Application Study Of The Fed-batch Fermentation In Two-step Fermentation Of Vitamin C

On the basis of deep analysis of the rules and kinetics in vitamin C two-step mixed culture fermentation, the process of batch fermentation and intermission fed-batch fermentation were studied and analyzed for the strain SD-2 witch endurance higher concentration of L-sorbose in culture medium by screened from strain improving. The higher productivity of the strain SD-2 was confirmed in the process of fed-batch fermentation. By comparing the processing conditions between shake flasks and fermentor, the aeration rate and the proportioning of medium were confirmed the two key points to improving the productivity in the scale-up experiments witch need studied in the 2L test-tank. The tests results of batch fermentation, constant fed-batch fermentation and intermission fed-batch fermentation were compared; the advantage of constant fed-batch fermentation was confirmed. This result is identical with the conclusion from the shake flask experiments. The optimization culture medium was obtained by the orthogonal experiment method.The scale-up experiments were done by the 2M3 airlift fermentor based on the results of 2L test-tank. The optimization aerate ratio of the strain SD-2 was confirmed which was 1:0.6～1:1.0 in the batch fermentation with the 2M3 airlift fermentor. The method of feed was established by kinetics model of the continuous feed process. Using the data on-line, the substrate decrease rate and the product increase rate can be calculated to control the concentration of substrate sugar fluctuation limited within 5mg/ml, by these works the strain SD-2 productivity in the 2M3 airlift fermentor reach the level in 2 L test-tank.The industrial experiment was done by the 160M3 airlift fermentor with the method of feed. The industrial experiment results showed this method improve the yield of vitamin C,a good economic benefit can be got.