NOVELTY - Processing manure and/or biomass comprises: (a) fermenting the manure and/or biomass in a first reactor to obtain acidified manure and/or acidified biomass having a pH of below 6, preferably below pH 5.5, preferably below pH 5; (b) separating the acidified manure and/or biomass into a liquid fraction and a solid fraction; and (c) adding the liquid fraction to a second reactor, which second reactor comprises fermenting liquid fraction having a pH of between 6.5 to 8.5, preferably 7.0 to 8.0, and fermenting the thus obtained mixture in the second reactor.    USE - The method is useful for processing manure and/or biomass (claimed).    ADVANTAGE - An advantage of the process is that the acidification of manure in the first reactor results in the formation of complexes comprising of phosphates and naturally-formed fatty acids, in particular volatile fatty acids.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are:    (1) liquid fraction of fermented manure and/or biomass obtainable by the method;    (2) solid fraction of fermented manure and/or biomass obtainable by the method; and    (3) installation for processing of manure and/or biomass comprising a first fermentation reactor, preferably an acidifying reactor, having at least one inlet and at least one outlet, of which an outlet is connected via a suitable conduit to an inlet of a separator for separating acidified manure and/or biomass into a liquid and a solid fraction, the separator having a first outlet for transport of the solid fraction out of the separator and a second outlet for outflow of the liquid fraction, which second outlet is connected via a suitable conduit to an inlet of a second fermentation reactor, preferably a biogas reactor, which second reactor comprises at least one inlet and at least two outlets, where an outlet of the second reactor is for outflow of the liquid fraction out of the second reactor and an outlet of the second reactor is for transport of phosphorus-comprising minerals out of the second reactor, where the rate of outflow through the outlet of the first reactor connected to the separator can be regulated by the pH of the contents of the first reactor, and where the rate of inflow through the inlet of the second reactor connected to the separator for receiving liquid fraction can be regulated by the pH of the contents of the second reactor.