Optimization Of The Conditions Of Compound Microbial Fermentation For Potato Residue

As a big country in producing potato, there are a lot of potatoes are processed into starch in China. But during this process there will be accompanied by produce a lot of waste like potato residue and juice, which contains large amounts of nutrients, direct discharge causes not only resource wasting, also leads to environmental severely damaged. This study use the growth and metabolism of microorganism to do the potato residue fermentation, and the degradation of cellulose was combined with the production of single cell protein. We use the starch waste to make the single cell protein to feed animals. This study determine the characteristics of the stains, find the optimum fermentation conditions of compound microbial fermentation of potato residue, and evaluate quality of the fermentation product, at last it’s about kinetic analysis of fermentation system by using mathematical method.The fermentation strains are Aspergillus niger which has the ability of cellulose degradation, and Saccharomyces cerevisiae and Bacillus licheniformis which can product single cell protein. Use the growth curve of the three stains and the situation of sugar production to determine the adding time of each strain. By determining the change of protein and the economic cost the fermentation period is chose by 4 days. The best condition of fermentation has been found by using response surface optimization, p H is 6.3, the inoculation amount is 2.61%, and the temperature is 33.94 ℃. In the verification experiment,the reduce of protein is 3.21 mg/m L and it’s close to the theoretical value 3.28 mg/m L. Then the kinetic model of potato residue fermentation is established, in under the optimum conditions of fermentation processes were detected and using 1st Opt software to fit the experimental data, respectively solution cell growth kinetics model, product formation kinetics model, animal consumption dynamic model and get the unknown parameters, determined the complete mathematical formula, to provide convenient for the large-scale production, guide the industrial application.The COD removal efficiency is 72.99% that compared with the untreated juice. The simple evaluation of the quality of the fermentation products from the aspects of physical, chemical and biological find the small particles of cellulose and protein is broken down after fermentation and that’s good for the animal to digest it. The protein reduce from 4.58 mg/m L to 1.37 mg/m L, crude protein increase to 31.8%, and the 17 kinds of amino acid content in fermentation are all increase, the total reached 15.8%, increased by 5.4 times. The degradation rate of cellulose was 55.4%, and the final reducing sugar was 0.015 mg/m L.