Simultaneous nitrification and denitrification with electricity generation in dual‐cathode microbial fuel cells

BACKGROUND: Nitrogen removal using microbial fuel cells (MFCs) is of great interest owing to the potential benefits of bioenergy production. In this study, simultaneous nitrification and denitrification in dual‐cathode MFCs was investigated. RESULTS: The dual‐cathode MFCs investigated were capable of generating electricity and removing nitrogen, influenced by operating methods, nitrogen loading rates and external resistance. Depending on the ammonium concentration in the anode chamber, 84–97% of the ammonium nitrogen was removed via nitrification in the aerobic cathode. The removals of nitrate and total nitrogen were relatively low (～50%) at the influent ammonium concentration of 80 mg NH₄⁺‐N L^?1, but were significantly improved to more than 90% at a lower ammonium input (40 and 20 mg NH₄⁺‐N L^?1). When the electrode couples were electrically connected for different purposes, with high power output from the anode/aerobic cathode and high current generation from the anode/anoxic cathode, nitrogen removal was also improved. An investigation of aeration suggested that factors other than carbon supply, possibly inefficient reactor configuration, also limited the performance of the developed MFC. CONCLUSION: The experimental results demonstrated that the proposed pathway was feasible with effective nitrogen and organic removal. This study provided valuable information for the further development of a continuously operated dual‐cathode MFC system. Copyright © 2011 Society of Chemical Industry     

络合剂强化Fenton法修复有机污染土壤的功效与途径

综述了络合荆强化Fenton法修复有机污染土壤的功效与途径 指出了该领域今后的研究方向。     

Evaluation of pH‐treated fish sarcoplasmic proteins on rheological properties of fish myofibrillar protein mediated by microbial transglutaminase

Fish sarcoplasmic protein (SP) could be exploited in the water‐holding agent for fish protein gels, except that the gel strength is reduced. The adjustment of pH could modify protein interactions to overcome the inferior effect. Fish SP solutions were adjusted to pH 3 or 12, neutralised to pH 7 and lyophilised to be pH‐treated SPs. These SPs along with lyophilised untreated SP (Normal SP) were incorporated into fish myofibrillar protein (MP) with microbial transglutaminase (MTG). The denaturation temperature (T_d) of MP mixed with normal SP was 66 °C with the lowest shear stress value. The denaturation of MP mixed with pH‐treated SP reduced to be 57 °C, resulting in increased shear stress. The cooking loss of MP gel was reduced by adding pH‐treated SPs, while the breaking forces were similar to control. The result indicated that pH‐treated SPs could be used to reduce cooking loss of MTG‐mediated MP gels without affecting the gelling properties.     

Antimicrobial Activity of Parabens in Submicron Emulsions Stabilized with Lecithin

Antimicrobial efficacy of methyl and propylparaben combination as potential preservatives for submicron emulsions, and the effect of oil and lecithin concentration on the microbial growth were investigated. Parabens were ineffective in standard or doubled concentrations as per pharmacopoeial criteria. Poor growth inhibition and multiplication of reference strains point to protective and growth properties of submicron emulsions. No correlation was observed between oil/lecithin ratio and efficacy of parabens; partitioning of the latter into the oily phase and lipophilic domains could be the reason for such effect. Further studies are necessary to establish a stable and safe composition of such formulations.     

A novel approach to manage cloud security SLA incidents

Cloud computing is increasingly playing an important role in the service provisioning domain given the economic and technological benefits it offers. The popularity of cloud services is increasing but so are their customers’ concerns about security assurance and transparency of the Cloud Service Providers (CSPs). This is especially relevant in the case of critical services that are progressively moving to the cloud. Examples include the integrated European air traffic control system or public administrations through the governmental clouds. Recent efforts aim to specify security in cloud by using security service level agreements (secSLAs). However, the paucity of approaches to actually control the fulfillment of secSLAs and to react in case of security breaches, often results in distrust in cloud services. In this paper, we present a solution to monitor and enforce the fulfillment of secSLAs. Our framework is able to (a) detect occurrences that lead to unfulfillment of commitments, and (b) also provide mitigation to the harmful events that may or do compromise the validity of secSLAs.     

Mass balance and kinetic analysis of anaerobic microbial dechlorination of pentachlorophenol in a continuous flow column

A mass balance and kinetic investigation of anaerobic dechlorination of pentachlorophenol (PCP) was undertaken using an enriched microbial consortium in a laboratory scale continuous flow column, as a model microbial permeable reactive barrier. The chlorine balance showed that 50 µM PCP was largely dechlorinated to phenol with the formation of a small quantity of 3-chlorophenol as an intermediate metabolite (hydraulic retention time 7.6 days), and the chlorine removal efficiency reached 36 µM d^-1. When the initial PCP concentration was increased to 100 µM the chlorine removal efficiency increased 1.5 times. However, the dechlorination activity disappeared after 7.4 pore volumes (58 days), demonstrating the susceptibility of the dechlorination culture to high concentrations of PCP. Lactate released hydrogen as an electron donor during PCP dechlorination, with acetate, propionate, CO₂ and CH₄ as byproducts. The carbon balance showed that some of the organic carbon source (PCP, lactate) in the influent was converted to gas and utilized for biomass growth in addition to organic metabolites. The kinetic study was conducted in a batch culture and yielded 1.99 mg l^-1 biomass growth per unit of chlorine consumption (µM). The Monod equation was well fitted to the specific growth rate of 1.38 d^-1 and a half saturation constant of 0.29 µM. The organic chlorine removal rate in the batch culture was consistent with the results in the flow column, indicating the feasibility of and potential for in situ estimation and prediction through batch culture studies.     

Evaluation of various salt levels and different dairy proteins in combination with microbial transglutaminase on the quality characteristics of restructured pork ham

The objective of this study was to evaluate the quality characteristics of restructured pork hams (RH) manufactured with various salt levels (0.5%, 1.0%, and 1.5%) and different dairy proteins (sodium caseinate, SC and whey protein isolate, WPI; 1.0%) in combination with microbial transglutaminase (MTGase; 0.3%). Reduced‐salt (0.5% and 1.0%) RH resulted in reductions of moisture contents (%), textural springiness, cooking yield and most sensory preferences (P < 0.05). When dairy proteins in combination with MTGase were incorporated into the manufacture of RH, SC with MTGase was shown to reduce cooking loss (CL, %) and to increase the textural springiness and chewiness of RH, whereas WPI with MTGase increased textural springiness and chewiness, as well as the shear value of RH (P < 0.05). On the contrary, MTGase with dairy proteins improved the sensory preferences of reduced‐salt (1.0%) RH to give it similar sensory properties to those of the regular‐salt (1.5%) RH controls (CTL) (P > 0.05). The findings of this study demonstrated that the combination of 1.0% dairy proteins and 0.3% MTGase could affect improvements in the functional, textural and sensory properties of reduced‐salt (1.0%) RH.