• Reduce text

    Reduce text
  • Restore text size

    Restore text size
  • Increase the text

    Increase the text
  • Print

Rangées de graines.. © INRA, Elena Schweitzer © Fotolia

Our results

  1. Introduction
  2. Research and Innovation 2018 - For Food and Biobased Products
  3. Dry-cured ham: a process simulator can now define routes of manufacture that yield lower-salt products
  4. The way in which proteins aggregate when heated may change their sensitising potency
  5. Enhancing the viability of spray-dried probiotic bacteria by stimulating their stress tolerance
  6. Human milk digestion in the preterm infant: impact of technological treatments
  7. Research & Innovation 2017 - For Food and Biobased Products
  8. To stick or not to stick? Pulling pili sheds new light on biofilm formation
  9. When biopolymers selfassemble: a balance between energy and entropy.
  10. Mimicking the gastrointestinal digestion in a lab-on-a-chip:the microdigester
  11. How a milk droplet becomes a powder grain
  12. Research & Innovation 2016 - For Food and Bioproducts
  13. A new process for the biorefining of plants
  14. Under the UV light : the bacterial membrane
  15. Reverse engineering or how to rebuild ... bread!
  16. Green Chemistry: a step towards lipid production in yeast
  17. Individually designed neo-enzymes for antibacterial vaccines
  18. Multi-scale mechanical modelling: from the nanometric scale to the macroscopic properties of bread crumb
  19. Minimill: 500 g to assess the milling value of soft wheats
  20. Microbial production of lipids for energy or chemical purposes
  21. The discrete role of ferulic acid in the assembly of lignified cell wall
  22. Eco-design of composites made from wood co-products
  23. Analysis of volatile compounds enables the authentication of a poultry production system
  24. Nanoparticles as capping agents for biopolymers microscopy
  25. Pasteurisation, UHT, microfiltration...All the processes don't affect the nutritional quality of milk in the same way
  26. Integration of expert knowledge applied to cheese ripening
  27. Controlling cheese mass loss during ripening
  28. The shape memory of starch
  29. Research & Innovation 2015 - For Food & Biobased Products
  30. Behaviour of casein micelles during milk filtering operations
  31. Overaccumulation of lipids by the yeast S. cerevisiae for the production of biokerosine
  32. Sequential ventilation in cheese ripening rooms: 50% electrical energy savings
  33. An innovative process to extract bioactive compounds from wheat
  34. Diffusion weighted MRI: a generic tool for the microimaging of lipids in food matrices
  35. Characterization of a major gene of anthocyanin biosynthesis in grape berry
  36. New enzyme activity detectors made from semi-reflective biopolymer nanolayers
  37. Improving our knowledge about the structure of the casein micelle
  38. Heating milk seems to favour the development of allergy in infants
  39. Fun with Shape
  40. Using volatile metabolites in meat products to detect livestock contamination by environmental micropollutants
  41. SensinMouth, when taste makes sense
  42. A decision support system for the fresh fruit and vegetable chain based on a knowledge engineering approach
  43. SOLEIL casts light on the 3D structure of proteins responsible for the stabilisation of storage lipids in oilseed plants
  44. A close-up view of the multi-scale protein assembly process
  45. Controlling the drying of infant dairy products by taking water-constituent interactions into account
  46. Polysccharide nanocrystals to stabilise pickering emulsions
  47. Discovery of new degradative enzymes of plant polysaccharides in the human intestinal microbiome
  48. A durum wheat flour adapted for the production of traditional baguettes
  49. Virtual modelling to guide the construction of « tailored-made » enzymes
  50. How far can we reduce the salt content of cooked meat products?
  51. Diffusion of organic substances in polymer materials: beyond existing scaling laws
  52. Smart Foams : various ways to destroy foams on demand !
  53. Dates, rich in tannins and yet neither bitter nor astringent
  54. Sodium content reduction in food
  55. Research & Innovation 2014

Discovery of new degradative enzymes of plant polysaccharides in the human intestinal microbiome

Microorganisms play a vital role in the carbon cycle, in particular, by contributing to plant degradation via a perfectly adapted enzymatic apparatus. However, a major obstacle stands in the way of taking advantage of this remarkable enzyme reservoir. In fact, it is estimated that over 95% of the microorganisms present in a large number of ecosystems have never been cultivated and are therefore unknown.

Synthesis pictures illustrating the discovery of new enzyme by functional metagenomy. © inra, Gabrielle VERONESE

Investigating complex ecosystems such as the human intestine

Within this framework, the metagenomic potential is enormous.  This technology, also known as "community genomics", corresponds to the analysis of genomes of all the organisms within a given ecological niche, without any cultivation step.  It has been used in recent years to investigate how complex ecosystems, such as that of the human intestine, function.  Intestinal bacteria play a major role in the maintenance of human health and contribute to nutrition via the metabolisation of undigested food fractions in the upper part of the digestive tract, especially dietary fibres consisting of plant polysaccharides.

Researchers have recently developed a powerful strategy for streamlining metagenome sequencing in order to accelerate the discovery of new enzymes.  This approach was applied to the exploration of the human intestinal metagenome to more effectively understand how bacteria in the digestive tract degrade the plant polysaccharides.

Identifying enzymes with great fiber degradation potential

High-throughtput functional screening of a library of recombinant clones containing fragments of metagenomic DNA, operating at a rate of 200,000 clones per week, made it possible to explore the huge diversity of this ecosystem.  Several hundred clones capable of degrading starch, cellulose, hemicelluloses, pectins and galactan were isolated.  These clones were then submitted to a secondary screening to access their effectiveness for degrading recalcitrant substrates and their stability, in order to isolate the enzymes with the greatest plant biomass degradation potential.  Sequencing efforts were concentrated on 0.84 Mb of metagenomic DNA, corresponding to the 26 most interesting clones.  As a result, 73 polysaccharide degradative enzymes were identified, several of which belonging to new families that have never been characterised.  New multigene systems coding for complementary activities necessary for the deconstruction of complex structures of the plant cell wall were also revealed.

The results allow us to more effectively understand how food fibres are metabolised and with which bacteria, and illustrate the strength of this generic approach for the valorization of the functional diversity of metagenomes.  

Evaluating the effectiveness of these new enzymes to degrade plant biomass

A dual challenge exists in terms of the development of these metagenomic data.  From a generic point of view, we must improve our knowledge of structure-function relationships of these newly identified enzymes at the atomic scale.  From a finalised point of view, the research will initially focus on the effectiveness of these enzymes, alone or in cocktails, to degrade plant biomass.  On the long-term, the aim is to develop a synthetic biology approach based on systems naturally developed by bacteria to adapt to the deconstruction of complex polysaccharide structures.


  • PhD from the Ministry of Research


  • AFMB (CNRS Marseille) : B. Cantarel, P. Coutinho, B. Henrissat
  • Micalis (INRA de Jouy-en-Josas) : J. Tap, M. Leclerc, J. Doré
  • Plateforme BioInformatique Genotoul (INRA Toulouse) : C. Klopp
  • LibraGen SA (Toulouse) : P. Robe, R. Nalin


See also

  • Tasse, L., J. Bercovici, S. Pizzut-Serin, P. Robe, J. Tap, C. Klopp, B.L. Cantarel, P.M. Coutinho, B. Henrissat, M. Leclerc, J. Doré, P. Monsan, M. Remaud-Simeon, and G. Potocki-Veronese. 2010. Functional metagenomics to mine the human gut microbiome for dietary fiber catabolic enzymes. Genome Research 20: 1605-1612.