Research Of The Productive Technology Of Feeding Concentrated Bacillus Natto Powder

Bacillus natto is one of probiotics that was permittied to be usd in animal feed byState Agricultural Department.This dissertation research the high density cultivation、the generation of spores and the high efficiency of spores recycling by Bacillus nattoAJ318.The optimal medium of Bacillus natto AJ318is found using Glucose15g/L、Soybean cake powder10g/L、（NH4）2SO₄5g/L、Na₂HPO₄1g/L、NaH₂PO₄1g/L、NaCl5g/L、MnSO₄·H₂O0.02%、CaCl₂0.02%、FeCl₂0.02g/L、MgSO₄0.015%.The optimal fermentation condition are follows： pH7.0、 temperature37℃、Inoculation4%、liquid volume50%，and shaking speed220rpm. In scale-upculture in50L fermenter, Promoting the generation of spores by subsection controltemperature、controling temperature and adding the spore inducing agent in the20thhours.And the bacterium amount was3.05×10⁹cfu/mL、 the spore amount was2.98×10⁹cfu/mL、thespores rate was97.7%when the cultivating finished.The production of Bacillus natto powder used the equipments of Centrifugalspray dryer and Tri-effects film evaporator. Setting the discharge concentrations is20%，the optimization of process parameters as the first effect: heating temperature85℃、 evaporation temperature70℃、 concentrated liquid temperature75℃、evaporation300kg/h；the second effect：heating temperature75℃、evaporationtemperature60℃、concentrated liquid temperature70℃、evaporation90kg/h；thethird effect：heating temperature65℃、evaporation temperature50℃、concentratedliquid temperature60℃、evaporation120kg/h. The process parameters of Centrifugalspray dryer is: constant flow35L/h、pressure2MPa、entrance temperature180℃、exit temperature80℃、spray nozzle speed12000rpm、time of spray drying25s,anduse starch as the protective agent. Under this process conditions, the Bacillus natto powder was homogeneous andpure，and the moisture content is5%,the spore amount of Bacillus natto powder wasup to6.1×10¹⁰cfu/g.