微生物干预降低酱香型白酒酿造中的乳酸

Microbial intervention to reduce lactic acid in Moutai-flavor liquor brewing

为探究酱香型白酒中毕赤酵母与不同乳酸菌的相互作用,了解菌株的发酵性能,为通过生物途径降低白酒发酵过程有机酸的含量提供理论基础。采用可培养方法,从酱香型白酒酒醅中筛选降乳酸的毕赤酵母菌株,并对菌株进行26S rDNA分子生物学鉴定,将目标菌株与酱香型白酒中6株主要乳酸产生菌(植物乳杆菌、桥乳杆菌、面包乳杆菌、乳酸片球菌、发酵乳杆菌、食果糖乳杆菌)混合发酵,分别测定发酵产物乳酸、总醇含量;将该研究的毕赤酵母制备成强化菌剂添加于白酒生产过程中,进行降乳酸的应用研究。从酱香型白酒发酵酒醅中初步筛选得45株乳酸耐受性较强的目标菌株,其中21株经26S rDNA分子鉴定为库德里阿兹威氏毕赤酵母(Pichia kudriavzevii);菌株JP-Y08与植物乳杆菌、乳酸片球菌、桥乳杆菌或面包乳杆菌混合发酵,可使混合发酵体系的乳酸含量下降64.0%~94.1%,抑制效果远高于毕赤酵母模式菌株;毕赤酵母与同型、异型乳酸菌混合发酵产生的乳酸明显低于乳酸菌纯种单独发酵组别,且毕赤酵母接种量越高,乳酸含量越低,毕赤酵母对异型乳酸发酵的产乳酸抑制作用强于同型乳酸发酵;添加毕赤酵母可以优化酒醅微生物结构,改善酒醅发酵状态,降低酒醅中有机酸含量。

The interaction between Pichia kudriavzevi and lactic acid bacteria strains were investigated to provide a theoretical basis for reducing the content of organic acids by bioaugmentation inoculation in Moutai-flavor liquor fermentation.Pichia strains that can degrade lactic acid were isolated form fermented grains and were identified by 26S rDNA molecular biology.Then Pichia was separately mixed with Lactobacillus plantarum,Lactobacillus pontis,Lactobacillus panis,Pediococcus acidilactici,Lactobacillus fermentum,and Lactobacillus fructivorans for fermentation.After fermentation,lactic acid and total alcohol were determined.Finally,the Pichia strain with excellent characteristics was inoculated into liquor fermentation to achieve the reduction of lactic acid in liquor.A total of 45 strains with strong lactic acid tolerance were isolated from fermented grains,and 21 strains were identified as Pichia kudriavzevii.P.kudriavzevii JP-Y08 had the strongest inhibition on the lactic acid production and can reduce lactic acid by 64.0%-94.1%when was fermented with L.plantarum,P.acidilactici,L.pontis,and L.panis.In addition,lactic acid produced by mixed fermentation was significantly lower than that in the fermentation by single lactic acid bacteria.Moreover,the higher the inoculation amount of P.kudriavzevii was,the lower the lactic acid content was.Finally,inoculation with P.kudriavzevii JP-Y08 during fermentation optimized the microbial structure,improved the state the fermented grains,and reduced the lactic content.