The projected expansion of the corn processing industry over the next decade will likely result in severe oversupply conditions for the related animal feed co-product markets. Today, the proteins of processed corn are sold either into ruminant feed markets that place little value on amino acid profiles, or into poultry markets where the pigment content, rather than the amino acid profile, is the key factor for diet formulation. This proposal examines a novel concept for reforming the amino acids in corn by using non-gas forming anaerobic bacteria in a fermentation step that co-produces fuels and chemicals. The cell mass produced by the fermentation can be processed into a high protein concentrate suitable for use as an animal feed ingredient. Phase I will show that reforming the native proteins of corn in this manner will result in a more valuable feed co-product slate. This concept could also broaden the markets in which corn derived proteins compete, thereby reducing oversupply pressures induced by expansion of the industry. OBJECTIVES: The technical objectives of Phase I are: 1) To show that Lactobacillus can transform hydrolyzed corn protein into bacterial protein containing an amino acid profile higher in essential amino acids. 2) Determine the value of the resulting bacterial cell mass as an animal feed ingredient. APPROACH: The technical objectives will be met by conducting a series of batch fermentations around which careful nitrogen balances have been conducted to determine whether, and to what extent, hydrolyzed corn proteins have been reformed into bacterial cell mass. The work plan has been divided into four tasks: Task 1 - Shake Flask Fermentations: Lactobacillus sp. ATCC 53103 will be will be revived from the library deposit and adapted to a media based on corn protein hydrolyzate. The corn protein hydrolyzate will be prepared from ground corn using an enzymatic milling process as outlined in the proposal. Substrate disappearance and end product formation will be monitored by HPLC analysis using a Biorad HPX 87H column with a 5 mM sulfuric acid/water mobile phase. Cell density will be monitored by spectrophometry at 600 nm. Task 2 - Batch Fermentations and Work-up: The media developed in Task 1 will be used in scaled-up pH controlled batch fermentations so that enough cell mass can be generated for proximate analysis, amino acid profiling, digestibility and nucleic acid determination. The cells will be harvested by centrifugation and washed several times with sterile water to remove residual media. The cell pellet will be weighed, shell frozen and lyophilized overnight. Lactic acid will be separated from the supernatant by first acidifying it with sulfuric acid, filtering to remove the calcium sulfate precipitate, followed by solvent extraction with isoamyl alcohol or similar conventional organic solvent. Each of the starting materials and endproducts will be weighed and analyzed by HPLC for carbohydrates and organic acids. Nitrogen rich materials (i.e. the starting media and inoculant, the cell mass pellet, calcium sulfate precipitate, and the residue syrup) will be sent to outside labs for proximate analysis (total carbohydrate, fat, protein, ash, water, caloric value) and amino acid profile as appropriate. An overall material balance and atom balances on carbon and nitrogen will be assembled. Task 3 - Evaluation: Representative samples and the analytical results on proximate analysis and amino acid profiles will be provided to our consultant, Dr. Michael Kidd, for evaluation as potential ingredients in poultry feed formulations. Samples sent to Dr. Kidd will include: the cell mass pellet from fermentation, the residue syrup from broth work-up, and a dried sample of the solids remaining after cellulose/hemicellose hydrolysis (i.e. the initial insoluble corn proteins, which should be similar to corn gluten meal in properties). In addition to a qualitative analysis, Dr. Kidd will conduct linear programming calculations to establish a preliminary value for each of the individual materials and for a blend of the cell mass pellet and residue syrup. He may also make specific recommendations on approaches to improve the value of the materials. Task 4 - Reporting: One original and two copies of a brief interim progress report will be submitted to USDA by September 1, 2005. One original and two copies of a comprehensive final report will be submitted by January 30, 2006. One Financial Status Report (SF-269) will also be submitted by March 30, 2006
