酒醅中乳酸菌的分离鉴定及性能研究

Isolation, Identification and Properties of Lactic Acid Bacteria in Fermented Grains

为探究酒醅中乳酸菌的性能,本研究采用稀释涂布平板法筛选分离出1株乳酸菌,对此菌株进行生理特性、发酵特性以及不同环境下的生长代谢研究。结果表明,经16S rDNA鉴定得出此株乳酸菌为Limosilactobacillus fermentum,命名为L.fermentum B17,L.fermentum B17产乳酸量可达8.4 g/L;B17可耐受6%盐浓度,10%vol乙醇浓度,50℃温度;液态发酵结果表明,L.fermentum B17和S.cerevisiae C6共培养可促进L.fermentum B17的生长,相比于单菌发酵乳酸含量显著提高,由2.32 g/L增加到6.24 g/L,L.fermentum B17抑制S.cerevisiae C6生长,乙醇含量由S.cerevisiae C6单菌发酵时的21.62 g/L下降到18.84 g/L;模拟白酒不同环境条件的研究下,使用酒醅浸提液作为培养基,结果表明额外添加乳酸、乙酸均会抑制L.fermentum B17生长和乳酸代谢,额外添加乙醇可促进L.fermentum B17生长,L.fermentum B17在温度为42℃和47℃时生长活性较强。

To explore the performance of lactic acid bacteria in fermented grains,a strain of lactic acid bacteria was isolated.The physiological characteristics,fermentation properties,and growth and metabolism of the strain under different conditions were studied.Based on 16S rDNA identification,the strain was identified as Limosilactobacillus fermentum,and named L.fermentum B17.The yield of lactic acid of L.fermentum B17 reached up to 8.4 g/L.L.fermentum B17 could tolerate 6%salt,10%ethanol,and 50℃.The results of liquid-state fermentation showed that co-culture of L.fermentum B17 and S.cerevisiae C6 promoted the growth of L.fermentum B17,and significantly increased the lactic acid content(from 2.32 g/L to 6.24 g/L)compared with single-strain fermentation.L.fermentum B17 inhibited the growth of S.cerevisiae C6,reducing the ethanol content from 21.62 g/L in single-strain fermentation to 18.84 g/L.The results of the study on different environmental conditions showed that the addition of lactic acid and acetic acid inhibited the growth and lactic acid metabolism of L.fermentum B17.In contrast,the addition of ethanol promoted the growth of L.fermentum B17.L.fermentum B17 exhibited stronger growth activity at temperatures of 42℃and 47℃.