Search results for "Aerobic"

Time trials versus time-to-exhaustion tests: Effects on critical power, W0, and oxygen-uptake kinetics

2018

Purpose: To investigate single-day time-to-exhaustion (TTE) and time-trial (TT) -based laboratory tests values of critical power (CP), W prime (W0), and respective oxygen-uptake-kinetic responses. Methods: Twelve cyclists performed a maximal ramp test followed by 3 TTE and 3 TT efforts interspersed by 60 min recovery between efforts. Oxygen uptake (VO 2) was measured during all trials. The mean response time was calculated as a description of the overall VO 2-kinetic response from the onset to 2 min of exercise. Results: TTE-determined CP was 279 ± 52 W, and TT-determined CP was 276 ± 50 W (P = .237). Values of W0 were 14.3 ± 3.4 kJ (TTE W0) and 16.5 ± 4.2 kJ (TT W0) (P = .028). While a hig…

Towards a microbial thermoelectric cell.

2013

Microbial growth is an exothermic process. Biotechnological industries produce large amounts of heat, usually considered an undesirable by-product. In this work, we report the construction and characterization of the first microbial thermoelectric cell (MTC), in which the metabolic heat produced by a thermally insulated microbial culture is partially converted into electricity through a thermoelectric device optimized for low ΔT values. A temperature of 41°C and net electric voltage of around 250–600 mV was achieved with 1.7 L baker’s yeast culture. This is the first time microbial metabolic energy has been converted into electricity with an ad hoc thermoelectric device. These results might…

Influence of Walking as Physiological Training to Improve Respiratory Parameters in the Elderly Population.

2022

Walking as physiological training is reported to be an effective activity in order to beneficially influence and slow the onset of aging in healthy elderly people. However, insufficient evidence exists on how walking influences lung function in seniors. In our study, we aim to evaluate the effect of different types of walking on lung function in healthy seniors. The PubMed, Web of Science, Scopus and EBSCO Essentials databases were searched, while the methodological quality was assessed by the RoB2 tool. A total of seven studies (RCTs) published between 2002–2022 that met the eligibility criteria were analysed in this review. All participants were older adults without any specific associate…

Sulfur isotope's signal of nanopyrites enclosed in 2.7 Ga stromatolitic organic remains reveal microbial sulfate reduction.

2018

18 pages; International audience; Microbial sulfate reduction (MSR) is thought to have operated very early on Earth and is often invoked to explain the occurrence of sedimentary sulfides in the rock record. Sedimentary sulfides can also form from sulfides produced abiotically during late diagenesis or metamorphism. As both biotic and abiotic processes contribute to the bulk of sedimentary sulfides, tracing back the original microbial signature from the earliest Earth record is challenging. We present in situ sulfur isotope data from nanopyrites occurring in carbonaceous remains lining the domical shape of stromatolite knobs of the 2.7-Gyr-old Tumbiana Formation (Western Australia). The anal…

Effect of ADH II Deficiency on the Intracellular Redox Homeostasis in Zymomonas mobilis

2011

Mutant strain of the facultatively anaerobic, ethanol-producing bacteriumZymomonas mobilis, deficient in the Fe-containing alcohol dehydrogenase isoenzyme (ADH II), showed impaired homeostasis of the intracellular NAD(P)H during transition from anaerobic to aerobic conditions, and also in steady-state continuous cultures at various oxygen supplies. At the same time, ADH II deficiency in aerobically grown cells was accompanied by a threefold increase of catalase activity and by about 50% increase of hydrogen peroxide excretion. It is concluded that ADH II under aerobic conditions functions to maintain intracellular redox homeostasis and to protect the cells from endogenous hydrogen peroxide.

Validation of a novel automatic deposition of bacteria and yeasts on MALDI target for MALDI-TOF MS-based identification using MALDI Colonyst robot

2017

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) -based identification of bacteria and fungi significantly changed the diagnostic process in clinical microbiology. We describe here a novel technique for bacterial and yeast deposition on MALDI target using an automated workflow resulting in an increase of the microbes' score of MALDI identification. We also provide a comparison of four different sample preparation methods. In the first step of the study, 100 Gram-negative bacteria, 100 Gram-positive bacteria, 20 anaerobic bacteria and 20 yeasts were spotted on the MALDI target using manual deposition, semi-extraction, wet deposition onto 70% formic …

Enhancing methane production from lignocellulosic biomass by combined steam-explosion pretreatment and bioaugmentation with cellulolytic bacterium

2017

Background Biogas production from lignocellulosic biomass is generally considered to be challenging due to the recalcitrant nature of this biomass. In this study, the recalcitrance of birch was reduced by applying steam-explosion (SE) pretreatment (210 °C and 10 min). Moreover, bioaugmentation with the cellulolytic bacterium Caldicellulosiruptor bescii was applied to possibly enhance the methane production from steam-exploded birch in an anaerobic digestion (AD) process under thermophilic conditions (62 °C). Results Overall, the combined SE and bioaugmentation enhanced the methane yield up to 140% compared to untreated birch, while SE alone contributed to the major share of methane enhancem…

Anaerobic and sequential anaerobic-aerobic treatments of municipal landfill leachate at low temperatures

1996

Abstract Anaerobic treatment of municipal landfill leachate (COD 1–4 g l −1 , NH 4 -N c. 0.16 g l −1 ) was studied at 11 and 24°C by using laboratory-scale UASB and hybrid reactors. Aerobic post-treatment of the anaerobically treated leachate was also studied at 24°C using an activated-sludge process. In the 11°C reactors, a COD removal of up to 60–65% was obtained with 1.5-2 day HRT and 0.7-1.5 kg COD m −3 day −1 organic loading rates. At 24°C, a COD removal of up to 75% was achieved with a 10 h HRT. The highest organic loading rate applied was 10 kg COD m −3 day −1 at 24°C. Inorganic material accumulated in the reactor sludges at both temperatures. However, the specific methanogenic activ…

Energy Transduction in Anaerobic Prokaryotes

2004

Optimization of acetate production from citrus wastewater fermentation

2021

Abstract Citrus wastewater is a sugar-rich waste stream suitable for the recovery of energy of material from its treatment. In this study, fermentation of citrus wastewater was carried out to assess the optimal conditions to maximize the bioconversion of the organic substrate into acetate. Unbalanced nutrient (C: N: P 200:0.1:0.1) enabled the highest acetate production. The presence of the particulate organic fraction enabled to obtain a higher acetate concentration regardless the initial COD concentration. Initial pH values higher than 5 did not cause substantial differences on the maximum bioconversion of COD into acetate in Trial 3, whereas pH lower than 5 hindered the hydrolysis process…