Search results for "Amination"

Assessing the transfer of pentachlorophenol through soil columns using 13[C]isotope

2002

Abstract The transfer of organic pollutants was studied through soil columns using 13 [C]-labelled pentachlorophenol (PCP) as a model compound. The organic carbon content and the 13 [C]/ 12 [C] ratio were measured in two soil sections, 0–3 cm and 3–6 cm, and in percolated water using an Elemental Analyser coupled with a Magnetic Mass Sector. The mass balance of carbon was evaluated and the amount of PCP was calculated in each compartment of the soil–water systems. The results show that more than 80% of the PCP-derived 13 [C] remained in the upper layer of the soil column. Approximately 20% was transferred to the lower soil layer, and less than 1% was found in the water leachates. The 13 [C]…

Torrefaction and pyrolysis of metal-enriched poplars from phytotechnologies: Effect of temperature and biomass chlorine content on metal distribution…

2017

Abstract Torrefaction (290 °C) and pyrolysis (450 and 800 °C) trials were performed at pilot scale with a patented reactor on metal-enriched poplars from a contaminated soil managed by phytotechnologies and poplars cultivated on uncontaminated soil, for comparison. This study emphasized the influence of temperature on end-product yield, metal distribution in end-products and metal behavior. Results showed that the evolution of the end-product yield, i.e. biochar, bio-oil and gas fractions, was depending on temperature rather than other parameters such as the origin or metal content of the tested poplars. Torrefaction decreased the processed poplars weight, leading to metal-enriched torrefie…

Etude et caractérisation de l'état " Viable mais Non Cultivable " chez Brettanomyces, une levure d'altération des vins : nouvel outil de détection et…

2011

The viable but not culturable (VBNC) state has been studied in detail in bacteria. It has been suggested that the VBNC state also exists in eukaryote cells, such as wine yeasts, including Brettanomyces in particular. We investigated the VBNC state in this yeast, focusing on the conditions for entry and exit, and the morphological and metabolic modifications associated with this state. We added sulfite (0.8 mg.L-1 molecular SO2) to induce the VBNC state. Increasing the pH of the medium inactivated the sulfite, allowing the cells to exit from the VBNC state and to become culturable again. In these conditions, we found that Brettanomyces VBNC cells were smaller than culturable cells, and that …

Microalgae community structure analysis based on 18S rDNA amplification from DNA extracted directly from soil as a potential soil bioindicator

2005

International audience; Soil algae are photosynthetically active microorganisms showing changeable community structure, depending on the soil type, the agricultural practices and the application of pesticides. To characterise algal community structure, molecular approaches complementary to classical microbiological approaches based on the isolation and the culture of soil algae are required. Our study describes a polymerase chain reaction (PCR) approach targeting algal 18S rDNA sequences of desoxyribonucleic acid (DNA) samples extracted either from unialgal eukaryotic microalgae culture, complex assemblages of microalgae populations or natural soil communities. Our first results showed that…

Enhanced isoproturon mineralisation in a clay silt loam agricultural soil

2005

International audience; 14C-ring-labelled isoproturon mineralisation was investigated in a French agricultural soil previously exposed to isoproturon. 50 different soil samples collected every 2 m along a transect of 100 m in length were treated one or two times with isoproturon under laboratory conditions and analysed by radiorespirometry. 94% of the soil samples showed a high ability to mineralise isoproturon with a relatively low variability in the cumulative percentage of mineralisation ranging from 30 to 51% of the initially added radioactivity for the samples treated once with the herbicide. About 45 to 67% of the initially added radioactivity was transformed into 14CO2 in soil sample…

Inactivation of lactococcal aromatic aminotransferase prevents the formation of flora aroma compounds from aromatic amino acids in semi-hard cheese

1999

The enzymatic conversion of aromatic amino acids to aroma compounds plays a role in the formation of an undesirable floral aroma in Cheddar-like cheeses. In lactococci, the first step of aromatic amino acid degradation is a transamination, catalysed by an aromatic aminotransferase (AraT). We observed previously that in vitro, araT inactivation prevented degradation of aromatic amino acids and decreased degradation of Met and Leu. In this study we evaluated the effect of araT inactivation in Lactococcus lactis on flavour development in St. Paulin-type cheese. The degradation of amino acids was monitored by using radiolabelled amino acids and the volatile compounds formed were analysed by GC-…

Influence de la biodégradation dans l’atténuation des pesticides sur un bassin versant viticole : potentialité des différents éléments du paysage et …

2013

Nos travaux ont montré que les différents compartiments d'un paysage viticole du site atelier de la Morcille (sol de la parcelle, bande enherbée et sédiments) connectés le long du continuum sol-eau, présentaient une aptitude à minéraliser le diuron. La capacité épuratrice de ces différents compartiments évolue en fonction du niveau d’exposition au contaminant. Ainsi la zone tampon exposée présente une meilleure aptitude à épurer le diuron que la zone tampon témoin. Les sédiments de la Morcille situés à proximité de la zone tampon présentent également une capacité épuratrice présentant un gradient amont-aval coïncidant avec le gradient amont-aval observé également pour la qualité chimique de…

Hydro-contamination fongique par Fusarium spp. en milieu hospitalier pendant une période de construction

2009

Les particules biotiques (pathogènes ou non)

2017

National audience

Écologie microbienne de la grotte de Lascaux

2009

National audience