microbial metabolic pathways
DESCRIPTION
Primary Metabolic Pathways of MicroorganismsTRANSCRIPT
Metabolic Pathways
Primary Metabolic Pathways
• Catabolism
• Energy-generating metabolism
• Degradation mechanism
• Anabolism
• Energy utilizing pathway
• Biosynthetic
Catabolic Pathways
• Breakdown metabolism
• Substrate-level phosphorylation
• Products:
• ATP
• NADH
• NADPH
• FADH2
• heat
Embden-Meyerhoff-
Parnas Pathway
• Most common route
• Aerobic and anaerobic conditions
• Three key regulatory enzymes
Pentose Phosphate
(PP) Pathway
• Hexose Monophosphate Pathway
• Operates with EMP pathway
• Aerobic or anaerobic conditions
• Catabolic and anabolic roles
Entner–Doudoroff
(ED) pathway
• Used by few microbes lacking EMP
pathway
• G(-) bacteria
• Azotobacter, Pseudomonas, Rhizobium,
Xanthomonas and Zymomonas
Phosphoketolase (PK)
pathway
• Warburg–Dickens pathway
• Lactic acid bacteria (LAB)
• Heterolactic fermentation
Tricarboxylic acid
cycle (TCA)
• Aerobic conditions
• Further catabolism of pyruvate
Respiration
• Aerobic respiration
• Oxidative phosphorylation
• Chemiosmotic hypothesis
• Anaerobic respiration
• ETS as with aerobic respiration
Anaerobic Respiration
• Nitrate respiration
• Facultative anaerobes
• Redox potential:
• +0.42 : nitrate
• +0.82: oxygen
• Denitrification
• Nitrate → nitrite → nitrous oxide
• Pseudomonas, Paracoccus denitrificans and Thiobacillus denitrificans
Anaerobic Respiration
• Sulfate respiration
• Obligate anaerobes (Desulfovibrio sp.)
• Main product: H2S
• Carbonate respiration
• Archeans (Methanococcus and Methanobacterium)
• CO2+4H2→CH4+2H2O
Fermentation
Fermentation
Fermentation