NOVELTY - Decomposition of natural structure of biomass containing lignin and solubilization of lignin and other components comprises solubilizing and degrading solubilized components to fragments having molecular weight below 1000 g/mol in continuous reactor at elevated temperature and elevated pressure using lactic acid, lactic acid oligomer or their aqueous solution.    USE - Decomposition of natural structure of biomass containing lignin and solubilization of lignin and other components for producing degraded biomass, solubilized components and smaller molecular weight compounds used as biofuels, liquid fuel, feed material in fermentation plant or biorefinery, component in chemical products, monomer in polymerization, component in resins, additive, and component or crude material of biofuels, liquid fuel or chemical products (claimed). The method is also used for exploitation, separation, molecular fragmentation and/or recovery of straw biomass, peat, betulin, hemicellulose, lignin, lignanes, phenolic compounds and saccharides.    ADVANTAGE - The method allows continuous production of great amounts of lignin and other components in fibrous biomass, and especially degradation compounds having lower molecular weight, and located into lactic acid containing liquid phase. Excessive coke formation which reduces yield and leads to fouling and plugging of equipment is avoided, and the reaction liquid remains in liquid phase and easily flows throughout the entire process. The method enables batchwise or continuous process that degrades large quantities of biomass and/or its components into molecules of lower molecular weights. The components of solubilized lignin fragments molecules from biomass can be decomposed with good yield and without harmful side reactions to form compounds having molecular weight even below 1000 g/mol. The use of lactic acid to degrade structure of biomass and solubilize does not require the use of sulfur-containing compounds.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for use of a degradation equipment in performing decomposition of natural structure of biomass containing lignin and solubilization of lignin and other components in a way that the biomass and its fragments including lignin and other components degrade to fragments having molecular weight level below 1000 g/mol. The degradation equipment comprises pressure pump (2) for feed flow, which is piston pump or gear pump; reactor with temperature regulator (4), which is pipe reactor without gas phase and which can be heated; heat exchanger (8) and pressure reducing valve (6).    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of a degradation equipment.    Pressure pump (2)    Pressure indicator (3)    Temperature regulator (4)    Pressure reducing valve (6)    Heat exchanger (8)