Search results for "microorganism"

Genome sequence of the butanol hyperproducer Clostridium saccharoperbutylacetonicum N1-4

2013

2 p.

Exploring the yeast biodiversity of green table olive industrial fermentations for technological applications

2011

In recent years, there has been an increasing interest in identifying and characterizing the yeast populations associated with diverse types of table olive elaborations because of the many desirable technological properties of these microorganisms. In this work, a total of 199 yeast isolates were directly obtained from industrial green table olive fermentations and genetically identified by means of a RFLP analysis of the 5.8S-ITS region and sequencing of the D1/D2 domains of the 26S rDNA gene. Candida diddensiae, Saccharomyces cerevisiae and Pichia membranifaciens were the most abundant yeast species isolated from directly brined Aloreña olives, while for Gordal and Manzanilla cultivars th…

Biology of Microorganisms on Grapes, in Must and in Wine

2017

Maintenance of Wine-Associated Microorganisms

2008

A great variety of microorganisms growing on grapes, in must, or in wine have been isolated, which also have an influence on wine quality. They belong to acidtolerant microorganisms such as lactic acid bacteria, acetic acid bacteria, and yeasts. On grapes also molds can be found. The most important species for conversion of must into wine are the yeast Saccharomyces cerevisiae and the lactic acid bacterium Oenococcus oeni, which perform alcoholic and malolactic fermentation, respectively. Both species are used as starter cultures. A variety of techniques and media are available for the enrichment, culture, and preservation of these microorganisms. For selected species culture and preservati…

Recent Advances in Yeast Biomass Production

2011

Yeasts have been used by humans to produce foods for thousands of years. Bread, wine, sake and beer are made with the essential contribution of yeasts, especially from the species Saccharomyces cerevisiae. The first references to humans using yeasts were found in Caucasian and Mesopotamian regions and date back to approximately 7000 BC. However, it was not until 1845 when Louis Pasteur discovered that yeasts were microorganisms capable of fermenting sugar to produce CO2 and ethanol. Ancient practices were based on the natural presence of this unicellular eukaryote, which spontaneously starts the fermentation of sugars. As industrialisation increased the manufacture of fermented products, th…

Etude d'une microflore levurienne champenoise

1982

<p style="text-align: justify;">Pendant quatre années consécutives, on a suivi en Champagne, l'évolution de la microflore levurienne depuis la baie de raisin jusqu'au vin clair. Les résultats montrent une influence sensible sur la microflore, d'une part de certains traitements phytosanitaires et d'autre part des opérations liées à la vendange et au traitement des moûts. Grâce à un milieu de culture électif spécial, les auteurs ont amélioré la séparation des colonies de <em>S. cerevisiae</em> et de <em>S. bayanus</em>.</p><p style="text-align: justify;">+++</p><p style="text-align: justify;">For four consecutive years the evolution of yea…

Impact of distribution heterogeneity of microorganisms and 2,4-D on biodegradation processes in soil : experiment and modelling

2013

Impact of distribution heterogeneity of microorganisms and 2,4-D on biodegradation processes in soil : experiment and modelling. Conference on Pesticide Behaviour in Soils, Water and Air (York 2013)

Variability of pesticide mineralization in individual soil aggregates of millimeter size

2002

The aim of this study was to compare the 2,4-D mineralization in individual aggregates of millimeter size (3 size classes and 96 aggregates per size class). 14 CO 2 coming from the mineralization of 14 C ring-labeled 2,4-D and evolved by each aggregate incubated in microtiter plates was trapped with barium hydroxide on filters and measured using a Phosphorimager. We observed an important variability of mineralization in aggregates of each size class and in the different size classes of aggregates. The main factors responsible for these fluctuations could be a heterogeneous distribution of degrading microorganisms or of available carbon necessary for cometabolism.

A new tool to assess the ecotoxicological impact of β-triketone herbicides on soil microbial communities

2018

International audience; The β-triketone herbicides are post-emergence maize selective herbicides that have beenintroduced on the market, in replacement of atrazine, banned in Europe in 2004. Qualified as “eco-friendly”, since they are based on natural phytotoxin properties, these herbicides target an enzymeinvolved in carotenoid biosynthesis called 4-hydroxyphenylpyruvate dioxygenase (HPPD) encoded bythe hppd gene. The inhibition of this enzyme provokes bleaching symptoms, necrosis and death ofweeds.The hppd gene is not only find in eukaryotes such as plants, animals and humans but also inprokaryotes such as fungi, yeasts and bacteria. In recent studies, we showed that, within the soil bact…

Ultrafiltration as a Means to Investigate Copper Resistance Mechanisms in Soil Bacteria

1999

Copper is a trace element of major concern for agricultural soils. It exhibits a high toxicity against microorganisms and is widely introduced into soils as a component of pesticide treatments or urban wastes such as sewage sludges or refuse composts. In most French vineyards, “Bordeaux mixture” (copper sulfate) has been applied for more than a century, sometimes leading to copper concentrations in soils much higher than the threshold values (100 mg kg−1 in France). Microorganisms exposed to high concentrations of copper or other trace elements are known to develop resistance mechanisms and represent a suitable material for the study of such processes, both at a physiological and molecular …