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Evaluation microfiltration membranes for the recovery of solids and nutrients in corn wet milling coproduct
streams. C. I. THOMPSON (1), V. Singh (1), R. Simms (2), M. E. Tumbleson (1), R. L. Belyea (3), S.
R. Eckhoff (1), and K. D. Rausch (1). (1) Agricultural Engineering Department, 1304 W. Pennsylvania
Ave., University of Illinois, Urbana, IL 61801; (2) Technology, Inc., Fort Smith, AR 72916; (3) Animal
Sciences Department, University of Missouri, Columbia 65211.
Nearly 60 billion pounds of value added corn products are produced
annually from over 1 billion bushels of corn. Corn gluten feed and corn gluten meal (CGM) are coproducts
produced with starch in the wet milling process. Production of coproducts has increased due to the high
volume of starch processed for ethanol, high fructose corn syrup, and biodegradable plastics. Coproducts
must be dewatered and dried economically due to high levels of fiber, protein, and soluble carbohydrates.
Microfiltration (MF) of coproduct streams can provide feasible alternatives to centrifugation and vacuum
belt filtration, reducing high capital and energy costs. MF of coproduct streams retains suspended solids
while allowing water and soluble nutrients to pass through. Soluble proteins found in light steep water
(LSW) and light gluten (LG) can be recovered and added back to CGM, a high value coproduct of the wet
milling industry. In this study, the feasibility of stainless steel MF membranes to concentrate corn wet
milling coproduct streams was determined. Samples of LSW and LG were obtained from a commercial wet
milling facility. Permeate flux rates, volume concentration ratios, clean-in-place protocols, and nutritional
analyses of LG and LSW were measured using both a pilot scale system and an on-site system. Permeate
flux rates on LSW and LG measured 20-80 LMH. Initial volume concentration ratios of 6X-9X were
achieved for both samples. Levels of soluble and insoluble proteins were determined from MF LG samples
as well as on-site centrifuged samples. Economic analysis is discussed regarding MF as an alternative in
corn wet milling.
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