普通生物学课件_第七章_微生物的生长与控制.ppt

星空8538的个人中心 一些细菌的代时 菌名 培养基 培养温度 代时 E. coli（大肠杆菌） 肉汤 37℃ 17min E. coli 牛奶 37 12.5 Enterobacter aerogenes（产气肠细菌） 肉汤或牛奶 37 16~18 E. aerogenes 组合 37 29~44 B. Cereus（蜡状芽孢杆菌） 肉汤 30 18 B. thermophilus（嗜热芽孢杆菌） 肉汤 55 18.3 Lactobacillus acidophilus（嗜酸乳杆菌） 牛奶 37 66~87 Streptococcus lactis（乳酸链球菌） 牛奶 37 26 S. lactis 乳糖肉汤 37 48 Salmonella typhi（伤寒沙门氏菌） 肉汤 37 23.5 Azotobacter chroococcum（褐球固氮菌） 葡萄糖 25 344~46 Mycobacterium tuberculosis（结核分枝杆菌）组合 37 792~93 Nitrobacter agilis（活跃硝化杆菌） 组合 27 1200 不同温度下的代时 温度对微生物的代时有明显影响： E. Coli 在不同温度下的代时 温度（℃） 代时（分） 温度（℃） 代时（分） 10 860 35 22 15 120 37 17 20 90 40 17.5 25 40 45 20 30 29 47.5 77 典型的生长曲线 （Growth curve） 营养物浓度与对数期生长速率和产量 作用方式：影响微生物的生长速率和总生长量 生长限制因子：凡是处于较低浓度范围内，可影响生长速率和菌体产量的营养物就称生长限制因子 对数期（logarithmic phase） 应用意义 （１）是代谢生理研究的良好材料 （２）增殖噬菌体的最适宿主菌龄，生产中接种的最佳种龄 由于此时期的菌种比较健壮，生产上常用该时期的菌体作为菌种。另外，实验室常用对数期的菌种作为实验材料研究微生物的代谢、遗传研究或进行染色、形态观察等。 3. Stationary Phase. Exponential growth cannot be continued forever in a batch culture (e.g. a closed system such as a test tube or flask). Population growth is limited by one of three factors: 1. exhaustion of available nutrients; 2. accumulation of inhibitory metabolites or end products; 3. exhaustion of space, in this case called a lack of biological space. During the stationary phase, if viable cells are being counted, it cannot be determined whether some cells are dying and an equal number of cells are dividing, or the population of cells has simply stopped growing and dividing. The stationary phase, like the lag phase, is not necessarily a period of quiescence. Bacteria that produce secondary metabolites, such as antibiotics, do so during the stationary phase of the growth cycle (Secondary metabolites are defined as metabolites produced after the active stage of growth). It si during the stationary phase that spore-forming bacteria have to induce or unmask the activity of dozens of genes that may be involved in sporulati