Submitted to: Waste to Worth Conference
Publication Type: Proceedings
Publication Acceptance Date: 3/10/2017
Publication Date: 3/19/2017
Citation: Vanotti, M.B., Szogi, A.A., Brigman Jr, P.W. 2017. Recovery of proteins and phosphorus from manure. In: Proceedings of Waste to Worth Conference, April 19-20, 2017, Raleigh, North Carolina.
Technical Abstract: The recovery of phosphorus and proteins from manure could be advantageous to both offset costs and to improve and lessen the environmental impacts of manure storage and treatment. Phosphorous in manure can contaminate rivers, lakes, and bays through runoff, if applied onto a cropland excessively. Thus, recovering phosphorous from manure can not only help reduce such runoffs, but also reduces the use of commercial fertilizer based on phosphate rock. The phosphorus mine has limited reserves and cannot be replaced by other means as fertilizer. Protein is a natural resource used in a wide range of commercial applications from pharmaceuticals to dietary supplements, foods, feeds, and industrial applications. A new method for simultaneous extraction of proteins and phosphorus from biological materials has been developed and is presented. The experiments used swine manure solids fraction after solids-liquid separation. From raw manure, wet solids are dissolved in acidic solution and then treated with a basic solution so phosphorus will precipitate and be reclaimed. The proteins in the washed solids can be extracted and concentrated with ultrafiltration and flocculation. On a dry-weight basis, it was found that the separated manure solids contained 15.2-17.4% proteins and 3.0% phosphorus. Quantitative extraction of phosphorus and proteins from manures was possible with this new system. The phosphorus was first separated from the solids in a soluble extract, then the proteins were separated from the solids and solubilized with an alkali solvent. Both phosphorus and protein recovery were enhanced about 19 and 22% with the inclusion of a rinse after the washing. The recovered phosphorus solids had 20.4% phosphates (P2O5). The protein extract was concentrated using ultrafiltration (UF) and lyophilization to obtain a protein solids concentrate. UF of 5 and 10 kDa captured all the proteins, but 30 kDa resulted in 22% loss. The protein solids were converted into amino-acids using acid hydrolysis Further, the system was proved effective to extract phosphorus and proteins from other biological materials, such as algae or crops. The recovered proteins could be used for production of amino acids and the recovered phosphorus could be used as a recycled material that replaces commercial phosphate fertilizers. This could be a potential new revenue stream from wastes.