NOVELTY - The process comprises subjecting a municipal solid waste to liquefaction obtaining a mixture including an oily phase consisting of bio-oil, a solid phase and a first aqueous phase, subjecting the first aqueous phase to a treatment with an adsorbing material obtaining a second aqueous phase, subjecting the second aqueous phase with the adsorbing material to fermentation obtaining a biomass, and subjecting the biomass. The municipal solid waste before subjected to the liquefaction step is treated by preliminary grinding or sizing process.    USE - The process is useful for producing bio-oil from a municipal solid waste such as primary and biological sludge produced in wastewater purification plants, residues and/or scraps deriving from: agricultural and/or zootechnic activities; a agro-food industry; and agricultural processing, forestation and/or silviculture, organic material from sorted waste collection or mixtures of the organic material with pruning cuttings and/or agricultural residues (all claimed), where the bio oil is useful in the production of biofuels for motor vehicles, and is useful as fossil combustibles for generation of electric energy or heat.    ADVANTAGE - The process is capable of economically producing the bio-oil from a wet municipal solid waste, and allows a good yield of bio-oil even under milder temperature and pressure conditions.    DETAILED DESCRIPTION - The process comprises subjecting a municipal solid waste to liquefaction obtaining a mixture including an oily phase consisting of bio-oil, a solid phase and a first aqueous phase, subjecting the first aqueous phase to a treatment with an adsorbing material obtaining a second aqueous phase, subjecting the second aqueous phase with the adsorbing material to fermentation obtaining a biomass, and subjecting the biomass. The municipal solid waste before subjected to the liquefaction step is treated by preliminary grinding or sizing process. The municipal solid waste has a water content of 55-80 wt.%. The step of liquefaction is carried out: at a temperature of 200-320 degrees C; at a pressure of 15-115 bar; and for a time of 15-90 minutes. The oily phase, the solid phase, and the first aqueous phase included in the mixture are separated by gravitational separation, filtration, centrifugation. The step of treatment with the adsorbing material is carried out: at a temperature of 30-100 degrees C; at a pressure of 1-2 bar; and for a time of 30 minutes to 4 hours. The adsorbing material is added to the first aqueous phase in an amount of 5-15wt.%. The step of fermentation is carried out: in the presence of one oleaginous yeast and one microbial consortium isolated from the first aqueous phase or from the second aqueous phase with the adsorbing material; at a temperature of 25-35 degrees C; at a pH of 5-7; and for a time of 24-100 hours. The oleaginous yeast is rhodotorula glutinis, rhodotorula gracilis, rhodotorula graminis, lypomices starkeyi, lypomices lipofer, trigonopsis variabilis, candida kefyr, candida curvata, candida lipolytica, torulopsis sp., pichia stipitis, criptococcus albidus, and/or criptococcus sp.. The biomass is subjected to a thickening process at the end of the fermentation step before subjected to the liquefaction step. An INDEPENDENT CLAIM is included for bio-oil.    DESCRIPTION OF DRAWING(S) - The figure shows a flow chart of process of producing bio-oil from a municipal solid waste.