Study On The Liquid Culture Of Feather Meal By Mixed Strains And The Degradation Rate

Research shows that the crude protein content of keratin waste is more than80%and the amino acid content is more than70%, so the keratin waste has been recognised as a resource with high nutritional value. Although there are rich and huge quantity feather resources in China, the utilization of keratin waste is far lower than that in developed country. There are5processing methods of keratin waste such as chemical hydrolysis, extruding, enzymic hydrolysis and microbiological method. In recent years, most researches concentrated in utilizing keratin waste with microbiological method. However, the study on utilizing keratin waste with microbiological method was in the laboratory. It was the first time to scale up test for fermentation process on the basis of laboratory in our laboratory. The main results are as follows:1. The keratin-degrading bacterias were diluted into different multiple before fermentation, and then the treated keratin-degrading bacterias were inoculated in fermentation medium for fermentation. Finally, the dilution multiple and the optimal concentration were obtained by comparing the weight loss of feather meal under the conditions of different keratin concentration. The dilution multiple was8times and the the optimal concentration was2.9x108CFU/mL and4.4x108CFU/mL.2. In order to industrialize the utilization of waste feather by microbiological method, the scale-up of fermentation from shaking flask to5L ferm enter for the keratin-degrading bacterias based on the study of the best condition for fermentation in the laboratory. Finally, the results showed that he best condition for fermentation as follows:the initial PH value, the culture temperature, the air displacement, the stirring speed, the additive amount of feather meal and the fermentation time were7.4～7.6,37℃,3.5L/min,250r/min,210g and72h.3. A two-step enzymatic method of pepsin-pancreatin and a two-step method of stomach-intestine were used to evaluate the digestibility of fermentation products for swine, chicken and crucian. The results showed that, the digestibility of fermentation products of swine and chicken were higher than the digestibility of fermentation products of crucian. So it was concluded that the feather meal was more suitable for livestock feed.