Fermentation of citric acid is one of the largest biotechnology industries. Studies have also proved that Aspergillus Niger is the most operational strain for citric acid production by fermentation of carbohydrates by secretion of huge amounts of enzymes in the environment. Citric acid is widely used in food and beverage industry, healthcare and industrial applications. There is a huge demand for citric acid due to its varied applications across different industries. The report studies one of the process of production of citric acid along with implementation of the strain. Also, the document studies various methods for obtaining the strain for industrial production of citric acid.

Citric acid is an important organic acid that is produced by various fermentation processes. Citric acid is available in large quantities in most of the plants and animals. Citric acid is commercially produced since years and can be traced back to the early 1900s. Some applications of citric acid are food, chemicals and pharmaceutical industries and is majorly used as an acidulant. It is further used in additive detergents, cosmetics and toiletries. Citric acid fermentation is one of the biggest biotechnological industries and the same has been proved that the strain i.e. Aspergillus niger provides the best result. This is due to fermentation of carbohydrates via huge number of enzymes in the environment for reducing carbon sources into small sugar molecules that are further used as nutrients. Currently the region of China contributes maximum share in the citric acid industry. However, China has been facing challenges in the field of biotechnology fermentation.

The output depends on the quality of strains used during the production process. A unique method currently being used is the mutagenesis technique, wherein heavy ion irradiation leads to new breeding of new mutants and creating a wider range of mutation types due to greater relative biological effect (RBE).

The process

A parental strain was maintained on potato-dextrose agar slants and stored at the reduced temperature of 4 degree. Carbon ion irradiation produced H4002, H1, H3, H4 and H5 and further XHW2 and XHW3 components were obtained after x-ray irradiation. Fermentation was further done in a 50-L stirred tank reactor prepared with the source of carbohydrates. Corn meal was hydrolyzed by alpha amylase at a temperature of 60-72 degree centigrade for 30 minutes and in a bio reactor of 50 liter capacity. After centrifugal filtration a supernatant was obtained which after dilution with water produces sugar concentration. This was further autoclaved for 30 minutes at the temperature of 118 degree centigrade. Amount of Citric acid was calculated by titration, sodium hydroxide with phenolphthalein as the pointer. Total amount of sugar was hydrolyzed at the high temperature for a period of 10 minutes with glucose and fructose and then analyzed with the help of Fehling reagent. Further calculations of a dry cell mass was done after washing with tap water and drying it for 5 minutes. These steps are repeated 2-3 number of times to achieve the desired results.

How Corn Meal Hydrolysate helps in Citric acid conversion.

A 50-Litre bioreactor was used to product citric acid for large industrial application with the help of mutant H4002. The good physical parameters of mutant H4002 i.e. dissolving in oxygen has helped in production of citric acid. At the same time the concentration and type of carbon source is the most important parameter for production of better quality citric acid.

In optimized culture condition (data not shown), wherein the basic concentration of sugar is increased from (200±0.0) to (235.7±2.4) g/L, the resultant production of citric acid also increases from (177.7±3) to (196±0.0) g/L after 60 h fermentation. Furthermore, citric acid produced was for 2.96 and 3.27 g/(L.h) this further resulted in reduction of sugar concentration to 26.7±0.7 with a conversion rate of approximately 83% -88%. The initial sugar concentration reached 210 g/L with a mutant H4002 demonstrating the accumulation of best citric acid that too with a high productivity and conversion rate of 89.25% and a lower residual concentration of sugar.

Furthermore, the fermentation process resulted in round shaped and compact pellets were observed that improved overall properties of the process and improved the citric acid production. The various features of citric acid that is converted from various concentrations are, the amount of sugar consumed in the fermentation process. The amount of citric acid that is produced during the fermentation process and conversion rates and productivity.

The production of citric acid is influenced by the cost effectiveness of the process, low cost raw-material is important to establish a cost-effective technology. Various types of feedstock has been used and studied to find the best and cost-effective technology but have failed to provide the desired results. It has been proved that when citric acid is produced with a mutant H4002; it is more cost effective and has a larger output. Also, there is extensive research and development happening in the industry to further enhance the output received.

Final Conclusion

To achieve the mutants that can be used for large volumes of hyper citric acid fabrication, use of faster carbon ions and X-rays for induction of mutagenesis of A.niger. Once the isolation is processed, a mutant is produced and is called as H4002, with improved citric acid production which was received from carbon ion irradiation. Bulk production of citric acid in a cost-effective manner is useful as it further influences the market applications.

Citric acid is used in various industries like food and beverages and healthcare industry. In the food and beverage industry citric acid is used as a flavor enhancer and sweetener in various products. The demand for processed food is growing tremendously due to the growing population and disposable income. The growing population is favoring processed food and ready to eat food items. Similarly, the beverage industry also uses citric acid as a flavor enhancer. To meet the increasing demands across various industries, need for a cost-effective bulk production process is there. This need is fulfilled by the use of mutant H4002 extracted with the help of corn meal.