傣家酸鱼中乳酸菌的分离鉴定及乳酸发酵的初步研究

Research on lactic acid fermentation of lactic acid bacteria isolated from the sour fish (Suan yu) made by Dai people families

为获得新来源的乳酸发酵菌株,以采自云南省德宏州的3份传统傣家酸鱼为供试样品,分离纯化菌株。通过Ca CO3-溴甲酚紫产酸平板、摇瓶发酵、色谱分析等手段筛选出产乳酸菌株。采用传统分类方法结合16S r DNA序列分析方法,对产乳酸菌株进行鉴定并保藏,并用EDTA定钙法研究了菌株的乳酸产量。结果表明,从3份传统傣家酸鱼中分离到10个菌株,筛选出乳酸发酵菌株sy1、sy3、sy4,色谱分析表明,3株菌的发酵产物均为乳酸。采用传统分类方法结合16S r DNA序列分析方法,确定3株菌均为植物乳杆菌。3株菌均能迅速产酸,能在p H 3.5以下生长;在初始葡萄糖浓度为100 g/L的培养基中发酵72 h,测得菌株sy1、sy3、sy4乳酸产量分别为66、76和69 g/L,表明3株菌均有较好的乳酸发酵能力,可作为乳酸发酵的出发菌株进行进一步研究。

In order to explore new lactic acid bacteria resource for lactic acid fermentation, strains were isolated from 3 samples of traditionally fermented sour fish made by Dai people in the Prefecture of De Hong. Lactic acid bac- teria were screened from them by CaCO3-bromocresol purple plate, shaking flask fermentation and chromatographic a- nalysis, and identified by 16S rDNA sequencing analysis along with conventional identification. The properties of the strains for lactic acid production were also studied. The results showed that, 10 strains were isolated from 3 samples and strains syl, sy3 and sy4 could produce lactic acid confirmed by chromatographic analysis. All these 3 strains be- longed to Lactobacillus plautarum according to 16S rDNA sequencing analysis along with conventional identification. Primary fermentation showed that all these 3 strains could produce lactic acid quickly and live below pH 3.5. Further- more, results showed that after 72 h of fermentation, lactic acid production was 66 g/L for strain syl, 76 g/L for strain sy3 and 69 g/L for strain sy4 when initial substrate concentration was 100 g/L. Those work showed that these 3 strains were excellent as original stains for lactic acid fermentation.