Biochemical Principles in Microbiology

Polysaccharides are referred to as glycans and have hundreds of monosaccharides all linked together. They are not water soluble and do not taste sweet. The main polysaccharides in nature include cellulose, glycogen, and starch. All are made from strings of glucose linked together in different ways. Glycogen is used for energy storage in bacteria and in animals. Starch is also used for energy storage in plants. Cellulose is a structural molecule used to make cell walls.

BIOCHEMICAL PRINCIPLES IN MICROBIOLOGY

The biochemistry of different microorganisms will be unique to the organism. For this reason, biochemical testing of bacteria can help to identify the bacterial species. There are some organisms that can be identified through their phenotype, while others must be identified by their genotype or by their different types of metabolism. There are, for example, different granules inside certain organisms that can be specific to the organism. An example is Pseudomonas aeruginosa, which will fluoresce under the microscope when their storage granules are stained with specific stains for their granules.

Another technique is to use biochemistry to identify lipid profiles. Their fatty acids can be unique to the organism. Biochemists can use fatty acid methyl ester analysis to detect the type of fatty acids in the cell membrane using gas chromatography. A related technique for identifying a bacterium is phospholipid-derived fatty acid analysis, which will look at the type of fatty acids in the bacterial cell wall.

Certain proteins can be unique to a microorganism so this can be used to identify the organism. The technique is called proteomic analysis, which breaks down the bacterial proteins and identifies the specific peptides that come from this using mass spectrometry. Glycoproteins can also be identifying features ot an organism. Antibodies can be made to attach to these glycoproteins in order to identify which glycoprotein is on the cell wall of the microorganisms. There are serological tests that can be done to identify streptococcus species by virtue of their specific carbohydrates on their cell wall.