| The fruit production and acreage in China are at the head of the world. At the same time, pomace production reach nearly 10 million tons per year. If this problem was not dealt with in time, it would cause a serious waste of resources,but also cause environmental harm. Producing feed with probiotic is a way to achieve full utilization of pomace. This way has no environmental secondary pollution, low cost and with a high added value. Seen from the current study,most methods are solid-state fermentation. But this method has its limitations in terms of large-scale industrial production. In this study, fresh pomace was as the main material. The method of liquid-submerged fermentation was used for fermentation. Eventually got the product containing a lot of probiotics and true protein in it had also improved significantly. Then the dynamic model was built,it provide a basis for industrial production. The results of this study were as follows:The results of single factor experiment: Adding carbon sources in the pomace medium to culture Saccharomyces cerevisiae MB(Hereinafter referred to as MB), prominence order of cell growth was: brown sugar> glucose> sucrose>corn flour. The largest number of viable cells reached to 8.6×107cfu/m L when adding brown sugar in the pomace medium. Adding nitrogen sources in the pomace medium to culture MB, prominence order of cell growth was: urea>yeast powder> peptone> whey powder> ammonium sulfate. The largest number of viable cells reached to 5.06×107cfu/m L when adding urea in the pomace medium. Adding vegetables in the pomace medium to culture MB,prominence order of cell growth was: carrot> chinese cabbage> white radish>cucumber> wax gourd> green pepper> celery> cabbage. The largest number of viable cells reached to 5.4×107cfu/m L.The results of multi-factor experiment: Used four groups of L9(34)orthogonal test with adding brown sugar as carbon source, urea as nitrogen source and four kinds of vegetable as growth factor in the pomace medium toculture MB. The number of viable cells all reached to more than 108cfu/m L in the four groups of different combination. Used the method of all factors test with adding brown sugar as carbon source and four kinds of vegetable as growth factor in the pomace medium to culture MB. The ideal combinations were: 4%brown sugar+3% white radish, 4% brown sugar+3% cucumber, 4% brown sugar+3% carrot and 3% brown sugar+3% chinese cabbage. The number of viable cells all reached to more than 108cfu/m L in the four mediums. The addition of ture protein respectively were: 43.61g/kg, 46.66g/kg, 50.94g/kg and51.14g/kg. The growth condition of MB was well by microscopical observation.Used the method of all factors test with adding brown sugar as carbon source and urea as nitrogen source in the pomace medium to culture MB. The ideal combination was: 3.5% brown sugar+0.5% urea. The largest number of viable cells reached to more than 108cfu/m L. The addition of ture protein was73.22g/kg. The growth condition of MB was well by microscopical observation.The results of the experiment about other probiotics: Used the five mediums chosened to culture Saccharomyces cerevisiae MC(Hereinafter referred to as MC), Candida-utilis B203(Hereinafter referred to as B203), Hansenula polymorpha B160(Hereinafter referred to as B160), Geotrichum candidum B40(Hereinafter referred to as B40), Geotrichum candidum B41(Hereinafter referred to as B41), Pichia kudriavzevii XY1(Hereinafter referred to as XY1),Issatchenkia orientalis XY2(Hereinafter referred to as XY2) and Trichosporon asahii BJ31(Hereinafter referred to as BJ31). The viable cell numbers of MC and B203 all reached to more than 108cfu/m L. The largest addition of ture protein were 63.29g/kg and 58.58g/kg respectively. The growth condition was well by microscopical observation. The medium surface covered with hypha after culturing B160, B40 and B41 one day respectively. Velum became thicker after cultured more than two days. Hypha grew again after flipping the medium. The largest addition of ture protein were 61.75g/kg, 62.71g/kg, 59.18g/kg respectively. The viable cell numbers of XY1, XY2 and BJ31 all didn’t reach to108cfu/m L. The growth condition was relatively poor.The results of dynamic model: The pomace medium added 3.5% brown sugar and 0.5% urea was selected to culture MB. Used gradient test about initial p H, temperature and charge amount to culture MB in advance.The optimum conditions were: natural p H, 28℃, 70% charge amount. Used the containers of 250 m L, 500 m L, 1L and 3L for expand culturing in turn. It was confirmed that the stability of the medium was good. Then used the 5L fermenter to culture MB and recorded the change of the parameters in the fermentation process. The fitting function of cell growth model, product formation model and substrate consumption model respectively were:Contrasted the experimental values of verification test with theoretical value,the error was small. The largest number of viable cells reached to5.04×108cfu/m L. The largest addition of ture protein reached to 143.68g/kg, the protein content increased from 17.02g/kg to 160.7g/kg. The growth condition was well by microscopical observation. Dynamic model constructed in this study can describe the variation of cell growth, true protein growth and reducing sugar consumption well. |
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