TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Process: In producing lipids from biomass including at least one polysaccharide, the biomass including at least one polysaccharide is a lignocellulosic biomass. The biomass including at least one polysaccharide is subjected to a preliminary grinding process before being subjected to the acid hydrolysis. The acid hydrolysis is carried out in the presence of at least one inorganic acid. The biomass including at least one polysaccharide or the first solid phase are present in the reaction mixture in a quantity ranging from 5% by weight to 20% by weight with respect to the total weight of the reaction mixture. The inorganic acid is selected from: sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, or mixtures. The inorganic acid is present in the aqueous solution at a concentration ranging from 0.1% by weight to 2% by weight with respect to the total weight of the aqueous solution. The acid hydrolysis is carried out at a temperature ranging from 140 degrees C to 270 degrees C. The acid hydrolysis is carried out for a time ranging from 10 seconds to 30 minutes. The first aqueous phase and/or the second aqueous phase are subjected to a treatment with at least one adsorbing material obtaining a third aqueous phase and/or a fourth aqueous phase, respectively. Before being fed to the fermentation device, or before being subjected to the treatment with at least one adsorbing material, the first aqueous phase and/or the second aqueous phase are subjected to neutralization by the addition of at least one oxide and/or of at least one hydroxide, such as calcium oxide, calcium hydroxide or barium hydroxide, or mixtures. The treatment with at least one adsorbing material is carried out at a temperature ranging from 10 degrees C to 150 degrees C. The treatment with at least one adsorbing material is carried out at a pressure ranging from 0.5 bar to 10 bar. The treatment with at least one adsorbing material is carried out for a time ranging from 10 minutes to 6 hours. The adsorbing material is selected from crystalline microporous silicates or metal silicates of the zeolite type having MFI, MOR, FAU or BEA structures. The adsorbing material is added to the first aqueous phase and/or to the second aqueous phase in a quantity ranging from 0.5% by weight to 50% by weight with respect to the total weight of the first aqueous phase or of the second aqueous phase. The fermentation is carried out at a temperature ranging from 20 degrees C to 40 degrees C. The fermentation is carried out for a time ranging from 2 days to 10 days. The fermentation is carried out at a pH ranging from 4.5 to 7. The oleaginous yeast can be selected from: Rhodotorula glutinis, Rhodotorula gracilis, Rhodotorula graminis, Lypomices starkeyi, Lypomices lipofer, Trigonopsis variabilis, Candida kefyr, Candida curvata, Candida lipolytica, Torulopsis sp., Pichia stipitis. The microfiltration is carried out by means of membranes based on regenerated cellulose, or by means of ceramic membranes. The process comprises adding corn steep liquor to the fermentation device in a quantity ranging from 2-20 g/L. The process comprises subjecting the second oleaginous cellular biomass including lipids to thermal treatment, where the thermal treatment is carried out at a pressure ranging from 2 bar to 6.5 bar. The thermal treatment is carried out at a temperature ranging from 100 degrees C to 160 degrees C. The thermal treatment is carried out for a time ranging from 1-8 hours. At the end of the thermal treatment the oleaginous cellular biomass is subjected to extraction, in the presence of at least one organic solvent, such as ethyl acetate. EXAMPLE - No suitable example given.