Studies On High Biotin Forcing Fermentation Techniques By Temperature-sensitive Producing L-Glutamic Acid Bacterium

Temperature-sensitive producing Glutamic acid bacterium, which used in this article, is more vexatious strain in glutamate fermentation industry. After studying its nutrition characteristic, the results indicate: it can yield glutamate by using crude material such as crude corn hydrolyzes, molasses etc. in fermentation medium, also show that adding some beet molasses in medium not only can elevate its yield level, but also can reduce the biotin dosage in medium, and still show high biotin quality in its nutrition demanding. Based on original fermentation medium, the Beet molasses, d-biotin, MnSO4, VB1 in fermentation medium were studied by using the Plackett-Burman design and Central Composite Design in this experiment. Then two quadratic regression models were built up, which were of high predication. By use of two models and experiment results the new fermentation medium,which is fit for strain's growth and yielding, was obtained as follow: Starch hydrolyzes 30g/l,BM 30g/l,d-biotin 260μg/l,MnSO4 0.026g/l,VB1 220μg/l, KH2PO4 4g/l,MgSO4 1.5g/l,FeSO4 0.03g/l,defoaming reagent:0.05ml/l. The biotin dosage was reduced by 240μg/l,compared with original fermentation medium. After investigating temperature changing and dissolving Oxygen level of fermentation conditions, the results indicate: temperature changing twice is more fit for the strain's fermenting techniques. For the strain were cultured in nutritious medium and grows well, ventilating quantity and stirring speed should be elevated in yielding phase, so that it can increase dissolving Oxygen transferring speed and avoid Lactic acid synthesizing. Under the optimum, the strain's average yield is up to 15.06%, the average trans-formation rate is up to 71.15%, and the average fermentation period is 30 hours,Compared with the medium before optimization, the average glutamate yield was increased by 4.98% and the average trans-formation rate by 22.08%. The curves of ferment discourse show: the strain grows well, yields acid quickly and consumes sugar calmly after optimization,and all those results indicate: The strain's fermenting performance was enhanced. The groundwork for next magnifying produce was settled; also the research method and result are of significance to help ferment control in big jar fermentation.