Environmental assessment of phosphorus reduction in rye bran fodder from processing to feeding

An innovative process enables the reduction of phosphorus (P) content in rye bran used as animal fodder. The goal of P extraction is to produce P-reduced feed that lowers P in animal excretion, thereby decreasing eutrophication risks from runoff or leaching into water ecosystems. This article assesses the environmental impacts of both the P extraction process and the use of P-reduced fodder in animal husbandry through a life cycle approach. The analysis includes two stages: (1) environmental assessment of P-reduced bran production via different extraction routes, and (2) assessment of its use as a fodder for pigs. Two extraction routes—thermo-chemical and enzymatic—are evaluated for the “Global Warming” and “Terrestrial Acidification” impacts. The results show that the enzymatic route is characterized by lower values in both impact categories, generating 150 kg CO₂ eq. and 0.2 kg SO₂ eq. compared to 1 863 kg CO₂ eq. and 7.5 kg SO₂ eq. from the thermo-chemical route. In the use stage, the effects of co-feeding pigs with P-reduced bran are analysed for “Global Warming” and “Eutrophication” impacts. P eq. emissions (“Eutrophication”) are reduced by 4%. Yet, the energy-intense processing of P-reduced bran increases the overall greenhouse gas emissions. Feeding untreated bran results in 3 352 kg CO₂ eq. per 1 000 kg carcass weight, while the co-feeding with the P-reduced bran from the thermo-chemical and enzymatic routes leads to 5 672 kg CO₂ eq. and 3 911 kg CO₂ eq., respectively.