Studies On Screening The Strains Of Lipase Producing On Degrading Sesame Cake And Their Fermentation Conditions

Sesame is one of the traditional crops in China. We can gain sesame cakes and sesame meals through different extracting methods. Sesame cakes are made by traditional extracting method which is by crush and squeeze the oil from the sesame. Therefore, the residual oil remain in the sesame cake after extracted is over 80% more than the sesame meals. However, sesame does not have the efficiency amount of anti-nutritional factors (ANF) like oil tea cake do. So when use sesame as fermented fertilizer to feed animals and plants, it will affect the nutrient absorption rate. Moreover, all kinds of nutrient present in sesame cakes are relatively balanced and there is no obvious missing component that makes sesame caked a very good fermentation substrate.At the present stage in our country for the comprehensive utilization of sesame cake is relatively simple. This experiment to extend the sesame cake uses, increase its industrial use value as a starting point, screening mutagenesis and design a series of experiments. In order to can make full use of sesame cake of of all kinds of nutrients, especially to increase their use of crude fat.The bacteria strain used in experiment was taken from the soil sample in Changsha East abattoirs workshop and absolutely nature. Then the soil sample was process through first selection, mutagenesis, secondary selection, and molecular strain identification until it was identified as bacillus subtilis. After radiation mutagenesis of the strain the enzyme activity of it was increased 274% compare with before. And after subculture ten generations,3.8% of enzyme activity was changed. It's proves that they have strong genetic stability.To investigates the univariate determination and the orthogonal experimental determination of the culture condition, the sample was tested and determined the optimal culture conditions. Sample was fermented at pilot scale test in 50L fermenter under the optimal culture condition, Based on four factors and three levels orthogonal experiment which including inoculum size, rotation rate, temperature and ventilation, the optimal culture condition in the pilot scale test was determined. Used time-based gradients we tested on the enzymatic activity and biomass at different time gradients., and determine the optimal time in the pilot fermentation strains.