respectively. For interlaced microchannels, the maximum temperature difference between the cross sections was 0.07 °C, and the temperature rise along the flow direction was only 6 °C. When the Reynolds number was 492, the Nusselt number of the interlaced microchannels was 2 and 10 times that of the parallel and spiral microchannels, respectively. The heat transfer performance of interlaced microchannels was improved by 83.46% compared with that in the literature. The influence of microchannel configurations on the pressure drop and the entrance length were negligible. The interlaced microchannel exhibited its lowest thermal resistance of 0.015 °C/W and lowest entropy production of 22.6 W/ °C at a Reynolds number of 492. The heat transfer enhancement coefficient of the interlaced microchannel and parallel microchannel were 5 and 2.8 times that of the traditional spiral microchannel, respectively. The maximum heat load of loop heat pipe was enhanced by 4 times with the integration of interlaced microchannel as the condenser.

Ammonia (NH3), one of the most promising carbon-free fuels, has received great research interest. In particular, NH3 is often blended with hydrocarbon fuels to achieve desired combustion characteristics. However, NH3 addition could affect soot formation, which has not been adequately understood. In this study, the effect of NH3 on the growth of polycyclic aromatic hydrocarbons (PAHs) is investigated with the reactive force field molecule dynamics (ReaxFF MD) simulations and quantum chemistry calculations. The simulation results indicate that NH3 addition slows down the growth of large carbon-containing species in the C2H4/O2 system. Novel path with HCN addition is discovered in the PAH growth, which inhibits the PAH growth compared to the conventional Hydrogen-Abstraction-Carbon-Addition (HACA) path via C2H2 addition. Moreover, quantum chemical calculations verified the rationality of this addition path and explained its inhibition on PAH growth by calculating the heat of reactions and reaction energy barriers. According to the present study, NH3 also has an inhibitory effect on both the HCN addition path and C2H2 addition path by providing H atoms to promote the generation of PAH radicals back to PAH molecules, and this effect is more significant for the C2H2 addition path. Results from the study provide a fundamental insight for the inhibition of PAH growth due to the NH3 addition from an atomistic insight, which helps to improve the understanding of the combustion of blends of NH3 and hydrocarbon fuels.

Alcohol is a well-known risk factor for hepatocellular carcinoma. Autophagy plays a dual role in liver cancer, as it suppresses tumor initiation and promotes tumor progression. Transcription factor EB (TFEB) is a master regulator of lysosomal biogenesis and autophagy, which is impaired in alcohol-related liver disease. However, the role of TFEB in alcohol-associated liver carcinogenesis is unknown. Liver-specific Tfeb knockout (KO) mice and their matched wild-type (WT) littermates were injected with the carcinogen diethylnitrosamine (DEN), followed by chronic ethanol feeding. The numbers of both total and larger tumors increased significantly in DEN-treated mice fed ethanol diet than in mice fed control diet. Although the number of tumors was not different between WT and L-Tfeb KO mice fed either control or ethanol diet, the number of larger tumors was less in L-Tfeb KO mice than in WT mice. No differences were observed in liver injury, steatosis, inflammation, ductular reaction, fibrosis, and tumor cell proliferation in DEN-treated mice fed ethanol. However, the levels of glypican 3, a marker of malignant hepatocellular carcinoma, markedly decreased in DEN-treated L-Tfeb KO mice fed ethanol in comparison to the WT mice. These findings indicate that chronic ethanol feeding promotes DEN-initiated liver tumor development, which is attenuated by genetic deletion of hepatic TFEB.

In this study, the energy, exergy, exergoeconomic and exergoenvironmental (4E) analyses of a cogeneration system that combines photovoltaic thermal panels (PV/T), evacuated tube solar collectors, an organic Rankine cycle (ORC) and energy storage systems are performed. The cogeneration model is built to meet the load demand of independent houses in remote areas and avoids excessive consumption of traditional energy and environmental pollution. Here, the exergoenvironmental analysis adopts the Eco-indicator-99 method and the all life cycle assessment method is used to calculate the environmental impact of each component. Two comparative studies are conducted to the 4E analyses. The first one compares the comprehensive performance of the battery storage and hydrogen production for energy storage. The results indicate that the cogeneration system using both batteries and hydrogen production for energy storage has the best overall performance. According the exergoeconomic and exergoenvironmental analyses, its environmental impact is 23.6% lower than the cogeneration system using batteries alone and the PV/T can be fully utilized. In addition, the total cost rate is 6.2% lower than the cogeneration system using hydrogen production alone. The second case investigates the effect of adding the evacuated tube solar collectors between the PV/T and ORC on the cogeneration system. The analysis results demonstrate that the evacuated tube solar collectors can increase the heat source temperature of the ORC to increase the power generation of the ORC by 37.14%; however, the total cost rate of the cogeneration system increases by 3.7% and the environmental impact rate increases by 19.8%.