Study On Fermentation Of Fodder For Producing SCP From Corn Straw

Biological degradation of corn straw to produce Single Cell Protein was studied in this paper. The purpose of the research is to broaden feed stuff source and raise its quality by biologically transforming and utilizing recycle resources. The ultimate objects of this work aimed to solve the problem of shortage of grain and environmental pollution based on ecological balance and to promote agriculture development continuously as a kind of clean industry. Straw protein made for fodder into domestic chosen bran, wheat straw, sugar residue and other raw materials in major. And microbial degradation of straw was in the greater difference. In this paper, the corn stalk had been fermented to bio-production of single-cell protein from the bacteria screening, straw pretreatment methods and the optimal conditions for fermentation.On the basis of more than 500 of soil and biological residues samples collected by three grades undergraduate students who had worked in our laboratory, the samples had been treated by screening, purification and re-screening to separate the molds and yeasts. By analysising the results of the content of nitrogen, CMCase activity, the cell OD value and the weight of dry cells, the excellent yeast and mold which grew well in the corn straw had been selected for the production of single cell protein fermentation. And they are Trichoderma konigii NWM-364 and Candida utilis NWY-132.Using the different concentrations of acid, alkali, ammonia and methanol for pretreatment of the pre-crushed corn stalk, the best pretreatment method had been chosen by measuring on the reducing sugar content. Through comparison showed that 7% of the acid, 48 hours preconditioning, reducing sugar yield of 9.1% to reach. High temperature and ultrasonic pretreatment, liquid were measured at different times to deal with reducing sugar content. The results were quite clearly, 121℃for 40 minutes under treatment, reducing sugar yield reached 2.3%. In the economical and less polluting reason, the condition of 6% acid treated to the corn stalk for 48 hours had been decided, and to tie in high temperature and high pressure for 40 minutes as a straw pretreatment method.Depending on the content of the crude-protein, the best conditions of SCP fermentation have confirmed. The ratio of straw which had pretreated to the nutrition is 1:40. After high temperature sterilization, the Trichoderma konigii NWM-364 had been inoculated by 10% and fermentated on 31℃, pH 6 for 5 days. And after the second high temperature sterilization, the Candida utilis NWY-132 had been inoculated by 10% on pH 5, and then mixed fermentation for 12 days. The co-fermentation of Muti-fungus with corn straw can increase the crud protein content reaching to 29.6%.