title: Decoloring hemoglobin as a feedstock for second-generation bioplastics.
abstract: The color of red blood cell concentrate (RBCC) limits its application in human food, but there is potential to use it for second-generation bioplastics. Several methods have been developed to remove color from RBCC, but they are expensive or may produce difficult-to-remove toxic residues. Hydrogen peroxide treatment is a cheaper alternative. The effects of RBCC concentration, pH, and reaction temperature were the most important factors influencing the decolorizing process. They were investigated with the aim of developing a method that could be scaled to commercial level for producing a bioplastic feedstock. Initial trials showed pH was an important factor for decolorization and foaming. At pH 15 there was a 96% reduction in solution color and 8.4% solids were lost due to foaming. There was a 76% reduction in solution color at pH 2 and only 2.6% solids were lost due to foaming. The optimal reaction conditions were to centrifuge 9% w/w, pH 2 aqueous RBCC solution to remove aggregates. The solution was reacted at 30°C with 7.5 g of 30% (w/w) hydrogen peroxide. These conditions achieved a 93% reduction in solution color after 3 hr and the molecular weight of the decolored protein was not significantly reduced.
authors.affiliation: School of Engineering, Waikato University, Hamilton, New Zealand. awk1@waikato.ac.nz
authors.forename: Aaron
authors.initials: A
authors.lastname: Low
authors.forename: Mark
authors.initials: M
authors.lastname: Lay
authors.forename: Johan
authors.initials: J
authors.lastname: Verbeek
authors.forename: Janis
authors.initials: J
authors.lastname: Swan
mesh_terms: D003116:Color; D004912:Erythrocytes / Q000378:metabolism*; D006454:Hemoglobins / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D010084:Oxidation-Reduction; D010969:Plastics / Q000138:chemical synthesis* / Q000737:chemistry*; D013696:Temperature
chemical_list: D006454:Hemoglobins; D010969:Plastics; D006861:Hydrogen Peroxide