Carbohydrates as culture media additives in Microbiology


Carbohydrates, also known as saccharides, are a predominant class of biological molecules consisting of repeating sugar units. They are chemically classified into monosaccharaides, oligosaccharides and polysaccharides according to the number of individual units. Carbohydrates are principally applied in microbiology as an essential additive of culture media. Carbohydrates supplementation of microbiological culture increases the overall growth rates and the biomass production over time. Bearing carbon and hydrogen backbone, carbohydrates are an indispensable energy source for microbial growth and metabolism.

Glucose, a simple monosaccharide, is prevalently utilized by microorganisms in energy synthesis, because most microorganisms possess the enzymes required for the degradation and oxidation of this sugar. Some microorganisms possess enzymes to break down complex carbohydrates like disaccharides (sucrose or lactose) or polysaccharides (starch). For example, lactose is a disaccharide comprising of glucose and galactose units bridged by a glycosidic bond. Bacteria that utilize lactose as energy source must produce an enzyme called lactase to break glycosidic bond. Similarly starch is catabolized by α-amylase generating free glucose monomers.
Glucose is known as key energy-storing molecule, which is readily metabolized by cellular machinery to perform the tasks such as growth, maintenance and reproduction. Glycolysis is a metabolic pathway that degrades glucose producing high-energy molecules (ATPs), and another important organic molecule, pyruvate. Aerobic microorganisms, which have ability to survive in an oxygenated environment, synthesize chemical energy from pyruvate through cellular respiration. Alternatively, anaerobic microorganisms produce limited amount of energy in deoxygenated environment by the process of fermentation. However, glucose concentration above an optimal level can decline cell growth by inhibiting vital enzymes. Therefore, depending upon microbial strain, defined concentration of a particular carbon source is requisite for cultivation of microorganisms.

Related products:


C-2600   D-Cellobiose
A glycosylglucose consisting of two glucose units linked via a beta (1->4) bond. Used in culture medium to differentiate bacteria on the basis of carbohydrate fermentation abilities.

Cat.No. - Product name
A-8270    D-Arabitol
A-8280    L-Arabitol
A-8200    D-Arabinose
A-8240    L-Arabinose   
F-8060    L-Fucose
M-0955    Maltotriose
M-1000    D-Mannose    
M-1520    D-Melezitose, monohydrate    
M-1700    D-Melibiose monohydrate    

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