文档介绍：摘要
从土壤中筛选出一株产β-半乳糖苷酶的枯草芽孢杆菌,并对菌株和其产生的β-半乳糖苷酶进行了测定。单菌落的最佳生长时间是10h,%,最佳培养时间24h;该菌株产生的β-,最适生长温度为37℃,酶的稳定性较高,4h后相对酶活仍能维持85%以上;Mg2+对酶活性的促进作用最强,当浓度为10 mmol/L时,%,Cu2+对酶活性抑制作用最强,少量Cu2+(1mmol/L)就可使酶失活。
本实验还进行了β-半乳糖苷酶的固定化实验。以海藻酸钠为栽体、戊二醛为交联剂,对乳糖酶进行固定化。研究了海藻酸钠浓度、***化钙浓度、戊二醛浓度、固定化时间对酶固定化的影响,并对固定化酶酶促反应的最适pH、温度等进行了测定。结果表明,4%的海藻酸钠,在温度37℃、pH6~7、***化钙浓度1%、%下对乳糖酶的固定化率最高。酶促反应特性测定结果表明,固定化后乳糖酶的稳定性增强,最适温度范围较非固定化乳糖酶大,最适pH范围与非固定化乳糖酶大致相同。但固定化酶珠体机械强度较差,尚待改进。
关键词:β-半乳糖苷酶酶活性酶的固定化
Absract
A strain isolated from soil in producing β-galactosidase of Bacillus subtilis, and strains and β-galactosidase were measured which produces. A single colony of the best growth time is 10h, the best inoculum was %, the best culture time 24h; optimum pH β-galactosidase enzyme produced by this strain is , the optimum temperature is 37℃, enzyme high stability, 4h after the relative activity can be maintained above 85%; Mg2+ on the activity of promoting the strongest, when the concentration of 10 mmol/L, the enzyme activity of up to %, Cu2+ inhibition of enzyme activity most, a small amount of Cu2+ (1mmol/L) can inactivate the enzyme.
The experiments were also β-galactosidase immobilization experiments. The lactase was immobilized on sodium alginate carrier by cross-link with glutaraldehyde. The effects of flutaraldehyde concentration, amount of the enzyme and temperature immobilization were analyzed. The reaction conditions (optimun pH and temperature) of the immobilized lactase were studied. The results show that the high recovery rate of immobilized enzyme could be obtained under the conditions of % glutaraldegyde, 4% sodium alginate and 37℃ temperature.
Keyword: β-galactosidase, enzymes activity, Immobilization of enzyme
目录
摘要 I
Absract II
目录 III
第1章绪论 1
研究背景 1
课题研究目的和意义 2
国内外研究现状和发展趋势 2
β-半乳糖苷酶的来源及其特性 4
细菌产生的β-半乳糖苷酶 4
酵母菌产生的β-半乳糖苷酶 4
霉菌产生的β-半乳糖苷酶 4
β-半乳糖苷酶在食品工业中的应用 5
水解牛乳和其它乳制品中的乳糖 5
生产低