《微生物学 Microbiology》课程PPT教学课件（英文版）environmental microbiology 1/3

Chapter 27,part A Environmental Microbiology

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings B.E Pruitt & Jane J. Stein Chapter 27, part A Environmental Microbiology

Metabolic Diversity Microbes live a variety of habitats because of their abilities: To use a variety of carbon energy sources To grow under different physical conditions Extremophiles live in extreme ·pH ·Temperature 。Salinity

Metabolic Diversity • Microbes live a variety of habitats because of their abilities: • To use a variety of carbon & energy sources • To grow under different physical conditions • Extremophiles live in extreme • pH • Temperature • Salinity

Mycorrhizae Fungi living in close association with plant roots Extend surface area of roots Plant cell wall Mycelia mantle Arbuscule Figure 27.1

• Fungi living in close association with plant roots • Extend surface area of roots Mycorrhizae Figure 27.1

Commercial Uses of Mycorrhizae Sliced truffle Figure 27.2

Commercial Uses of Mycorrhizae Figure 27.2

Biogeochemical Cycles Recycling (oxidation and reduction)of chemical elements

• Recycling (oxidation and reduction) of chemical elements Biogeochemical Cycles

The Carbon Cycle CO2 in atmosphere Burning Plants,algae, cyanobacteria Plant Animal Fixation respiration respiration Wood and fossil fuels Consumption CH4+CO2 Plants Animals Dissolved Decomposition C02 Photosynthesis Soil and Dead 介 water microbes organisms Aquatic Plants,algae, bacteria cyanobacteria 7 Fossil Dead organisms fuels cudingaquatic anim Figure 27.3

The Carbon Cycle Figure 27.3

The Nitrogen Cycle Free nitrogen gas (N2) (N2)in atmosphere Decomposition Nonsymbiotic 7 Protein Leguminous Azotobacter Industrial from plants Beljerinckia. fixation as dead cells 风 Cyanobacteria. fertilizer Clostridium 0 Fixation (N2O) Decay organisms (aerobic and anaerobic bacteria Symbiotic Denitrifying bacteria and fungi) Rhizobium (Pseudomonas, Bradyrhizobium Bacillus licheniformis. Assimilation Nitrites Ammonia Paracoccus (NO) Ammonification (NH3) denitrificans. Nitrosomonas and others) Key Denitrification Nitrates (NO3) Nitrites Nitrification Ammonification (NOS) Fixation Nitrification Nitrobacter Denitrification Figure 27.4

The Nitrogen Cycle Figure 27.4

Nitrogen Cycle Proteins and waste products Microbial decompositionAmino acids Amino acids (-NH2) Microbial ammonificaionAmmonia (NHa) Nitrosomonas Ammonium ion(NH4) →Nitrite ion(NO2） Nitrobacter Nitrite ion(NO2) Nitrate ion (NO3) Pseudmonas Nitrate ion (NO3 N2 Nitrogen-fixation N2 Ammonia(NH3)

Nitrogen Cycle N2 Nitrogen - fixation Ammonia (NH3 ) Nitrate ion (NO3 - ) Pseudmonas N2 Nitrite ion (NO2 - ) Nitrobacter Nitrate ion (NO3 - ) Ammonium ion (NH4 + ) Nitrosomonas Nitrite ion (NO2 - ) Amino acids (–NH2 ) Microbial ammonification Ammonia (NH3 ) Proteins and waste products Microbial decomposition Amino acids

Formation of a Root Nodule Pea plant Root Root hairs Nodules ①Rhizobia attach to root hair Rhizobia ④Enlarged root cells form a nodule Infection thread Bacteroids Bacteria change into An infection thread is formed, bacteroids;packed root through which bacteria enter cells enlarge root cells Figure 27.5

Formation of a Root Nodule Figure 27.5

The Sulfur Cycle Aerobic conditions Elemental sulfur Acid deposition H2S03 Beggiatoa, Thiobacillus 0 s02 Beggiatoa, Microbial Thiobacillus oxidation Burning of fossil fuels so Reduction by Desulfovibrio Assimilation by plants and bacteria SH sulfhydryl H2S groups of Decomposition proteins by microbes Purple and green (dissimilatory) phototrophic bacteria Purple and green phototrophic bacteria Anaerobic conditions (mostly soil and sediments) Elemental sulfur Figure 27.7

The Sulfur Cycle Figure 27.7