The present invention relates to a microorganism belonging to the microalgal species tetraselmis mediterranean tmmru sp. (bea/ida/0062) and the use of said strain to increase the isotope ratio235 u/ 238 u of a solution with respect to a starting solution containing residual uranium with a relation235 u/ 238 u minor, as well as the procedure to obtain said solution more enriched in235 u. (Machine-translation by Google Translate, not legally binding)
1. A micro-algae microorganism Tetraselmis mediterranea TmmRU with Spanish Algae Bank identification number BEA/IDA/0062. 2. Use of the microorganism, according to claim 1, in a method for the production of a uranium solution with a ratio <235>U/<238>U enriched in <235>U in relation to a starting solution, i.e. a uranium solution containing a ratio <235>U/<238>U greater than the ratio <235>U/<238>U in the starting solution. 3. Use, according to claim 2, for the production of a solution with an isotopic ratio <235>U/<238>U of 0.7%. 4. A method for the production of a solution enriched in <235>U with respect to the starting solution comprising the following stages: a. Culturing the microorganism, according to claim 1, in a uranium medium also containing an adequate culture medium and under temperature conditions between 18-28°C and light conditions between 60-100 µmol photons/m<2>s b. Separating the algal biomass obtained according to step a. by means of a centrifugation or filtration stage. c. Obtaining a solution enriched in <235>U with respect to the starting solution from the algal biomass obtained in stage b. by means of an acid digestion process. 5. The method, according to the preceding claims, characterized in that the uranium solution of stage a has an isotopic ratio <235>U/<238>U of 0.2%. 6. The method, according to the preceding claims, characterized in that the size of the inoculum of the alga Tetraselmis mediterranea TmmR used in stage a ranges between 50,000 cells/ml-150,000 cells/ml. 7. The method, according to the preceding claims, characterized in that the size of the inoculum of the alga Tetraselmis mediterranea TmmRU used in stage a is 100,000 cells/ml. 8. The method, according to the preceding claims, characterized in that the culture medium is f/2 medium. 9. The method, according to the preceding claims, characterized in that the temperature and light conditions of stage a are carried out at 22°C and 80 µmol photons/m<2>s. 10. The method, according to claim 4, characterized in that the centrifugation of stage b is carried out at 3,500 r.p.m. for 10 minutes. 11. The method, according to claim 4, characterized in the filtration of stage b. is carried out under vacuum conditions using a filter with a pore size of 22 µm. 12. The method, according to claim 4, characterized in that the digestion of stage c is carried out in two stages: a drying stage up to a constant weight followed by treatment with 2% v/v nitric acid.