产胞外多糖乳酸菌的筛选及抗氧化特性研究

Isolation of exopolysaccharides-producing lactic acid bacteria and its antioxidant properties

以分离自贵州侗族、苗族传统发酵食品的36株乳酸菌为受试菌,筛选出8株高产胞外多糖（膜截留分子质量为8 000-14 000u）的乳酸菌,分别为SR2-1 （Pediococcus sp.F3S1）、SR2-2 （Pediococcuspentosaceus NGRI0304）、SR3-2 （Pediococcus pentosaceus LB-WC）、SR8 （Lactobacillus kimchi）、SR10-2 （Pediococcus sp.22-4）、SR 12-1 （Lactobacillus graminis）、H1 （Staphylococcus sp.3034O2）和XS2 （Pe-diococcus pentosaceus GS17）,并对其胞外多糖进行体外抗氧化特性研究.结果显示,8株乳酸菌的胞外多糖均具有抗氧化活性,其中胞外多糖质量浓度为30μg/mL时,乳酸菌SR2-2、SR8和SR12-1的胞外多糖对Fe^2＋的清除率分别为15.55％、12.41％、53.21％;胞外多糖质量浓度为40 μg/mL时,乳酸菌SR2-2、SR8和SR12-1的胞外多糖对1,1-二苯基-2-三硝基苯肼（DPPH·）和NO2-的清除率分别达9.69％、11.93％、8.93％及5.73％、7.82％、3.82％.这三株乳酸菌显示出一定的抗氧化活性.

Using 36 strains of lactic acid bacteria （LAB） isolated from fermented food of Dong and Miao nationality in Guizhou as tested bacteria, eight LAB strains with high yield exopolysaccharides （EPSs） （membrane molecular weight （Mw） cut off： 8 000-14 000 u） were preliminarily screened, including R2-1 （Pediococcus sp. F3S1）, SR2-2 （Pediococcus pentosaceus NGRI 0304）, SR3-2 （Pediococcus pentosaceus LB-WC）, SR8 （Lactobacillus kimchl）, SR10-2 （Pediococcus sp. 22-4）, SR12-1 （Lactobacillus graminis）, HI （Staphylococcus sp. 303402） and XS2 （Pediococcus pentosaceus strain GS17）. in vitro antioxidant properties of exopolysaccharides were investigated. The results indicated that the exopolysaccharides of eight LAB strains all had antioxidant activity. At the EPS content of 30μg/ml, the clearance rates of Fe^2＋ of SR2-2, SR8 and SR12-1 were 15.55%, 12.41%, 53.21%, respectively. At the EPS content of 40 μg/ml, the clearance rates of DPPH · and NO2^- of SR2-2, SR8 and SR12-1 were 9.69%, 11.93%, 8.93% and 5.73%, 7.82%, 3.82%, respectively. The three strains of lactic acid bacteria showed certain antioxidant activity.