Method for preparing dietary fiber flour from sweet potato starch production waste

The invention discloses a method for preparing dietary fiber flour from sweet potato starch production waste. According to the method, a dietary fiber is prepared from sweet potato residues and liquid waste generated in the sweet potato starch production process; the sweet potato residues and nutrient substances contained in the liquid waste are also utilized to cultivate acetobacter xylinum as a carbon source and a partial nitrogen source, and are fermented to prepare bacterial cellulose; the raw materials are fully utilized; meanwhile, methods for carrying out ultra-low temperature frozen pretreatment on the sweet potato residues and carrying out high-pressure gas impact-assisted mixed enzymolysis are adopted in the preparation process; and the yield of the dietary fiber flour is increased and the purity of the dietary fiber flour is improved. According to the method, the sweet potato starch production waste can be fully utilized; the yield of the dietary fiber is increased, and the purity of the dietary fiber is improved; and the pollution to environment caused by sweet potato starch production is reduced.