1. Graduate research assistant, South Dakota State University, Brookings, SD 57007.
2. Bioprocess engineer, North Central Agricultural Research Laboratory, USDA – ARS Brookings, SD 57006.
3. Corresponding author. Phone: (605) 693-3241. Fax: (605) 693-5240. E-mail address: krosentr@ngirl.ars.usda.gov
4. Professor, South Dakota State University, Brookings, SD 57007.