• Aucun résultat trouvé

Selection and cultivation of hydrolytic microorganisms extracted from the digestive tract of the termite Reticulitermes santonensis (3DV.1.55)

N/A
N/A
Protected

Academic year: 2021

Partager "Selection and cultivation of hydrolytic microorganisms extracted from the digestive tract of the termite Reticulitermes santonensis (3DV.1.55)"

Copied!
1
0
0

Texte intégral

(1)

Selection and cultivation of hydrolytic microorganisms extracted from

the digestive tract of the termite Reticulitermes santonensis (3DV.1.55)

Biofuel production can be based on the use of fermentable substrates issued from the hydrolysis of lignocellulosic biomass coming from agricultural residues and by-products. However, such substrates are not easy to degrade. Enzymes (cellulases, xylanases, etc.) can be used for this purpose and pre-treatments can increase their action by providing more available extremities. The digestive tract of the termite Reticulitermes santonensis contains various microorganisms (bacteria, molds, protists) able to degrade the wood components. These microorganisms act as consortia, leading to a better hydrolysis than in the cow rumen. It was possible to isolate such microorganisms from termite guts in order to evaluate their potential for hydrolysis of lignocellulosic materials. This approach led to the isolation of three microorganisms : Bacillus subtilis, displaying a xylanase activity, Aspergillus

fumigatus, displaying a cellulase activity and a protist (related to the chrysophytes Ochromonas and Poterioochromonas) displaying an amylase activity.

INTRODUCTION

O2

LIGNOCELLULOSE DEGRADATION IN LOWER

TERMITES

ISOLATION OF ENZYME-PRODUCING

MICROORGANISMS

DISCUSSION

Tarayre Cédric1, Bauwens Julien2, Mattéotti Christel3, Brasseur Catherine4, Destain Jacqueline1,

Vandenbol Micheline3, Portetelle Daniel3, De Pauw Edwin4, Haubruge Eric2, Francis Frédéric2 and

Thonart Philippe1

1 - Bio-Industries unit – University of Liege Gembloux Agro-Bio Tech

2 - Functional and evolutionary entomology unit – University of Liege Gembloux Agro-Bio Tech 3 - Animal and microbial biology unit – University of Liege Gembloux Agro-Bio Tech

4 - Mass spectrometry laboratory – University of Liege

Head Foregut Midgut Hindgut Faeces

Microoxic zone Anoxic zone Bacteria Molds Symbiotic protists Cellulose H2, CO2 CH4 Acetate Short chain fatty acids Mono-, di- and oligosaccharides Organic acids HINDGUT FOREGUT MIDGUT Dissection Liquid medium containing starch and ciprofloxacin

Agar plates containing cellulose, carboxymethylcellulose or cellobiose (microaerobic or

anaerobic atmosphere)

Tryptic soy broth

SCREENING OF ENZYMATIC ACTIVITIES

Isolation of one protist

Isolation of bacteria and

molds

Selection of hydrolytic microorganisms

Bacillus subtilis Aspergillus fumigatus Chrysophyte related to Ochromonas and Poterioochromonas

Positive control Positive control Positive control

Culture

samples samplesCulture Culturesamples Neg.

control controlNeg. controlNeg.

Detection of a xylanase activity Detection of an amylase activity Detection of a cellulase activity

DISCUSSION

ENZYME PRODUCTION

Termite dissections led to the isolation of three hydrolytic microorganisms until now. The most interesting microorganism is

Bacillus subtilis, producing an extracellular enzyme able to degrade

xylans. Bacillus subtilis was able to develop a xylanase activity up to 15 I.U. (International Units)/mL. It was able to develop such activity in a liquid medium containing rape oil cake. Other microorganisms will also be tested.

Optimization of enzyme production : measurement

of enzymatic activities of

Références

Documents relatifs

The traits measured were body weight (BW), feed conversion ratio (FCR), AMEn, weights of crop, liver, gizzard and proventriculus, and weight, length and density of the duodenum,

Use the Comparison Test to determine which of the following series are convergent and which are divergent. Find € lim n→∞

Keywords: Tetraclinis articulata, heartwood, wood extractives, essential oil, methanolic extracts, termites, Basidiomycetes fungi, antitermitic..

E n temps de crise et de pénurie budgétaire, des choix judicieux doivent être faits pour l’éla- boration de la politique des soins de santé, non seulement en Bel- gique, mais

Si la première étape s’est basée sur les matrices individuelles, cette étape trouvera dans la matrice collective les informations néces- saires. Elaboration

obesity, its nutritional consequences and complications, and opens discussion on the possible impact of bariatric surgery on weight loss, nutritional deficiencies, response

charge carriers recombination probability increases with thickness. By contrast, photoactive materials have to be thick enough to ensure light absorption leading to the formation of

La première ligne permet d’expliciter la tâche : il faut dessiner autant de doigts (comme Patti) et de points (comme Dédé) qu’il y a de jetons dans la boite de Picbille. En