苯丙氨酸脱氨酶发酵工艺及其酶学性质研究

选育出一株具有较高苯丙氨酸脱氨酶活性的菌株巨大芽孢杆菌AS1.127-NJU10。考察了该菌的发酵产酶条件,结果表明:蔗糖为最佳碳源、酵母浸膏和NH4C l组成最佳氮源,其质量浓度分别为:ρ(蔗糖)=20 g/L,ρ(酵母浸膏)=2 g/L和ρ(NH4C l)=10 g/L;发酵培养基最适pH=6.5,培养温度为37℃;诱导物ρ(L-苯丙氨酸)=1 g/L时,酶活最高达1 070 U。同时对苯丙氨酸脱氨酶的性质进行了研究,结果表明:该酶最适pH=5.8,最适温度为40℃,反应液中添加φ(吐温-80)=0.2%和c(K+)=10-5mol/L能明显提高酶活。

Study of Fermentation and Properties of Phenylalanine Deaminase

The strain of Bacillus magterium AS1.127-NJU10 was firstly selected with high phenylalanine deaminase activity.Fermentation conditions for phenylalanine deaminase were studied.The result showed that,20 g/L saccharose was the best carbon sources,2 g/L yeast extract and 10 g/L NH_4Cl were the best nitrogen sources,the optimal temperature and the initial pH of the culture medium for enzyme production were 37 ℃ and 6.5 respectively,and the concentration of inducer L-phenylalanine was 1 g/L.The highest enzyme activity of(1 070)U was achieved under these optimal conditions.In addition,the properties of deaminase were studied,the optimal temperature and pH being 40 ℃ and 5.8 respectively.Enzyme activity was remarkably enhanced in the presence of volume frection 0.2% Tween-80 and 10~(-5) mol/L K~+.