Identification of Highly Active Flocculant Proteins in Bovine Blood

Abstract

Synthetic polymeric flocculants are used extensively for wastewater remediation, soil stabilization, and reduction in water leakage from unlined canals. Sources of highly active, inexpensive, renewable flocculants are needed to replace synthetic flocculants. High kaolin flocculant activity was documented for bovine blood (BB) and blood plasma with several anticoagulant treatments. BB serum also had high flocculant activity. To address the hypothesis that some blood proteins have strong flocculating activity, the BB proteins were separated by SEC. Then, the major proteins of the flocculant-active fractions were separated by SDS-PAGE. Identity of the major protein components was determined by tryptic digestion and peptide analysis by MALDI TOF MS. The sequence of selected peptides was confirmed using TOF/TOF-MS/MS fragmentation. Hemoglobin dimer (subunits α and β) was identified as the major protein component of the active fraction in BB; its high flocculation activity was confirmed by testing a commercial sample of hemoglobin. In the same manner, three proteins from blood plasma (fibrinogen, γ-globulin, α-2-macroglobulin) were found to be highly active flocculants, but bovine serum albumin, α-globulin, and β-globulin were not flocculants. On a mass basis, hemoglobin, γ-globulin, α-2-macroglobulin were as effective as anionic polyacrylamide (PAM), a widely used synthetic flocculant. The blood proteins acted faster than PAM, and unlike PAM, the blood proteins flocculants did not require calcium salts for their activity.

Valorization of rendering industry wastes and co-products for industrial chemicals, materials and energy: review

“…The flocculation potential of meat and bone meal extract and gelatin (Piazza & Garcia, 2010a), chicken blood extract (Piazza et al, 2011), bovine blood extract (Piazza et al, 2012), hydrolyzed meat and bone meal extract (Piazza & Garcia, 2010b;Piazza & Garcia, 2013) has been investigated and reported in the literature. Similar to other renewable feedstocks, modification of protein is essential to enhance its flocculation capability.…”

Flocculation of kaolin and lignin by bovine blood and hemoglobin

“…18 Flocculant testing of individual bovine blood (BB) proteins showed that several proteins, including hemoglobin (HEM), were flocculants of kaolin. 19 Detailed studies on the kaolin and wheat straw soda lignin flocculant activities of BB and HEM are reported here.…”

Flocculation of wheat straw soda lignin by hemoglobin and chicken blood: effects of cationic polymer or calcium chloride

“…The change in the observed FTIR spectra of the HEM–lignin composite in response to increased levels of CaCl 2 demonstrates that Ca +2 is promoting a change within the HEM molecules which correlates with improved lignin flocculation. The amide I band (1653 cm −1 ) of a protein is the most sensitive spectral region in the protein environment and protein secondary structure, and therefore the changes in the intensity of this band with the addition of CaCl 2 show that CaCl 2 is influencing HEM. Also it is noted that the addition of NaCl to HEM–lignin produced no change in the intensity of the amide I band of HEM.…”

“…It was previously shown that whole blood is an effective flocculant of kaolin. 25 The most abundant protein in blood is HEM, and chicken blood (CB) may be considered a crude form of HEM. The influence of CB on the flocculation of lignin is shown in Fig.…”