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Title: Proteins and peptides as renewable flocculants

item Piazza, George
item Garcia, Rafael

Submitted to: Bioresource Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2010
Publication Date: 3/17/2010
Citation: Piazza, G.J., Garcia, R.A. 2010. Proteins and peptides as renewable flocculants. Bioresource Technology. 101(15):5759-5766.

Interpretive Summary: Flocculants are used in a wide variety of industrial processes such as wastewater clarification, concentration during chemical operations, and dewatering and thickening in mineral operations. The purpose of this research was to determine if biodegradable agricultural proteins and peptides have potential nonfood use as renewable flocculants to replace polyacrylamide, a widely used flocculant derived from natural gas. Products from abattoir operations such as meat & bone meal, blood meal, and feather meal were treated to prepare protein and peptide fractions. These fractions and other commercial protein preparations were tested for flocculation ability using a procedure that was developed in our laboratory. It was found that some of the proteinaceous fractions were effective flocculants. This research may benefit abattoir operators and protein producers by providing new market opportunities for their products and also increase the use of sustainable technology.

Technical Abstract: Partially hydrolyzed extracts from blood, feather, and meat & bone meals, as well as unhydrolyzed chicken blood and serum, and a variety of common surplus agricultural proteins were tested for their ability to promote the flocculation of clay. Partial alkaline or enzymatic hydrolyses of blood, feather, and meat & bone meals were performed to liberate proteins and peptides from their water-insoluble forms in the meals. Some of these extracts promoted flocculation. However, if hydrolysis was extensive, very low molecular weight peptides were mainly produced, and these extracts did not promote flocculation. Chicken blood and serum, and a beef skin gelatin were found to promote flocculation. Commercial preparations of peptone enzymatic digest, hydrolyzed fish collagen, a mixture of keratin and hydrolyzed keratin, and a lower quality beef gelatin did not promote flocculation.