Integrated process for the production of bio-oil from micro-organisms

An integrated process for producing a bio-oil from a phototrophic micro-organism and a heterotrophic micro-organism, the process comprising:

• a. growing at least one phototrophic microalga, in a dedicated first pond or container comprising water, nutrients, and a device adapted to distribute carbon dioxide in the water, to obtain a developed phototrophic biomass;
• b. growing at least one heterotrophic microalga, optionally in consortium with other microorganisms, in a dedicated second pond or container comprising water and nutrients, to obtain a developed heterotrophic biomass, wherein the growing is performed in the presence of carbohydrates and/or proteins transported by a suspension coming from a hydrothermal treatment of a biomass;
• c. recovering the developed phototrophic biomass and the developed heterotrophic biomass, with their growth water, as a global suspension, and thickening the global suspension at least up to 5% by weight, in a dedicated thickening section;
• d. thermally treating the thickened global suspension, at a temperature in the range of 80 to 350° C. and a pressure in the range of 0.1 to 25 MPa, for at least one minute, to obtain a thermally treated thickened suspension;
• e. recovering, after cooling the thermally treated thickened suspension, an oil fraction adapted to be transformed into a bio-fuel;
• and
• f. supplying a resulting aqueous suspension, rich in carbohydrates and proteins, assimilable by the heterotrophic microalgae, to (b).