Application Of Lactobacillus Casei In Laobaigan Flavor Liquor

In this paper, Lactobacillus casei HJB-006 which isolated and screened from medium-temperature Daqu of Laobai-gan was used as experimental strain. Culturing conditions of the cells have been optimized and used for the large-scale brewing fermentation to increase ethyl lactate content of base wine after three-grade expanding cultivation under the optimized conditions. Acid-producing culturing conditions of the cells have been optimized and study on aqueous two-phase system,which have been established to separate lactic acid from the cells fermentation liquids.Medium and culture conditions of Lactobacillus casei HJB-006 was optimized by single factor and orthogonal experiments, the medium and optimal culture conditions were: Soybean peptone 1.0%, sucrose 2.8%, Fe2+ 2.3 ×10-4 mol/L, Mn2+ 3.0 ×10-3 mol/L, Mg2+3 ×10-4 mol/L, ferrous sulfate 0.03 g/L, manganese sulfate 0.57g/L, magnesium sulfate 0.106 g/L, and 0.4% triammonium citrate, sodium acetate 0.6%, initial pH value of 7, Culture conditions:medium volume 65mL, incubation time 72h, inoculum 1%, incubation temperature 36℃, the bacteria under the OD600 absorbance value was 0.82, increased by 64.66% compared with that before optimization.Ethyl lactate content was significantly increased in base distilled wine when used the strain in large brewing fermentation under low temperature conditions in winter. When the cell concentration of wine fermented grains was 4.0 × 106 cfu/g, the content of lactic ester was 332.58 mg/100mL, which increased by 350.35% than the blank which inoculated no bacteria, and had no side effects on other indicators. Wine critic members taste and evaluated that when the cell concentration was 3.5 × 106 cfu/g,the taste was the best, lactic ester content was increased by 145.56%, and the lactic ester reached to 181.32 mg/100mL, ethyl acetate content was 100.77 mg/100mL, and at this time, ethyl lactate to ethyl acetate was 1.80, which was in line with the requirements of ethyl lactate to ethyl acetate is higher than 0.8.,as high quality wine of Laobaigan flavor Liquor.The best medium and culturing conditions of bacterial acid producing fermentation were determined by single factor and orthogonal experiments, and PEG/DEX aqueous two-phase system for isolation lactic acid was established, miscellaneous protein, bacteria concentrate into the next phase, to achieve the separation of, and lactic acid extraction rate reached to 96.97%.