Performing Department
(N/A)
Non Technical Summary
Rice bran is an underutilized co-product of the rice processing industry and may be used as an inexpensive substrate for the production of yeast. If the proposed process is shown to be more economical than production of yeast in molasses, the rice processing industry will benefit from increased value of rice bran and the yeast production industry will benefit from lower production costs.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
This Phase I project will optimize the growth in heat-stabilized, defatted rice bran (HDRB) of several strains of Saccharomyces cerevisiae yeast in an automated bio-reactor. After activating yeast from frozen stock, the conditions for growth of yeast inside the automated bioreactor will be optimized. The strain that performs best will be selected for further study in Phase II. Additional factors that will be considered in the selection of yeast strains include marketability of the strain and characteristics of the co-products of yeast fermentation. The specific Phase I objectives are: 1. Conduct and demonstrate the feasibility of producing yeast from HDRB using an automated bioreactor. 2. Optimize HDRB:water ratio and time of incubation to produce maximum amount of yeast from HDRB. 3. Optimize the temperature and pH, to produce the maximum amount of yeast from HDRB. 4. Demonstrate the maximum amount of yeast produced when conditions under objectives 2 and 3 are
integrated. The Phase I work will establish the feasibility of the automation of the process. In Phase II, the work will be extended to pilot-scale testing in coordination with Riceland Foods, our commercialization partner, and in coordination with yeast manufacturers.
Project Methods
Yeast fermentation in heat-stabilized defatted rice bran (HDRB ) is a promising technology to reduce the cost of production of yeast. HDRB contains the essential nutrients for the growth of yeast in a complex form and does not require the addition of nutrients as is required in the commercial scale production of yeast using food grade molasses. The HDRB contains 10.5-12.0% moisture, 18.5-20.9% protein, 1.5-2.0% lipid, 15.3-16.8% starch (from broken endosperm), 25.2-25.6% total fiber, 0.5-0.7% total phenolics, 1.73-2.28% phytic acid, and 9.0-10.4% ash. In addition, rice bran also contains vitamins (Thiamin 2.75 mg, Riboflavin 0.28 mg, Niacin 33.00 mg, Pantothenic acid 7.39 mg, Vitamin B-6 4.07 mg, Folate 63 ug, Vitamin E (alpha-tocopherol) 4.92 mg, Vitamin K (phylloquinone) 1.9 ug per 100 g) and minerals (Ca 57 mg, Fe 18.54 mg, Mg 781 mg, P 1677 mg, K 1485 mg, Na 5 mg, Zn 6.0 mg, Cu 0.7 mg, Mn 14.2 mg, Se 15.6 ug per 100g). The growth performance of yeast in HDRB in
manual studies has been demonstrated by the Nutraceutical Innovations team. In this Phase I proposal, the production of yeast using HDRB will be optimized using an automated fermentation system .