PNNL

Abstract

A new process is being developed to extract starch from millfeed, the low-value byproduct of wheat flour milling, and convert it to glucose through enzymatic processing. The millfeed-derived glucose will then be converted to value-added products, such as polyol, through a catalytic process, or lactic acid, through a fermentation process. The starch (glucose) recovery process has been tested through the pilot scale. Catalytic and fermentation processes have been tested in the laboratory. The process developed for glucose recovery from wheat millfeed includes hot water extraction of starch and filtration of a fibrous animal feed coproduct, followed by enzymatic liquefaction and saccharification of the extracted starch, with filtration of a high-protein coproduct. The bench-scale tests showed that a glucose yield of approximately 30% on a dry millfeed basis could be achieved, which corresponds to the recovery of essentially all the glucose value in the millfeed. Glucose yields with the pilot-scale system were comparable, although filtration was more difficult.