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

Our results

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

Overaccumulation of lipids by the yeast <i>S. cerevisiae</i> for the production of biokerosine

Oils derived from the biomass for use as energy are a realistic alternative today to fossil fuels derived from petroleum. Two sources are being explored:

- That of vegetable oils (rapeseed and sunflower oils), already well established

- That of oils produced from microorganisms (algae and yeasts), that is currently making rapid strides

In cells, oils are stored into lipid bodies. These structures carry on their surface proteins that have an original structure capable of stabilising lipids in an aqueous environment. Thanks to the heterologous expression of one of these proteins, caleosin (AtClo1), found in the seed of Arabidopsis thaliana, researchers have demonstrated its ability to promote the proliferation of lipid bodies in the yeast, Saccharomyces cerevisiae, thus obtaining an increase of 46.6% of the fatty acid content. Research is continuing using this modified strain to develop high-yield biological oil production systems. Projects in progress aim at positioning yeasts as an alternative pathway for the production of biofuels for aeronautic use.

Keywords:

Exploring the potential of plants to obtain oils to produce energy

Within the current context of fossil resource rarefaction, rising oil prices and protection of the environment, the conversion of energy from oils derived from the biomass and green chemistry have become increasingly important.  In fact, oils derived from the biomass and their biodegradable by-products have become a viable option to replace products made from fossil oil.  They are more and more prevalent in manufactured products (soap, cleaning products) and in industrial products (solvents, lubricants, printing inks).  Two sources are being considered: that of vegetable oils (rapeseed or sunflower), already well established, and that of oils produced from microorganisms (algae and yeasts), currently on the upswing.  
Research being carried out within the team, "Dynamics and structure of lipid bodies", is on this theme and aims at identifying the factors that influence the quality and quantity of original and interesting lipids produced through plant breeding orthe genetic transformation of yeast.  Our projects on yeasts as an alternative to biofuel production for aeronautic applications is supported by the French National Research Programme on Bioenergies and the French Civil Aviation Administration.  

   A model plant and baker's yeast

In cells, storage lipids are packaged into specialised structures called lipid bodies  These lipid droplets are present in higher eukaryotes, in plant seeds (where they are referred to as oleosomes and contain oils), and in some microorganisms such as yeasts.  Proteomic approaches conducted on lipid bodies made it possible to identify proteins associated with this compartment, which then appeared as a dynamic organelle contributing to the control of metabolism and cellular signalisation, rather than an inert fat deposit.
Caleosin (AtClo1) is a minor protein present at the surface of lipid bodies in the seeds of Arabidopsis thaliana. Like oleosins,the major proteins found in lipid bodies, AtClo1 shares a triblock structure, which allows its insertion at the surface of these organelles. It also possesses a functional calcium binding site.  The study of plants deficient in caleosin revealed the implication of this protein in the degradation of lipids during germination. The role of this protein on lipid storage is still unknown. Using a system of heterologous expression, we were able to demonstrate the capacity of this plant protein to induce the proliferation of lipid bodies and to modify lipid storage in baker's yeast (Saccharomyces cerevisiae).

Increasing the oil content of S. cerevisiae

The yeast Saccharomyces cerevisiae generally includes several small-size lipid bodies (approximately 200 nm in diameter).  We expressed caleosin (AtClo1) associated with a fluorescent protein in this model unicellular eukaryote.  We studied the impact of the expression of this protein on the structure of lipid bodies and the oil content of cells.  We were able to demonstrate an increase in the number and diameter of lipid bodies (Fig. 1) that led to an increase of 46.6% of fatty acid content (compared to a non-modified strain).  These results show that caleosin has physico-chemical properties that allow it to promote the genesis of a membrane capable of packaging lipids and therefore leading to an increase in oil content in the yeast.
 

Figure 1 : L'expression de la protéine de fusion AtCLO1-GFP induit une prolifération des corps lipidiques (structures rondes et blanches sur les photos obtenues en microscopie électronique à transmission) chez la levure de boulangerie.. © INRA
Figure 1 : L'expression de la protéine de fusion AtCLO1-GFP induit une prolifération des corps lipidiques (structures rondes et blanches sur les photos obtenues en microscopie électronique à transmission) chez la levure de boulangerie. © INRA

Figure 1: The expression of the fusion protein AtCLO1-GFP induces a proliferation of lipid bodies (round, white structures on the photos obtained with transmission electron microscopy) in baker's yeast.

A new tool for studying the development of biological systems to produce oils

Our results show that the heterologous expression of AtClo1, a protein found in the oleosomes of the model plant A. thaliana, induces an over-accumulation of lipids in the yeast S. cerevisiae.  It is actually possible to considerably increase the lipid content of the widely used and popular baker's yeast by "vegetalising" its lipid bodies through the expression of an A. thaliana protein. Since this protein is not an enzyme of the lipid biosynthesis pathway, the mechanisms leading to the proliferation of lipid bodies and the accumulation of lipids are still unknown and could therefore involve carbon flow balance or metabolic control upstream of the lipid biosynthesis pathway. This the reason why this research is focusing on this modified strain with the potential to become an extraordinary tool for the understanding of lipid body dynamics and the development of successful biological systems for oil production. 

Partners

  • Equipe Ubiquitine et trafic intracellulaire, Institut Jacques Monod, CNRS et Université Paris Diderot, Bat.Buffon, 15 rue Hélène Brion 75205 Paris Cedex 13, France
  • Equipe Développement et qualité des graines, Institut Jean-Pierre Bourgin, INRA AgroParisTech, Centre de Versailles-Grignon, Route de St-Cyr (RD10), 78026 Versailles Cedex France
  • Equipe Génie Microbiologique, Laboratoire Ingénierie des Systèmes Biologiques et Procèdes, INSA CNRS et INRA, 135 avenue de Rangueil, 31077 Toulouse Cedex France
  • Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette Cedex, France

See also

  • Microbial production of lipids for energy or chemical purposes
  • Froissard, M., D'Andréa, S., Boulard, C., Chardot, T. (2009). "Heterologous expression of AtClo1, a plant oil body protein, induces lipid accumulation in yeast." FEMS Yeast Res 9(3): 428-38.
  • An other strategy of lipids bodies proliferation: Microbial production of lipids for energy or chemical purposes