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United States Department of Agriculture

Agricultural Research Service

Research Project: ENZYME-BASED TECHNOLOGIES FOR MILLING GRAINS AND PRODUCING BIOBASED PRODUCTS AND FUELS
2009 Annual Report


1a.Objectives (from AD-416)
The objective of this research project is to develop new, cost effective, alternative methods and engineering processes for corn processing and fractionation using enzymes, immobilized enzymes and other environmentally sustainable processes that maximize the yields of products and co-products (starch, protein, ethanol, oil, and fiber) and increase co-product market diversity and value while eliminating hazardous processing aids, such as sulfites.


1b.Approach (from AD-416)
This project was conceived and developed from the concept of taking a new approach to existing processes with the connecting element being enzymatic application. Many of the milling processes currently in use have been done in a similar fashion for over 100 years. By carefully reexamining what we know and don't know, and what works and what still has room for improvement we can use this to guide research towards beneficial modifications of existing processes and invent completely new design concepts. The experimentation for this project is constructed to cover fundamental research through design and economic assessment. Scale-up studies are incorporated into the plan where appropriate demonstration efforts and material are required. Process modeling and cost analysis are critical elements that are incorporated throughout the project design and are intended to aid in the overall process evaluation and to help identify potential problems early in experimentation.


3.Progress Report
During fiscal year 2009, research was conducted in the area of corn to ethanol processing. Previously we developed an enzymatic process that helps in the downstream dewatering process after ethanol has been produced. The research conducted continues to identify new enzymes that could potentially be more economically used in the process. This work has received interest from enzyme producers and led to the plant trial work described in the accomplishment below.

During fiscal year 2009, research exploring the importance of protein on the functional properties of corn fiber gum (CFG) was conducted. The protein rich components of CFG were separated from the protein deficient fractions using chemical extraction techniques and the emulsifying properties studied. The CFG with proteinaceous materials associated with it was a better emulsifier than one with protein-rich fractions removed. The CFG isolated from dry milling corn fiber was found to contain very little protein and was not as good an emulsifier. Using a protein conjugation method, the dry milled CFG was conjugated with a protein. The conjugated CFG was found to be an improved emulsifier relative to the unconjugated CFG. Finding the importance of protein in the functional properties of CFG prompted us to modify the protein deficient CFG by conjugating it with protein which increased its functionality. This finding will benefit corn growers, processors and food industries interested in utilizing CFG.

During fiscal year 2009, research was conducted on the production of astaxanthin from non-starch polysaccharide coproducts. This work is described in the technology transfer section below.


4.Accomplishments
1. First Application of ARS Energy-and Water-Saving Process in a Commercial Ethanol Plant: The current fuel ethanol process removes water, after ethanol recovery, using centrifuges, multi effect evaporators and driers to produce Distillers Grains with Solubles (DDGS). The drying process is very energy intensive and is a significant portion (about 45%) of the total energy used for ethanol production. The evaporators used are 3-5 times more efficient in terms of energy consumption for water removal relative to the drier. Researchers in the Crop Conversion Science and Engineering Research Unit found that it was possible to decrease the water binding capacity of the wet grains by adding a cell wall degrading enzyme preparation during fermentation. This enzyme treatment allows more water to be removed by the energy efficient evaporators and ultimately decrease the overall energy used by the ethanol production facility. The process also allows more water to be recycled in the ethanol process, a key issue in ethanol production today. This novel enzyme application was tested at a 54 million gallon per year corn to ethanol facility in the Midwest during 2008. The plant trial data confirmed the laboratory scale results and demonstrated that a 14% reduction in natural gas use in the DDGS drier was possible. This represents more than $1.2 million in potential annual savings for a 54 million gallon per year facility. A collaborative project to prepare improved enzyme formulations is being developed with Genencor, a Danisco Division, and a second trial to optimize the use of the existing enzymes and maximize energy benefits is being planned.

2. Distribution of Corn Wet-Milling Computer Models to Customers and Stakeholders: Researchers working on advanced corn wet-milling research at ERRC and elsewhere had no validated and publicly available wet milling process and cost model with which to understand the operation of current wet mills and to understand how proposed changes in technology might affect existing process. To solve this problem, a publicly available process model was previously developed and made available in several different software programs. Since then it has been requested by many industry engineers and scientists, academic researchers and other federal agencies. During FY 2009 the models were requested and distributed more than 10 times. These requests came from academics (both nationally and internationally) as well as from industry.


6.Technology Transfer

Number of New CRADAS1
Number of Invention Disclosures Submitted1

Review Publications
Ramirez, E., Johnston, D., Mcaloon, A.J., Singh, V. 2009. Enzymatic corn wet milling: engineering process and cost model. Biotechnology for Biofuels. 2:2.

Mikkonen, K.S., Tenkanen, M., Cooke, P.H., Xu, C., Hannu, R., Willfor, S., Holmbom, B., Hicks, K.B., Yadav, M.P. 2009. Mannans as stabilizers of oil-in-water beverage emulsions. LWT - Food Science and Technology. 42:849-855.

Nghiem, N.P., Montanti, J., Johnston, D. 2009. Production of astaxanthin from corn fiber as a value-added co-product of fuel ethanol fermentation. Applied Biochemistry and Biotechnology. 154:227-237.

Yadav, M.P., Johnston, D., Hicks, K.B. 2009. Corn fiber gum: New structure/function relationships for this potential beverage flavor stabilizer. Food Hydrocolloids Journal. 23:1488-1493.

Last Modified: 4/17/2014
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