第四节环境对微生物生长的 影响及微生物生长的测定
第四节 环境对微生物生长的 影响及微生物生长的测定
一、环境对微生物生长的影响 I温度 ⅡpH Ⅱ氧浓度
一、环境对微生物生长的影响 I 温度 II pH III 氧浓度
1温度 p嗜冷菌：Grows well at 0C;optimally between 0C -20°C p耐冷菌：Can grow at0-35C;optimum between 20-30°C ●嗜温菌：Optimum around20-45c ●嗜热菌：Optimum around55-65C 极端嗜热菌：Optimum around80-113C
I 温度 嗜冷菌: Grows well at 0ºC; optimally between 0ºC – 20ºC 耐冷菌: Can grow at 0 – 35ºC; optimum between 20 – 30ºC 嗜温菌: Optimum around 20 – 45ºC 嗜热菌: Optimum around 55 – 65 ºC 极端嗜热菌：Optimum around 80 – 113 ºC
Il pH 嗜酸菌 Grow optimally between pH 0 and 5.5 嗜中性菌 Growoptimally between pH 5.5 and 8 嗜碱菌 Grow optimally between pH 8-11.5
II pH 嗜酸菌 Grow optimally between pH 0 and 5.5 嗜中性菌 Growoptimally between pH 5.5 and 8 嗜碱菌 Grow optimally between pH 8 – 11.5
Ⅲ氧浓度 好氧的 微好氧菌 耐氧厌氧菌 图6-12氧与细菌生长的关系 严格好氧菌：Require oxygen for growth(~2O%) D兼性厌氧菌：Grow best in the presence of oxygen, but are able to grow(at reduced rates)in the absence of oxygen b名 微需氧菌：Require reduced concentrations of oxygen (~2-10%)for growth 耐氧厌氧菌：Can grow equally well in the presence or absence of oxygen 严格厌氧菌：Grow in the absence of oxygen;cannot grow in the presence of oxygen
III 氧浓度 严格好氧菌: Require oxygen for growth (~20%) 兼性厌氧菌: Grow best in the presence of oxygen, but are able to grow (at reduced rates) in the absence of oxygen 微需氧菌: Require reduced concentrations of oxygen (~2 – 10%) for growth 耐氧厌氧菌: Can grow equally well in the presence or absence of oxygen 严格厌氧菌: Grow in the absence of oxygen; cannot grow in the presence of oxygen
二、微生物生长的测定 微生物生长： 以单位时间里微生物数量或生物量 (Biomass)的变化来评价。 计数法 微生物生长的测定： 重量法 生理指标法
以单位时间里微生物数量或生物量 (Biomass)的变化来评价。 微生物生长: 二、微生物生长的测定 计数法 重量法 生理指标法 微生物生长的测定:
(一)计数法 1、直接计数法 Figure 6.19 Direct Grid with 25 large squares microscopic count of bacteria with a Petroff-Hausser cell Cover glass counter.The average number of cells within a large square Slide multiplied by a factor of 1,250,000 gives the number of bacteria per milliliter. Direct microscopic counts are useful for certain applications 缺点： 不能区分死菌与活菌； Microscopic count:All cells in several large squares are 不适于对运动细菌的计数： counted,and the numbers are averaged.The large square shown here has 14 bacterial cells 需要相对高的细胞浓度； The volume of fluid over the large square is 1/1.250.000 of a milliliter.If it contains 14 个体小的细菌在显微镜下难以观察。 cells,as shown here,then there are 14 times 1.250,000 (17.500,000)cells in a milliliter
细菌、孢子、酵母菌 1、直接计数法 缺点: 不能区分死菌与活菌; 不适于对运动细菌的计数; 需要相对高的细胞浓度; 个体小的细菌在显微镜下难以观察。 (一) 计数法
2、平板计数法 1 ml 1 ml 1 ml 1ml 1.ml Original 9 ml broth inoculum in each tube Dilutions 110 1:100 1:1000 110.000 1:100.000 Plating 1:10 1:100 1:1000 1:10,000 1100.000 Calculation:Number of colonies on plate x reciprocal of dilution of sample number of bacteria/ml (For example,if 32 colonies were on a plate of /1000 dilution,then the count is 32 x 10,000 =320,000/ml in sample
2、平板计数法
(a)The pour plate method (b)The spread plate method Figure 6.16 Methods of preparing plates for plate counts. 1.0 or 0.1 ml 0.1ml How do plates diff 样品充分混匀； Inoculate ①Inoculate plate empty plate containing solid medium Bacterial dilution 每支移液管及涂布棒只能 接触一个稀释度的菌液； Add melted hutrient aga ②Spread ino over surfac 同一稀释度三个以上重 evenly Swirl to mix 复，取平均值； 每个平板上的菌落数目合 Colonies 适，便于准确计数； grow in and only on solidified of medium medium
样品充分混匀； 每支移液管及涂布棒只能 接触一个稀释度的菌液； 同一稀释度三个以上重 复,取平均值； 每个平板上的菌落数目合 适，便于准确计数；
菌落形成单位(colony forming units,CFU)
菌落形成单位(colony forming units, CFU)