Lactobacillus brevis D-tag1产L-阿拉伯糖异构酶的条件优化

Optimization production of L-arabinose isomerase by Lactobacillus brevis D-tag1

为实现D-塔格糖的安全生产,筛选获得了一株产L-阿拉伯糖异构酶的短乳杆菌Lactobacillus brevis D-tag1。以菌体生长量和产酶量为依据,对碳源、氮源、发酵温度和发酵初始pH进行优化,提高其产酶能力。结果表明,采用优化后的发酵培养条件,在初始pH 6.0、发酵温度37℃、发酵时间24 h的最适条件下,菌体产酶活力为6.8 U/mL,是优化前的近2.3倍。以质量分数9.0%的D-半乳糖为底物,在pH 7.0、55℃、全细胞催化反应48 h,D-半乳糖生成D-塔格糖的转化率为43%~44%。

To realize the safe production of D-tagatose,a strain can produce L-arabinose isomerase was obtained by screening and identified as Lactobacillus brevis D-tag1.The carbon source,nitrogen source,fermentation temperature and initial pH of fermentation were optimized to improve the enzyme production capacity.The results showed that at the optimal conditions of initial pH 6.0,fermentation temperature 37℃and fermentation time 24 h,the enzyme activity could reach to 6.8 U/mL,nearly 2.3 times of that before optimization.Using 9.0%D-galactose as substrate,the conversion of D-galactose to D-tagatose was 43%to 44%at pH 7.0,55℃,after 48 h of whole cell catalytic reaction.