Microbial Metabolism

Objectives:

35. Explain how lipid and protein catabolism can be integrated with carbohydrate metabolism.

36. Define beta-oxidation and explain what it does.

Lipid and Protein Catabolism

 

Lipases hydrolyze lipids into glycerol and fatty acids.

 

Fatty acids and other hydrocarbons are catabolized by beta oxidation.

 

Beta oxidation produces two carbon units that are linked to CoA to make acetyl-CoA.

 

Catabolic products can be further broken down in glycolysis and the Krebs cycle.

 

 

 


 

 

Before amino acids can be catabolized, they must be converted to various substances that enter the Krebs cycle or glycolysis.

 

Transamination (transfer of NH2), decarboxylation (removal of COOH), and dehydrogenation (H2) reactions convert the amino acids to be catabolized into substances that enter the glycolytic pathway or Krebs cycle.

 

 

 

Biochemical Tests and Bacterial Identification

 

Bacteria and yeast can be identified by detecting action of their enzymes.

 

 

Acid production on the left from fermentation of glucose,
alkaline end products from protein degradation on the right

Fermentation tests are used to determine whether
an organism can ferment a carbohydrate to produce acid and gas