Construction of Lactobacillus acidophilus expression vector and expression of mannanase
In order to obtain mannanase-producing Lactobacillus acidophilus strain,the mannanase expression vector was constructed and transformed into L.acidophilus.The enzymatic properties of mannanase produced by recombinant L.acidophilus were analyzed,and the acid resistance of recom-binant L.acidophilus and anti-protease activity of mannanase were determined.The results showed that the mannanase activity produced by recombi-nant L.acidophilus was 353 U/ml after fermentation for 24 h.The optimum catalytic pH and temperature of mannanase was 5.5 and 55 ℃,respectively.The recombinant L.acidophilus had certain acid resistance at pH 2.0 to 4.5,and the survival rate was 77.3％at pH 2.0 for 2 h.After mannanase solu-tion was treated with pepsin and trypsin for 160 min,the relative activities of mannanase were 65％and 28％,respectively.The results indicated that the mannanase had certain anti-pepsin and partial anti-trypsin degradation ability.
NETL
NSTL
万方数据
维普
