The present invention comprises a method for culturing genetically modified cells of Ustilago mayds el fungus, where, by means of the invention, the fungus secrets a gum formed by polysaccharide B-D (1-3) glucan to the medium with emulsifying properties and which is treated in such a manner that this may be used as additive in food, pharmaceutical and cosmetic products, amongst others. The gum is produced by stains of Ustilago maydis fungus, which has been genetically modified in different points of a metabolic path that regulates the response to environmental pH under particular conditions of pH and uses different sources of carbon from simple such as glucose to complex such as xylan or cellulose. One of these strains, particularly (FMA2) has been modified in such a manner that it is unable to be paired and therefore unable to generate infections in maize plants. This gum may be used as an emulsifying agent, as an emulsion stabilizer and as thickener agent. It is also used as a textu re modifier in the food industry and as a carrier or a biodegradable edible cover in the pharmaceutical industry, without discarding further applications.La presente invención comprende un metodo de cultivo de células modificadas genéticamente del hongo Ustilago mayds el, mediante la presente invención, secreta una goma compuesta de polisacárido B-D (1-3) glucana al medio con propiedades emulsificantes y que es tratada de tal manera que puede ser usada como aditivo en productos alimenticios como se menciona en el presente documento, farmacéuticos o cosméticos, por mencionar algunos. La goma es producida por cepas del hogo Ustilago maydis que ha sido modificado genéticamente en diferentes puntos de una ruta metabólica que regula la respuesta a pH ambiental en condiciones particulares de pH y utilizando diferentes fuentes de carbono desde simples como la glucosa hasta complejas como xilano o celulosa. Una de estas cepas en particular (FMA2) ha sido modificada de tal manera que es incapaz
