References of "Berlemont, Renaud"
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See detailCellulase involvement in the bacterial cellulose biosynthesis
Delsaute, Maud ULg; Berlemont, Renaud ULg; Bauvois, Cédric et al

Poster (2012)

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See detailCellulase involvement in the cellulose biosynthesis of Pseudomonas stutzeri
Delsaute, Maud ULg; Berlemont, Renaud ULg; Paulus, Virginie et al

Poster (2011)

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See detailExploring the Antarctic soil metagenome as a source of novel cold-adapted enzymes and genetic mobile elements
Berlemont, Renaud ULg; Pipers; Delsaute, Maud ULg et al

in Revista Argentina de Microbiologia (2011)

Metagenomic library PP1 was obtained from Antarctic soil samples. Both functional and genotypic metagenomic screening were used for the isolation of novel cold-adapted enzymes with potential applications ... [more ▼]

Metagenomic library PP1 was obtained from Antarctic soil samples. Both functional and genotypic metagenomic screening were used for the isolation of novel cold-adapted enzymes with potential applications, and for the detection of genetic elements associated with gene mobilization, respectively. Fourteen lipase/esterase-, 14 amylase-, 3 protease-, and 11 cellulase-producing clones were detected by activity-driven screening, with apparent maximum activities around 35 °C for both amylolytic and lipolytic enzymes, and 35-55 °C for cellulases, as observed for other cold-adapted enzymes. However, the behavior of at least one of the studied cellulases is more compatible to that observed for mesophilic enzymes. These enzymes are usually still active at temperatures above 60 °C, probably resulting in a psychrotolerant behavior in Antarctic soils. Metagenomics allows to access novel genes encoding for enzymatic and biophysic properties from almost every environment with potential benefits for biotechnological and industrial applications. Only intI- and tnp-like genes were detected by PC R, encoding for proteins with 58-86%, and 58-73% amino acid identity with known entries, respectively. Two clones, BAC 27A-9 and BAC 14A-5, seem to present unique syntenic organizations, suggesting the occurrence of gene rearrangements that were probably due to evolutionary divergences within the genus or facilitated by the association with transposable elements. The evidence for genetic elements related to recruitment and mobilization of genes (transposons/integrons) in an extreme environment like Antarctica reinforces the hypothesis [less ▲]

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See detailFrom Metagenomes To Industrially Relevant Enzymes
Berlemont, Renaud ULg

Conference (2010, December)

Microorganisms living in extreme conditions have now been isolated from all type of extreme environments and numerous extremozymes originating from these organisms have been described and characterized ... [more ▼]

Microorganisms living in extreme conditions have now been isolated from all type of extreme environments and numerous extremozymes originating from these organisms have been described and characterized. Indeed, most of their potential resides in their enzymes. As stated by Huston in 2008 : “As environmental concerns arise, biological tools are increasingly replacing harsh chemical and physical means of processing materials and they even harbor promise for creating cost-effective sustainable energy sources. It is imperative that we continue investigating ways in which natural products can offer economical alternatives to traditional industrial processes”. In this context the search for valuable extremophiles and their integration in industrial processes will, without any doubt, fulfill these objectives in extending the use of microorganisms and of their products to unexpected transformations. Extensive investigations on extremophiles were therefore carried out for the reason that the large diversity of these organisms allowed to think that it is probably possible to find within them the appropriate isolate that produces the best possible product for a specific application. Of course these organisms have to be unravelled and their peculiarities sometimes render the culture conditions inappropriate. The recent emergence of the metagenomic approach has, however, modified the context and has now rendered possible the investigation of the world of non cultivable microorganisms. Indeed, recent advances of the metagenomic highlighted the underestimated gene diversity contained in environmental samples. In order to isolate new valuable cold adapted proteins, Antarctica soil metagenomic libraries were constructed and screened for various activities. Screenings were performed in industrially derived conditions, when feasible, and allowed the isolation of several new lipases/esterases, proteases, amylases, xylanases, … Hence, thorough characterization of the new enzymes is required prior their integration into industrial processes. We will discuss case-studies on three enzymes primarily isolated for the agro-food industry and displaying particular features. [less ▲]

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See detailInsights into the metagenomic approach : identification and characterization of cellulases involved in bacterial cellulose synthesis
Berlemont, Renaud ULg; Delsaute, Maud ULg; Galleni, Moreno ULg

Conference (2010, March 22)

the mining of an Antarctic soil sample by functional metagenomics allowed the isolation of a cold-adapted protein (RBcel1) that hydrolyzes only carboxymethyl cellulose. The new enzyme is related to family ... [more ▼]

the mining of an Antarctic soil sample by functional metagenomics allowed the isolation of a cold-adapted protein (RBcel1) that hydrolyzes only carboxymethyl cellulose. The new enzyme is related to family 5 of the glycosyl hydrolase (GH5) protein from Pseudomonas stutzeri (Pst_2494) and does not possess a carbohydrate-binding domain. The protein was produced and purified to homogeneity. RBcel1 displayed an endoglucanase activity, producing cellobiose and cellotriose, using carboxymethyl cellulose as a substrate. Moreover, the study of pH and the thermal dependence of the hydrolytic activity shows that RBcel1 was active from pH 6 to pH 9 and remained significantly active when temperature decreased (18% of activity at 10 1C). It is interesting that RBcel1 was able to synthetize non-reticulated cellulose using cellobiose as a substrate. Moreover, by a combination of bioinformatics and enzyme analysis, the physiological relevance of the RBcel1 protein and its mesophilic homologous Pst_2494 protein from P. stutzeri, A1501, was established as the key enzymes involved in the production of cellulose by bacteria. In addition, RBcel1 and Pst_2494 are the two primary enzymes belonging to the GH5 family involved in this process. [less ▲]

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Peer Reviewed
See detailCellulases catalysed cellulose polymerisation
Delsaute, Maud ULg; Berlemont, Renaud ULg; Renson, Thomas ULg et al

Poster (2010)

Detailed reference viewed: 33 (26 ULg)
See detailLes années métagénomiques au CIP, état des lieux et perspectives
Berlemont, Renaud ULg; Delsaute, Maud ULg

Scientific conference (2010)

Detailed reference viewed: 32 (15 ULg)
See detailCarbohydrate actives enzymes derived from metagenomes: from microbial ecology to enzymology
Berlemont, Renaud ULg; Galleni, Moreno ULg

in Li, Robert W. (Ed.) Metagenomics and its Applications in Agriculture, Biomedicine and Environmental Studies (2010)

In the last ten years, the intensive mining of various environmental metagenomes has led to the discovery of numerous new genes and corresponding putative enzymes. Some enzymes were isolated for their ... [more ▼]

In the last ten years, the intensive mining of various environmental metagenomes has led to the discovery of numerous new genes and corresponding putative enzymes. Some enzymes were isolated for their ability to hydrolyze carbohydrates, including starch, xylan, chitin and cellulose derivatives. The accurate characterization of these proteins highlights their variability and their biophysical adaptation in order to cope with specific environmental conditions. In this perspective, the sampling of extreme environments for metagenomic library construction resulted in the isolation of enzymes harbouring tailor made properties aimed at their implementation in various industrial processes. Although these new catalysts appear to be of particular interest for biotechnological applications, little is known about their physiological functions in their natural host. In the field of glycosides hydrolases, different functions have been suggested including both hydrolysis and synthesis of polymers. On the one hand, indeed in the environment microorganisms compete for ecological niches by producing enzymes active against vast ranges of substrates which allow them to thrive on various carbon sources. On the other hand, production of structural (cellulose) or reserve (glycogen) polymers by bacteria such as Gluconacetobacter sp. was reported. Polysaccharides can be associated with bacterial biofilm and feed stock, compounds that are required for bacteria to live in various environments. Interestingly, the synthesis of these polymers requires enzymes which act on carbohydrate including enzymes referred to as glycoside hydrolases acting as transglycosylases. In this chapter, a review of the representative glycoside hydrolases isolated by metagenomic and their possible physiological functions are presented. [less ▲]

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See detailExtremophiles
Berlemont, Renaud ULg; Gerday, Charles ULg

in Comprehensive Biotechnology (2010)

Extremophiles are organisms which inhabit environments characterized by properties harsh enough to hinder the survival of common cells. They are highly diversified and are classified on the basis of the ... [more ▼]

Extremophiles are organisms which inhabit environments characterized by properties harsh enough to hinder the survival of common cells. They are highly diversified and are classified on the basis of the main extreme property that prevails in the habitat. Six main categories can be distinguished: the thermophiles found in high temperature sites and which can tolerate temperatures sometimes close to that of the boiling point of water; the psychrophiles living in permanently cold habitats with temperatures sometimes well below the freezing point of water; the piezophiles, which tolerate pressure as high as 1000 atm; the halophiles supporting salt concentrations, in some cases, higher than 300gl–1; the acidophiles thriving well at pH sometimes close to zero; and the alkaliphiles, which, on the contrary, tolerate pH largely exceeding neutrality. These organisms are mainly microorganisms and they notably produce enzymes that are adapted to work in unusual conditions often required in biotechnological processes. This confers upon these organisms a very high potential. They are the target of a steadily increasing interest and are nowadays largely used in various industrial applications. [less ▲]

Detailed reference viewed: 21 (7 ULg)
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See detailInsights into bacterial cellulose biosynthesis by functional metagenomics on Antarctic soil samples.
Berlemont, Renaud ULg; Delsaute, Maud ULg; Pipers, Delphine ULg et al

in ISME Journal (The) (2009), 3(9), 1070-1081

In this study, the mining of an Antarctic soil sample by functional metagenomics allowed the isolation of a cold-adapted protein (RBcel1) that hydrolyzes only carboxymethyl cellulose. The new enzyme is ... [more ▼]

In this study, the mining of an Antarctic soil sample by functional metagenomics allowed the isolation of a cold-adapted protein (RBcel1) that hydrolyzes only carboxymethyl cellulose. The new enzyme is related to family 5 of the glycosyl hydrolase (GH5) protein from Pseudomonas stutzeri (Pst_2494) and does not possess a carbohydrate-binding domain. The protein was produced and purified to homogeneity. RBcel1 displayed an endoglucanase activity, producing cellobiose and cellotriose, using carboxymethyl cellulose as a substrate. Moreover, the study of pH and the thermal dependence of the hydrolytic activity shows that RBcel1 was active from pH 6 to pH 9 and remained significantly active when temperature decreased (18% of activity at 10 degrees C). It is interesting that RBcel1 was able to synthetize non-reticulated cellulose using cellobiose as a substrate. Moreover, by a combination of bioinformatics and enzyme analysis, the physiological relevance of the RBcel1 protein and its mesophilic homologous Pst_2494 protein from P. stutzeri, A1501, was established as the key enzymes involved in the production of cellulose by bacteria. In addition, RBcel1 and Pst_2494 are the two primary enzymes belonging to the GH5 family involved in this process.The ISME Journal advance online publication, 21 May 2009; doi:10.1038/ismej.2009.48. [less ▲]

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See detailA novel extended-spectrum TEM-type beta-lactamase, TEM-138, from Salmonella enterica serovar Infantis.
chouchani, chedli; Berlemont, Renaud ULg; masmoudi, A. et al

in Antimicrobial Agents and Chemotherapy (2006), 50(9), 3183-5

A novel natural TEM beta-lactamase with extended-spectrum activity, TEM-138, was identified in a ceftazidime-resistant clinical isolate of Salmonella enterica serovar Infantis. Compared to TEM-1, TEM-138 ... [more ▼]

A novel natural TEM beta-lactamase with extended-spectrum activity, TEM-138, was identified in a ceftazidime-resistant clinical isolate of Salmonella enterica serovar Infantis. Compared to TEM-1, TEM-138 contains the following mutations: E104K, N175I, and G238S. The bla(TEM-138) gene was located on a 50-kb transferable plasmid. Expression studies with Escherichia coli revealed efficient ceftazidimase and cefotaximase activities for TEM-138. [less ▲]

Detailed reference viewed: 37 (2 ULg)