华中农业大学：《食品微生物学》课程PPT教学课件（Food Microorganism）Chapter 7 Microbial Growth and Growth control

Chapter 7 Microbial Growth and Growth control 7.1 Overview of Cell Growth 7.2 Population Growth 7.3 Measurement of Growth 7.4 Continuous Culture: The Chemostat 7.5 Effect of Environment on Growth 7.6 Growth Control 7.7 Viral Control 7.8 Fungal Control

Chapter 7 Microbial Growth and Growth control 7.1 Overview of Cell Growth 7.2 Population Growth 7.3 Measurement of Growth 7.4 Continuous Culture: The Chemostat 7.5 Effect of Environment on Growth 7.6 Growth Control 7.7 Viral Control 7.8 Fungal Control

7.1 Overview of microbial growth The bacterial cell is a synthetic machine that is able to duplicate itself. The synthetic processes of bacterial cell growth involve as many as 2000 chemical reactions of a wide variety of types. Some of these reactions involve energy transformations. Other reactions involve biosynthesis of small molecules-the building, blocks of macromolecules-as well as the various cofactors and coenzymes needed for enzymatic reactions

7.1 Overview of microbial growth The bacterial cell is a synthetic machine that is able to duplicate itself. The synthetic processes of bacterial cell growth involve as many as 2000 chemical reactions of a wide variety of types. Some of these reactions involve energy transformations. Other reactions involve biosynthesis of small molecules-the building, blocks of macromolecules-as well as the various cofactors and coenzymes needed for enzymatic reactions

Binary Fission

Binary Fission

6 – 1. Microbial Nutrition • Nutrient requirements • Nutritional types of microorganisms • Uptake of Nutrients by the Cell • Culture Medium • Isolation of Pure Cultures

6 – 1. Microbial Nutrition • Nutrient requirements • Nutritional types of microorganisms • Uptake of Nutrients by the Cell • Culture Medium • Isolation of Pure Cultures

Microorganisms require about ten elements in large quantities, because they are used to construct carbohydrates, lipids, proteins, and nucleic acids. Several other elements are needed in very small amounts and are parts of enzymes and cofactors. Concepts: Nutrient requirements

Microorganisms require about ten elements in large quantities, because they are used to construct carbohydrates, lipids, proteins, and nucleic acids. Several other elements are needed in very small amounts and are parts of enzymes and cofactors. Concepts: Nutrient requirements

Macronutrients • 95% or more of cell dry weight is made up of a few major elements: carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorus, potassium, calcium, magnesium and iron. • The first six ( C, H, O, N, P and S) are components of carbonhadrates, lipids, proteins and nucleic acids

Macronutrients • 95% or more of cell dry weight is made up of a few major elements: carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorus, potassium, calcium, magnesium and iron. • The first six ( C, H, O, N, P and S) are components of carbonhadrates, lipids, proteins and nucleic acids

Trace Elements Microbes require very small amounts of other mineral elements, such as iron, copper, molybdenum, and zinc; these are referred to as trace elements. Most are essential for activity of certain enzymes, usually as cofactors

Trace Elements Microbes require very small amounts of other mineral elements, such as iron, copper, molybdenum, and zinc; these are referred to as trace elements. Most are essential for activity of certain enzymes, usually as cofactors

Growth Factors Amino acids are needed for protein synthesis, purines and pyrimidines for nucleic acid synthesis. Vitamins are small organic molecules that usually make up all or part enzyme cofactors, and only very small amounts are required for growth. (1)amino acids, (2) purines and pyrimidines, (3) vitamins

Growth Factors Amino acids are needed for protein synthesis, purines and pyrimidines for nucleic acid synthesis. Vitamins are small organic molecules that usually make up all or part enzyme cofactors, and only very small amounts are required for growth. (1)amino acids, (2) purines and pyrimidines, (3) vitamins

Major nutritional type Sources of energy, hydrogen/electrons, and carbon Representative microorganisms Photoautotroph (Photolithotroph) Light energy, inorganic hydrogen/electron(H/e- ) donor, CO2 carbon source Algae, Purple and green bacteria, Cyanobacteria Photoheterotroph (Photoorganotroph) Light energy, inorganic H/e- donor, Organic carbon source Purple nonsulfur bacteria, Green sulfur bacteria Chemoautotroph (Chemolithotroph) Chemical energy source (inorganic), Inorganic H/e￾donor, CO2 carbon source Sulfur-oxdizing bacteria, Hydrogen bacteria, Nitrifying bacteria Chemoheterotroph (Chenoorganotroph) Chemical energy source (organic), Organic H/e￾donor, Organic carbon source Most bacteria, fungi, protozoa Nutritional types of microorganisms

Major nutritional type Sources of energy, hydrogen/electrons, and carbon Representative microorganisms Photoautotroph (Photolithotroph) Light energy, inorganic hydrogen/electron(H/e- ) donor, CO2 carbon source Algae, Purple and green bacteria, Cyanobacteria Photoheterotroph (Photoorganotroph) Light energy, inorganic H/e- donor, Organic carbon source Purple nonsulfur bacteria, Green sulfur bacteria Chemoautotroph (Chemolithotroph) Chemical energy source (inorganic), Inorganic H/e￾donor, CO2 carbon source Sulfur-oxdizing bacteria, Hydrogen bacteria, Nitrifying bacteria Chemoheterotroph (Chenoorganotroph) Chemical energy source (organic), Organic H/e￾donor, Organic carbon source Most bacteria, fungi, protozoa Nutritional types of microorganisms

Algae, Cyanobacteria CO2 + H2O Light + Chlorophyll （CH2O） +O2 Purple and green bacteria CO2 + 2H2S Light + bacteriochlorophyll（CH2O） + H2O + 2S Purple nonsulfur bacteria (Rhodospirillum) CO2 + 2CH3CHOHCH3 Light + bacteriochlorophyll（CH2O） + H2O + 2CH3COCH3 Photoautotroph: Photoheterotroph:

Algae, Cyanobacteria CO2 + H2O Light + Chlorophyll （CH2O） +O2 Purple and green bacteria CO2 + 2H2S Light + bacteriochlorophyll（CH2O） + H2O + 2S Purple nonsulfur bacteria (Rhodospirillum) CO2 + 2CH3CHOHCH3 Light + bacteriochlorophyll（CH2O） + H2O + 2CH3COCH3 Photoautotroph: Photoheterotroph: