Search results for "Mesophile"
showing 10 items of 52 documents
Anaerobic membrane bioreactor (AnMBR) scale-up from laboratory to pilot-scale for microalgae and primary sludge co-digestion: Biological and filtrati…
2020
This research work proposes the scale-up evaluation in terms of biological and filtration performance from laboratory to pilot-scale of an anaerobic membrane bioreactor (AnMBR) co-digesting raw microalgae and primary sludge. Best operating conditions for this scale-up were energetically and economically assessed based on laboratory results. Economic balance showed 3% higher annual costs when operating a reactor at 100 d solids retention time (SRT) compared to 70 d SRT. Energetic balance showed a 5.5-fold increase in heat demand working at thermophilic temperature comparing to mesophilic. The AnMBR operating conditions were set at 70 d SRT and 35 °C. The pilot-scale and lab-scale co-digester…
Co-digestion of harvested microalgae and primary sludge in a mesophilic anaerobic membrane bioreactor (AnMBR): Methane potential and microbial divers…
2020
Abstract Anaerobic co-digestion of primary sludge and raw microalgae (Scenedesmus and Chlorella) was performed in a lab-scale semi-continuous anaerobic membrane bioreactor to assess the biological performance and identify the microbial community involved in the co-digestion process. The reactor was operated at 35 °C for 440 days, working at a solids retention time of 100 days. The system achieved 73% biodegradability and showed high stability in terms of pH and volatile fatty acids. An enriched microbial community was observed. Of the several phyla, Chloroflexi and Proteobacteria were the most abundant. Cellulose-degraders phyla (Bacteroidetes, Chloroflexi and Thermotogae) were detected. Sy…
Sphingomonas solaris sp. nov., isolated from a solar panel in Boston, Massachusetts
2020
Solar panel surfaces, although subjected to a range of extreme environmental conditions, are inhabited by a diverse microbial community adapted to solar radiation, desiccation and temperature fluctuations. This is the first time a new bacterial species has been isolated from this environment. Strain R4DWNT belongs to the genus Sphingomonas and was isolated from a solar panel surface in Boston, MA, USA. Strain R4DWNT is a Gram-negative, non-motile and rod-shaped bacteria that tested positive for oxidase and catalase and forms round-shaped, shiny and orange-coloured colonies. It is mesophilic, neutrophilic and non-halophilic, and presents a more stenotrophic metabolism than its closest neighb…
Evaluation of microbiological and physico‐chemical parameters of retail ready‐to‐eat mono‐varietal salads
2019
An integrated microbiological and physico-chemical approach was applied to evaluate the decay of mono-varietal ready-to-eat escarole (Cichorium endivia var. latifolium) and red chicory (Cichorium intybus L. var. foliosum Hegi) during refrigeration. Total mesophilic microorganisms, including pseudomonads, and total psychrotrophic microorganisms were detected at high numbers in all samples just after packaging and at the expiry date. The dominant microbial populations analyzed by classical culture-dependent methods belonged to Pseudomonas and yeasts. Illumina sequencing identified Janthinobacterium lividum and Pseudomonas veronii as main species. Regarding the physico-chemical quality between…
Analysis of uncontrolled phosphorus precipitation in anaerobic digesters under thermophilic and mesophilic conditions.
2019
This study compares the operation of mesophilic and thermophilic anaerobic digestion of sewage sludge and their effects in uncontrolled phosphorus precipitation. The research has been carried out using a pilot plant consisting of two digesters of 1.6 m3 working volume, treating the mixed sludge of Alzira WWTP (Valencia, Spain). The digesters were operated in parallel, at different conditions: mesophilic (38 ± 2.0°C) and thermophilic (55 ± 2.5°C) temperatures and organic loading rates (OLR) ranging from 1.1 to 1.7 kg volatile solids (VS) m−3 d−1 and different hydraulic retention times (HRT) 20, 15 and 12 days. Uncontrolled precipitation was evaluated through P, Mg and Ca mass balances in bot…
Microbial Activation of Wooden Vats Used for Traditional Cheese Production and Evolution of Neoformed Biofilms.
2016
ABSTRACT Three Lactococcus lactis subsp. cremoris strains were used to develop ad hoc biofilms on the surfaces of virgin wooden vats used for cheese production. Two vats (TZ) were tested under controlled conditions (pilot plant), and two vats (TA) were tested under uncontrolled conditions (industrial plant). In each plant, one vat (TA1 and TZ1) was used for the control, traditional production of PDO Vastedda della Valle del Belìce (Vastedda) cheese, and one (TA2 and TZ2) was used for experimental production performed after lactococcal biofilm activation and the daily addition of a natural whey starter culture (NWSC). Microbiological and scanning electron microscopy analyses showed differenc…
Effect of long residence time and high temperature over anaerobic biodegradation of Scenedesmus microalgae grown in wastewater
2018
[EN] Anaerobic digestion of indigenous Scenedesmus spp. microalgae was studied in continuous lab-scale anaerobic reactors at different temperatures (35 degrees C and 55 degrees C), and sludge retention time - SRT (50 and 70 days). Mesophilic digestion was performed in a continuous stirred-tank reactor (CSTR) and in an anaerobic membrane bioreactor (AnMBR). Mesophilic CSTR operated at 50 days SRT only achieved 11.9% of anaerobic biodegradability whereas in the AnMBR at 70 days SRT and 50 days HRT reached 39.5%, which is even higher than the biodegradability achieved in the thermophilic CSTR at 50 days SRT (30.4%). Microbial analysis revealed a high abundance of cellulose-degraders in both re…
From grass to gas: microbiome dynamics of grass biomass acidification under mesophilic and thermophilic temperatures
2017
Background Separating acidification and methanogenic steps in anaerobic digestion processes can help to optimize the process and contribute to producing valuable sub-products such as methane, hydrogen and organic acids. However, the full potential of this technology has not been fully explored yet. To assess the underlying fermentation process in more detail, a combination of high-throughput sequencing and proteomics on the acidification step of plant material (grass) at both mesophilic and thermophilic temperatures (37 and 55 °C, respectively) was applied for the first time. Results High-strength liquor from acidified grass biomass exhibited a low biodiversity, which differed greatly depen…
Fermentation of Nocellara Etnea table olives by functional starter cultures at different low salt concentrations
2018
Nocellara Etnea is one of the main Sicilian cultivars traditionally used to produce both olive oil and naturally fermented table olives. In the present study, the effect of different salt concentrations on physico-chemical, microbiological, sensorial, and volatile organic compounds (VOCs) formation was evaluated in order to obtain functional Nocellara Etnea table olives. The experimental design consisted of 8 treatments as follow: fermentations at 4, 5, 6, and 8% of salt with (E1-E4 samples) and without (C1-C4 samples) the addition of starters. All the trials were carried out at room temperature (18 +/- 2 degrees C) and monitored for an overall period of 120 d. In addition, the persistence …
Shelf life evaluation of fresh-cut red chicory subjected to different minimal processes
2018
Abstract Microbiological, chemical and physical parameters of minimally processed red chicory (Cichorium intybus L.) subjected to two different transformation processes were investigated. A classic ready-to-eat (RTE) process (P1) and a production without cutting (P2) were monitored during refrigerated (4 °C) storage (15 d). Total mesophilic microorganisms, total psychrotrophic microorganisms and pseudomonads were detected at the highest cell densities in all samples. Presumptive Pseudomonas population dominated the cultivable microbial community of RTE red chicory and were characterized genetically. Twenty-two randomly amplified polymorphic DNA (RAPD) types were investigated by 16S rRNA gen…