Expression of phytase gene in Lactobacillus acidophilus
Phytase and Lactobacillus acidophilus are important feed additives.In order to obtain L.acidophilus strain producing phytase,the phytase gene of Escherichia coli was cloned,the expression vector was constructed and transformed into L.acidophilus.The recombinant L.acidophilus was fermented to produce enzyme and the enzymatic properties of the enzyme solution were determined.The acid resistance of the recombinant L.acidophilus and the anti-protease activity of the phytase solution were further studied.The results showed that the phytase activity of recombinant L.acidophilus was 984 U/mL after fermentation for 24 h.The optimum catalytic pH was 4.5 and the optimum catalytic temperature was 60 ℃.The recombinant L.acidophilus had certain acid resistance at pH 2.0～4.5,and the survival rate was 76.4％at pH 2.0 for 2 h.The phytase solution remained 85％of the relative enzyme activity after 160 min of pepsin treatment,and 29％of the relative enzyme activity after 160 min of trypsin treatment.These results provide an important basis for the subsequent application of recombinant L.acidophilus.
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维普
