Industrial Production of Xanthan Gum by Fermentation | Uses of Xanthan Gum:
What is xanthan Gum?
- Xanthan is a monospore polysaccharide produced by the fermentation of Xanthomonas campestris sp.
- Xanthan is also known as xanthan gum, xanthan polysaccharide, or industrial monosodium glutamate.
- It is a polysaccharide polymer compound composed of D-glucose, D-mannose, and D-glucuronic acid in a ratio of 2:2:1.
- The secondary structure of xanthan gum is that the side chains are reversely bound around the backbone of the main chain, and are maintained by hydrogen bonds to form a rod-like double helix structure.
- The tertiary structure of xanthan gum is a helical complex formed by weak non-polar covalent bonds between rod-shaped double helix structures.
- It has a variety of functions due to its special macromolecular structure and colloidal properties. ,
- Xanthan can be used as an emulsifier, stabilizer, gel thickener, film-forming agent, etc.
- Xanthan gum is a light yellow to white flowable powder with a slight odor.
- Xanthan is easily soluble in cold and hot water, neutral in solution, insoluble in ethanol, and resistant to freezing and thawing.
- Xanthan gum is a natural polysaccharide that was discovered by the U.S. Department of Agriculture’s Northern Regional Laboratory while researching how microbial polymers could be used in industry.
- Xanthan gum was first discovered by Allene Rosalind Jeanes in the 1950s at Northern Regional Center & became commercial in 1964.
Microorganisms used for xanthan Production:
- Different types of microorganisms have different abilities to produce xanthan. Therefore, different microorganisms can be used to produce xanthan products that people need.
- Today, xanthan fermentation technology plays a huge role in the food, Pharma, and Medical industry.
- To produce xanthan large number of microorganisms are used like bacteria.
- Xanthan is commercially produced by the bacterium Xanthomonas campestris, since 1964 fermentation.
- Xanthomonas campestris is a bacterial strain found on the leaves of brassica vegetables and can cause a variety of plant diseases such as black rot formation on broccoli, cauliflower, cabbage, and other leafy vegetables.
- This bacteria produces polysaccharides on the surface of the cell wall during its normal life cycle by a complex enzymatic process.
- The main advantages of using this microorganism are: that it is easier to obtain and easy to handle its ease of handling. It gives maximum yield and can ferment a variety of cheap raw materials like molasses and carbohydrates.
Process of Xanthan Production:
- Firstly the pure culture of the bacterium Xanthomonas campestris is produced as an aerobic submerged in the fermentation process by following steps.
- Select a culture medium containing carbon sources glucose, nitrogen source, and various trace elements.
- Sometimes in some industries, Corn syrup is chosen as the medium.
- The medium must contain a good amount of nutrition required by the bacteria for their growth and development.
- Now the medium is inoculated with Xanthomonas campestris species.
- The inoculated medium is transferred to a bioreactor. This is where the bacteria are incubated.
- In this sugary environment, the bacterium replicates rapidly and forms around trillion identical cells in 48 hours.
- After a few days, the bacteria used all the carbohydrates present in the medium/broth and produced a polysaccharide. This polysaccharide is called xanthan gum.
- When the final fermentation process is finished the broth is pasteurized to kill all the bacteria present in the broth & xanthan gum is recovered by precipitation with isopropyl alcohol.
- The recovered xanthan gum is then hydrated to remove water and is dried, milled, and finally packed.
- The xanthan gum is now ready to be sold for commercial use.
Uses of Xanthan Gum:
- It has a wide range of uses and wide coverage, from the food industry to oil recovery.
- Xanthan gum is an important stabilizer, used in more typical emulsifiers, it can prolong shelf life due to its unique pH stability.
- Xanthan gum is used in the preparation of meat fillings and sauces.
- Xanthan gum is often used in beauty products to keep lotion products separate.
- Xanthan gum also promotes water absorption in the skin and is used in different moisturizers.
- Xanthan gum is added to increase water-holding capacity, it can combine with starch, and inhibit starch aging.
- In toothpaste, xanthan gum is used as the suspension stabilizer and thickener of the paste.
Factors Affecting xanthan Production:
1. Temperature :
- The effect of temperature on xanthan production is numerous.
- The optimum temperature used for the production of xanthan by submerged fermentation of Xanthomonas campestris and other bacteria is between 30 to 33°C.
- Temperature can affect the growth of Xanthomonas campestris activity. In the optimum temperature range, as the temperature increases the growth and metabolism of the Xanthomonas campestris accelerate, and the rate of the fermentation reaction increases.
- When the temperature exceeds the optimal temperature range as the temperature rises the Xanthomonas campestris activity is quickly inactivated and the fermentation rate is reduced.
- Therefore, to ensure a normal fermentation process, it is necessary to maintain the optimum temperature.
2. pH :
- pH can affect the activity of microorganisms, enzymes, and fermentation rate.
- Based on the type of substrate and media and microorganisms the pH is vary.
- In defined media, the initial pH of the medium is usually adjusted to 7-8, while in the case of molasses, the pH must be neutral or slightly acidic.
- The pH of the medium is adjusted with NaOH, H2SO4, and HCl.
- In addition, pH will also affect the decomposition of nutrients in the medium. Therefore, the pH of the fermentation broth should be controlled.
3. Dissolved oxygen Concentration :
- The supply of oxygen is a key factor for aerobic fermentation and therefore it requires oxygen.
- Aeration and agitation meet the oxygen demand of a fermentation process of xanthan.
- Agitation is important for heat transfer, adequate mixing, and mass transfer.
- Aeration and agitation both maintain the homogeneous environment of culture by continuous mixing.
- Therefore, a large amount of oxygen must be continuously added to the fermentation broth, and stirring can increase the solubility of oxygen in the fermentation broth.
- The concentration of dissolved oxygen increased with the increase in the speed of agitation.
4. Concentration of nutrients :
- The concentration of various nutrients in the fermentation broth, especially the ratio of carbon to nitrogen, inorganic salts, and vitamins, will directly affect the growth of bacteria and the production of xanthan.