| Setting out in this paper, research work is based on bacillus licheniformis strains, the high-yield 2,3-butanedione of two strains using mutagenic treatment BED-4. BED-4 strains medium conditions are determined on butanedione fermentation conditions.The fermentation conditions are as follows:the final source of nitrogen ratio for 0.5%, yeast extract nitrogen source D1.7%, the best carbon source is slag corn sugar with 10%, not adding sodium citrate, corn sugar 10%. The best ratio of medium is:slag nitrogen source D1.7%,0.5% yeast extract,0.15% magnesium sulfate and other inorganic salts and trace elements, pH7.2～7.4. Culture conditions are:fermentation temperature 30℃, bottled capacity is 60 mL,500 ml triangle table speed 180 r/min, quantity of 5%,38 h. Under the optimum fermentation conditions, the determination of total nitrogen is 0.25%, C/N ratio is 40/1. Experiments showed that the fermentation yield can reach more than 20 g/L, when fermentation medium C/N ratio is 25/1～50/1.Based on the experiment, we explored the parameters of pilot process,in which the 2,3-butanedione is producted by bacillus licheniformis with fermentation method. The optimum ratio of pilot medium is:corn candy slag 8%(taking account of the filtrate contained glucose), nitrogen source D 1.7%, yeast extract,0.5% MgSO40.15%, other trace elements, defoamer S 0.4‰, pH 7.0～7.4, bacterial species quantity of 5%. Fermentation ended when fermentation liquid backing to pH 7.2,3-butanedione is the objective production.2,3-butanedione can be purified through the process of evaporation, oxidation, distillation, distillation, etc. This process is simple with high rate of recovery. With this process, the purity of objective production can reach more than 95%. According to the application report, this production has the aroma of butter, small irritant and clean aftertaste. It has a typical cream flavor after dilution and can be used as main flavor to blend edible milk essence and other food flavor. |
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