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United States Department of Agriculture

Agricultural Research Service


Location: Biobased and Other Animal Co-products Research

2012 Annual Report

1a. Objectives (from AD-416):
1) Produce functional protein isolates from animal by-products. 1a. Develop a pilot scale process for producing poultry blood-based flocculant. 1b. Increase the yield and molecular weight of soluble peptides extracted from rendered animal protein. 2) Utilize animal-protein isolates in biobased applications. 2a. Broaden the application range for animal protein-based polyacrylamide (PAM) substitutes. 2b. Develop practical processes for the production of fermentation feedstocks derived from animal by-product proteins. Evaluate these feedstocks in fermentation systems.

1b. Approach (from AD-416):
Meat animal processing inevitably yields by-products, which include tissues and organs that are unsuitable for human food, such as feathers and bones, or for which there is low food market demand, such as blood. The current outlets for animal by-products, either through profitable use or disposal in the environment, are limited and shrinking. The proposed project is designed to create new utilization opportunities for these substances and reduce the environmental impact of meat processing. Two groups of promising applications are targeted here, use as fermentation feedstocks and use as renewable alternatives for synthetic polymeric flocculants such as polyacrylamide (PAM). Rendered protein will be processed into forms well-adapted for use in non-pharmaceutical industrial fermentations. Poultry blood and substances derived from rendered proteins will be tested in applications including algae culture flocculation, ethanol whole stillage clarification, mine tailings flocculation, cellulosic fiber flocculation, and municipal sewage sludge settling. At all stages, emphasis will be placed on employing processing techniques that are appropriate to the relatively low value of the products to be produced. Successful completion of this project will yield technologies that can be commercialized in a relatively short time period and produce new revenue streams for renderers and meat processors, while benefiting the environment.

3. Progress Report:
Flocculants are substances which help in clarifying liquids by causing suspended particles to settle more quickly; they are employed in a wide variety of industrial, agricultural, environmental and construction applications. Development of both bio-based and synthetic polymeric flocculants is a very active area of research. The tools available for measuring and comparing the performance of polymeric flocculants, though, are non-standardized and weak in a number of technical respects. In FY2012, we took a systematic approach to designing a method better suited for research into polymeric flocculants. Using a variety of flocculants, we crafted a method that is robust, sensitive and reliable. It employs a relatively inexpensive instrument, and a special buffer system adopted from another area of research. Our own flocculant research has progressed along a couple of fronts. In previous reporting periods we have shown that hemoglobin from poultry blood is promising as a biobased flocculant; the source material (blood) is a by-product that is burdensome to the poultry industry, and its technical performance as a flocculant is very strong. In FY12, we began work on design of a practical process for producing hemoglobin-flocculant from raw poultry blood at a pilot plant scale. This task is difficult because the flocculant properties of hemoglobin are diminished if it is not processed carefully, yet the processing costs must be kept very low. Our work in the past year has focused on the initial steps of the processing, where blood is collected and stored, while preventing clotting and red blood cell breakage. In investigating existing technologies for this purpose we found that while many were too expensive for our purposes, they were also overkill. We showed that significantly lower concentrations and lesser grades of anti-coagulant and preservative chemicals were adequate for non-medical blood processing. Meat and Bone Meal (MBM) is another promising source material for producing bio-based flocculants. The technical difficulty with using MBM in this application is the material’s very poor solubility. In past reporting periods we found that MBM protein could be solubilized through harsh alkaline or non-selective enzymatic treatments, but that such treatments sacrificed much of the potential flocculant activity in the material. In FY12, we found that most of the protein in MBM can be solubilized using much milder enzymatic treatments, resulting in products with better flocculant properties. These enzymatic treatments make only very selective cuts in the protein chain, resulting in bigger, more functional protein fragments. This research is an advance towards the specific goals of the CRIS project, but it could also serve as a starting point for development of an MBM-based adhesive.

4. Accomplishments
1. A method for measuring the performance of flocculants. Flocculants are substances which assist in clarifying liquids by causing suspended particles to settle more quickly. Flocculants are used in agriculture for applications such as erosion control or manure treatment, and experimental flocculants are also being produced from agricultural by-products. Research and development into new flocculants requires methods for measuring flocculant performance, but the available methods are poorly designed. ARS researchers at Wyndmoor, Pennyslvania, have developed a flocculant performance measurement method that is robust, sensitive and reliable, using only inexpensive equipment and chemicals. This accomplishment will make flocculant research more productive, indirectly benefitting those in agriculture who are either flocculant users or producers of the raw materials to make flocculants.

Review Publications
Piazza, G.J., Nunez, A., Garcia, R.A. 2012. Identification of highly active flocculant proteins in bovine blood. Applied Biochemistry and Biotechnology. 166(5):1203-1214.

Liang, Y., Garcia, R.A., Piazza, G.J., Wen, Z. 2011. Non-feed application of rendered animal proteins for microbial production of eicosapentaenoic acid by the fungus Pythium irregulare. Journal of Agricultural and Food Chemistry. 59(22):11990-11996.

Garcia, R.A., Phillips, J.G., Adeola, O. 2012. Improved prediction of meat and bone meal metabolizable energy content for ducks through in vitro methods. Poultry Science. 91:1854-1859.

Last Modified: 06/24/2017
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