Solid-state Fermentation Of Cottonseed Meal With Mixed Culture Of Microorganisms

Cottonseed meal is one of high quality plant protein feed, and its protein content is 33.21%~45.09%, but the toxic material free gossypol influence on feed value. This study used the technology of mixed microorganism by Aspergillus niger Saccharomyces cerevisia and lactobasillus, decreasing free gossypol content and increasing true protein content on cottonseed meal, and making much higher the value of nutrition on feed with lots of lactobasillus.The free gossypol in cottonseed cake feed by HPLC. Free gossypol was immersed and extracted, after micropore filter, and then was analyzed by HPLC. The optimal conditions of HPLC were as follows: the column of chromatogram Sepax sapphire C185μm 120à(250mm×4.6mm), mobile phase acetonitrile/water(10mmol/L KH2PO4)=80/20, UV-238nm detector, column temperature 25℃, flow rate 1mL/min. The quantitative limit of gossypol was determined to be 0.94mg/kg, the average recoveries of the method were 96.23%~99.36%, and the RSD were 3.24%~4.02%. Compared with traditional chemical method, this method is reliable, simple, quick and accurately, and it seems to be an ideal method for determining the free gossypol in the cottonseed protein.The effects of mixed solid-state fermentation by Aspergillus niger and Saccharomyces cerevisia on detoxification and improving nutritional value of cottonseed meal (CSM) were investigated. The results showed that the optimal culture condition were as follows: inoculum 15%, initial pH 6, initial water content 0.96g water/g material dry base, fermentation at 30℃for 60h. The detoxification efficiency of free gossypol content in fermented CSM was 95.51%, and true protein content was increased from 32.99% to 42.40%, essential amino acids such as lysine, methionine and threonine were increased by 31.03%, 25.00%, 44.23%, respectively; nitrogen solubility index (NSI) was increased 1.49 times, and consequently the quality of CSM was improved.The study used cottonseed meal by mixed microorganism fermentation of pre and post for material, and the process conditions of lactobacillus used solid state culture, making the conditions as follows: inoculum 10%, initial water content 0.96g water/g material dry base, initial pH 6.4, fermentation at 30℃for 60h; after fermentation the lactobacillus quantity was 1.8×10~9cfu/g, increased the value of cottonseed meal.