Efficient Separation And Collection Of Aspergillus Niger Spores In Solid-state Fermentation

As one of the most important organic acids, Citric acid is widely used in food,beverage,medicine, chemical industry. metallurgy and other fields. Citric acid production by the traditional solid state fermentation can not only affect the citric acid production cycle, but also reduce the production of citric acid in the fermentation process, which is due to the different growth conditions of spore and mycelium and acid production conditions.Due to the strong regeneration ability of spores and the sufficient bacteria in the fermentation process, the fermentation of citric acid by Aspergillus niger Spores have a great advantage for unifying the fermentation cycle and increasing the yield of citric acid.To develop a set of equipment for the isolation and collection of Aspergillus niger spores is of great significance for the scale production of citric acid. In this paper, the physical parameters of mouldy bran are measured, the separating and collecting device of Aspergillus niger Spore is developed, and the device is used to optimize the experiment.The main research contents and results are as follows.Experiments on solid-state fermentation of Aspergillus nigerare carried out in conical flasks. The average particle size of granular bran is measured by sieving, and the average particle size is 2.26 mm. The true density was measured using drainage method, and the density is 456.87kg/m3. The packing density measurement result is 217.97kg/m3. These results provide basic data parameters for the development of the equipment for the separation of Aspergillus niger.In this paper. a set of equipment for separating and collecting Aspergillus niger spores is designed. The gas-solid fluidized bed can effectively separate the spores Aspergillus niger from solid bran, and the separation efficiency can reach above 90%. The cyclone separator collects the spores of Aspergillus niger. and the collection efficiency can reach above 80%. The spore powders are collected in the separator hopper, which is convenient for processing and packaging. Experimental study is carried out using the device. With the ventilation volume 80m3/h, the operating temperature 35?40? and the fluidization time of 90min, the collection rate reached the maximum of 2.28% (g spores /g solid bran) with a 300-400g solid bran added in the fluidized bed. The microscopy is used to measure the number of spores, which exist in solid bran before and after fluidization. Before the separation, the number of spores is 109 in 1g solid branL and after separationL the number reduces 107. In order to achieve the standard of citric acid fermentation, the content ofspores in per gram bran must reaches 10 . It can be concluded that the fluidized bed have an effective separation on the separation of Aspergillus niger spores, which grow in solid bran.