Phosphorus is found in many organic residues as both inorganic and organic compounds. These phosphorus compounds may be very stable in nature. The phosphorus dosage can therefore hardly be controlled by direct application of manure or fermentation residues. This frequently results in an over-application of phosphorus on soil, which has negative environmental and economic consequences. The natural biological decomposition process converts these organic compounds into inorganic plantavailable ions (NO3–, NH4+, PO43–). However, this process can take several months or years, as it depends on the specific local conditions such as humidity, temperature, precipitation, the activity of microorganisms, etc. At the Fraunhofer IGB, we have developed analytical methods for the characterization of organic residues in regard to their phosphorus content. Moreover, we are developing biocatalytic processes for the mineralization of organic phosphorus in agricultural residues and its recovery as a valuable fertilizer.