Fermentation of rapeseed meal to prepare peptide by mixed strains

The peptide content in fermentation products was taken as an evaluation index,fermentation conditions of rapeseed meal to prepare peptide by mixed strains of Geotrichum candidum and Bacillus subtilis.Experimental results of Plackett- Berman showed that significant factors affecting peptide content were whether sterilization,fermentation temperature and fermentation time.Mathematical model predicting peptide content in fermentation products was obtained by single factor experiments and response surface experiments as follows: Y = 154.90 + 7.64X4-1.10X5 + 4.75X3-1.52X4X5-5.84X42-11.56X52-5.42X32,where X3 was fermentation time(d) ,X4 was fermentation temperature(℃) and X5 was inoculation concentration(%) .There was a significant interaction influence on the polypeptide between fermentation temperature and inoculation concentration.Optimum fermentation conditions were that fermentation temperature was 35.68℃,inoculation concentration 18.68% and fermentation time 4.25d.And under fermentation conditions,peptide content in fermentation product was 157.79mg /g.