The Recycled Utilization Method Of Potato Starchy Processing Waste

In recently years, with the development of potato starch processing industry, people have raised great concern about the treatment of potato starchy waste. Two methods of potato starchy processing waste were tried in this paper. Firstly, a process utilizing the liquid fermentation of mycelial fungus Rhizopus oryzae to treat the potato starchy waste was studied, and a novel coupling method of extractive fermentation of lactic acid with iron resin was applied. The improved method successfully alleviated the inhibition to lactic acid-producing R. oryzae growth and fermentation. Secondly, we use the waste water as raw material to extract potato protein including protease inhibitors by a series of methods of protein isolation and determinate the inhibitory activity of protease inhibitors. Taken together, it was to convert waste residue and waste water of potato processing to useful products.We have tested that the protein content of potato waste mill is about 0.83%, and the protein content of waste water after concentration is about 1.68%. It is suitable for fermentation as medium.Moreover, it is also can be used to extract protein for fodder.To combine with other waste water treatment methods for the processed water, we can realize the recycled utilization or discharge of waste water. The results of these experiments are as follows:(1) The improved method successfully alleviated the inhibition to lactic acid-producing R. oryzae growth and fermentation. The yield of acid reaches 12.59g/L, and the convertion rate for glucose is 79.9%, which is increased by 21% than the method of addition with CaCO3. The total carbohydrate content has been decreased greatly from 19.6% to 3.8% in the course of fermentation.(2) Potato protein was successfully extracted by a serial of methods including PI sedimentation, centrifugalization, heating and so on. A kind of proteinase inhibitor was further separated and purificated. The inhibition rate to trypsin activity is 76.82%.(3) The COD value of potato starchy waste water has totally dropped 30.2% after the protein extraction and active carbon adsorption process.So the yield of lactic acid has increased by the coupling process, and this has provided new method for acid fermentation. Not only the potato protein was extracted, but the waste water was purified after the PI sedimentation and heating process.