High performance liquid chromatography analysis, production and brief comparative study of citric acid producing microorganisms from spoiled onions in and around Vellore district

India is one of the largest producers of onion in the world producing over 13,920,000 metric tons. Storage is a major problem which leads to spoilage, and microbes play an important role in the spoilage. In this present study, biotechnologically important strains have been isolated from the spoiled onions by using appropriate enriched media. Two potential strains were isolated and a brief Comparative study was done for fungal and bacterial strains in terms of citric acid production and the production of citric acid was also checked by using the designed media named as PAPS. HPLC analysis was performed to confirm the presence of citric acid in the culture medium. Partial recovery was done by filtration and precipitating oxalic acid as calcium oxalate. Optimization was done for various physical and nutritional parameters such as carbon source, temperature, pH and incubation period in order to recover maximum amount of citric acid.