Microorganisms are used in the production of organic acid and also biopolymers. These products have changed our life. Microorganisms are used in industrial microbiology techniques to produce important pharmaceutical compounds, food additives, biofuels, agricultural products and much more.

Organic Acids:

Production of organic acids using microorganisms is very important in industrial microbiology. This also illustrates the effect of trace metal concentration and organic acid balance and excretion. Organic acids such as citric acid, acetic acid, lactic acid, fumaric acid and glutamic acid are important products.

Citric Acid:

Today most of the citric acid is produced using microorganisms. Major portion of this is used in food industry and beverage industry. Small percent of citric acid is also used in pharmaceutical industry.

The citric acid fermentation technique involves limiting the concentration of trace metals such as manganese and also iron, this stops growth of pergillus niger at required point in the fermentation process. Low concentration of trace metals are controlled by using ion exchange resins. Citric acid fermentation was used to be carried out as static surface growth, but now it is done in aerobic stirred fermenters. In the fermentation media sugar is used in very high concentration and copper metal counteracts the inhibition effect of iron on citric acid production. The success of this fermentation process depends on the functioning and regulation of the pathways such as glycolytic and the tricarboxylic acid cycle. After the growth phase, citrate synthase enzyme activity increases and decreases the activities of aconitase and isocitrate dehydrogenase enzyme. This in turn helps in citric acid accumulation and excretion by the microorganisms.

Gluconic Acid:

Gluconic acid synthesis is done by using microorganism known as Aspergillus niger. Gluconic acid production is done by a single enzyme called as glucose oxidase. Aspergillus niger is grown in a fermentation medium known as corn-steep liquor medium, under optimum conditions. Nitrogen acts as growth limiting factor and this transforms the resting microbial cells to transform the remaining glucose to gluconic acid, this occurs in a single step reaction. Gluconic acid is used in detergent industry and also used as calcium and iron carriers.

Specialty Compounds for Use in Medicine and Health:

Other than antibiotics and amino acids, microorganisms are also used in producing other special compounds, which can be used in medicine and health care industry. These speciality compounds include sex hormones, antitumor agents, ionophores, and also other compounds that can be used in agriculture industry, to prevent the bacterial, fungal infection.


Microorganisms are also used in the production of polymers known as biopolymers. These biopolymers are used as gelling agent and also to modify the flow characteristics of liquids. These biopolymers are used in pharmaceutical industry and also in food industry. Using microorganisms for the production of biopolymers has got a major advantage that is the production is independent of climate changes, which can limit the availability of raw materials.

Some of the examples for biopolymers include dextrans, polyesters, cellulose microfibrils, polysaccharides such as scleroglucan, xanthan and much more.

1. Dextrans are used as absorbents and also as blood expanders.

2. Polyesters are produced using microorganism Pseudomonas oleovorans are used in the production of speciality plastics.

3. Cellulose microfibrils are produced using microorganism Acetobacter strain, and are used in food industry as food thickening agents.

4. Scleroglucan polysaccharide is used in the oil industry as drilling mud additives.

5. Xanthan polymer is produced using microorganism Xanthomonas campestris, which are used in oil recovery enhancer.

6. Cyclodextrins can be used in a variety of industries, because of its molecular structure. For example cyclodextrins are used in pharmaceutical industry, as solubility enhancer, to remove chemical door and also they are used to reduce their bitterness.

7. Cyclodextrins are also used as selective adsorbents. For example they are used to remove cholesterol from egg and butter.

8. Cyclodextrins are used to protect species from oxidation.


In all cases, it is very important to synthesis and recover the microbial products such as biopolymers or organic acid or any other compounds such as antibiotics under controlled conditions, so that all the biological activities of these compounds are retained and they reach the consumer in a effective and also stable conditions.

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