Search results for "anaerobic"

Aerobic catabolism and respiratory lactate bypass in Ndh-negative Zymomonas mobilis

2018

Ability to ferment in the presence of oxygen increases the robustness of bioprocesses and opens opportunity for novel industrial setups. The ethanologenic bacterium Zymomonas mobilis performs rapid and efficient anaerobic ethanol fermentation, yet its respiratory NADH dehydrogenase (Ndh)-deficient strain (ndh-) is known to produce ethanol with high yield also under oxic conditions. Compared to the wild type, it has a lower rate of oxygen consumption, and an increased expression of the respiratory lactate dehydrogenase (Ldh). Here we present a quantitative study of the product spectrum and carbon balance for aerobically growing ndh-. Ldh-deficient and Ldh-overexpressing ndh- strains were con…

Physical exercise increases adult hippocampal neurogenesis in male rats provided it is aerobic and sustained

2016

Key points Aerobic exercise, such as running, enhances adult hippocampal neurogenesis (AHN) in rodents. Little is known about the effects of high-intensity interval training (HIT) or of purely anaerobic resistance training on AHN. Here, compared with a sedentary lifestyle, we report a very modest effect of HIT and no effect of resistance training on AHN in adult male rats. We found the most AHN in rats that were selectively bred for an innately high response to aerobic exercise that also run voluntarily and increase maximal running capacity. Our results confirm that sustained aerobic exercise is key in improving AHN. Abstract Aerobic exercise, such as running, has positive effects on brain …

2020

Background To date, microRNAs (miRs) carried in extracellular vesicles (EVs) in response to exercise have been studied in blood but not in non-invasively collectable body fluids. In the present study, we examined whether six exercise-responsive miRs, miRs-21, -26, -126, -146, -221, and -222, respond to acute endurance exercise stimuli of different intensities in sweat. Methods We investigated the response of miRs isolated from sweat and serum EVs to three endurance exercise protocols: (1) maximal aerobic capacity (VO2max ), (2) anaerobic threshold (AnaT), and (3) aerobic threshold (AerT) tests. Sauna bathing was used as a control test to induce sweating through increased body temperature in…

C4 ‐dicarboxylates and l ‐aspartate utilization by Escherichia coli K‐12 in the mouse intestine: l ‐aspartate as a major substrate for fumarate respi…

2021

C4-dicarboxylates, such as fumarate, L-malate and L-aspartate represent substrates for anaerobic growth of Escherichia coli by fumarate respiration. Here, we determined whether C4-dicarboxylate metabolism as well as fumarate respiration contribute to colonization of the mammalian intestinal tract. Metabolite profiling revealed that the murine small intestine contained high and low levels of L-aspartate and L-malate, respectively, whereas fumarate was nearly absent. Under laboratory conditions, addition of C4-dicarboxylate at concentrations corresponding to the levels of the C4-dicarboxylates in the small intestine (2.6 mMol/kg dry weight) induced the dcuBp-lacZ reporter gene (67% of maximal…

Disentangling the effects of methanogen community and environment on peatland greenhouse gas production by a reciprocal transplant experiment

2020

Microbial community analysis, influence of reactor hybridation and effect of the proportion of glycol ethers/ethanol mixtures in EGSB reactors

2018

Antecedentes La emisión de compuestos orgánicos volátiles (COVs) puede causar diferentes problemas en la salud pública y en el medio ambiente, actuando como contaminantes primarios y permitiendo la formación de contaminantes secundarios como el ozono troposférico. Debido a estos problemas, la emisión de COVs está limitada en muchos países tales como EEUU o los pertenecientes a la Unión Europea, en este caso regulado por la directiva 2010/75/EU. Debido al uso de disolventes en su proceso productivo, la industria flexográfica es uno de los sectores que más contribuye a la emisión de este tipo de compuestos, y las técnicas biológicas han sido consideradas como una de las mejores disponibles pa…

Considering syntrophic acetate oxidation and ionic strength improves the performance of models for food waste anaerobic digestion.

2021

Current mechanistic anaerobic digestion (AD) models cannot accurately represent the underlying processes occurring during food waste (FW) AD. This work presents an update of the Anaerobic Digestion Model no. 1 (ADM1) to provide accurate estimations of free ammonia concentrations and related inhibition thresholds, and model syntrophic acetate oxidation as acetate-consuming pathway. A modified Davies equation predicted NH3 concentrations and pH more accurately, and better estimated associated inhibitory limits. Sensitivity analysis results showed the importance of accurate disintegration kinetics and volumetric mass transfer coefficients, as well as volatile fatty acids (VFAs) and hydrogen up…

Bacterial community response to changes in a tri-trophic cascade during a whole-lake fish manipulation

2015

Microbial communities play a key role in biogeochemical processes by degrading organic material and recycling nutrients, but can also be important food sources for upper trophic levels. Trophic cascades might modify microbial communities either directly via grazing or indirectly by inducing changes in other biotic or in abiotic factors (e.g., nutrients). We studied the effects of a tri-trophic cascade on microbial communities during a whole-lake manipulation in which European perch (Perca fluviatilis) were added to a naturally fishless lake divided experimentally into two basins. We measured environmental parameters (oxygen, temperature, and nutrients) and zooplankton biomass and studied th…

Modeling the anaerobic treatment of sulfate rich urban wastewater. Application to AnMBR technology

2020

[EN] Although anaerobic membrane bioreactors (AnMBR) are a core technology in the transition of urban wastewater (UWW) treatment towards a circular economy, the transition is being held back by a number of bottlenecks. The dissolved methane released from the effluent, the need to remove nutrients (ideally by recovery), or the energy lost by the competition between methanogenic and sulfate-reducing bacteria (SRB) for the biodegradable COD have been identified as the main issues to be addressed before AnMBR becomes widespread. Mathematical modeling of this technology can be used to obtain further insights into these bottlenecks plus other valuable information for design, simulation and contro…

Modeling solid waste decomposition.

2004

The hydrolysis rate coefficients of sorted municipal waste were evaluated from the biochemical methane potential tests using non-linear regression. A distributed mathematical model of anaerobic digestion of rich (food) and lean (non-food) solid wastes with greatly different rates of polymer hydrolysis/acidogenesis was developed to describe the balance between the rates of hydrolysis/acidogenesis and methanogenesis. The model was calibrated using previously published experimental data [Biores. Technol. 52 (1995) 245] obtained upon various initial food waste loadings. Simulations of one- and two-stage digestion systems were carried out. The results showed that initial spatial separation of fo…