Isolation Screening and Selection of Aspergillus Niger Cultures for Citric Acid Fermentation

The present study deal with the isolation, screening and selection of Aspergillus niger cultures for citric acid fermentation. The organism was isolated from onion and garlic peels which were collected from local market. Pour plate method using Czapak Dos Agar medium was used for isolation. The agar plates were incubated at room temperature for 7 days. Maximum sporulation were obtained and then stored in a refrigerator at 4°C for maintenance and further screening for citric acid...
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The present study deal with the isolation, screening and selection of Aspergillus niger cultures for citric acid fermentation. The organism was isolated from onion and garlic peels which were collected from local market. Pour plate method using Czapak Dos Agar medium was used for isolation. The agar plates were incubated at room temperature for 7 days. Maximum sporulation were obtained and then stored in a refrigerator at 4°C for maintenance and further screening for citric acid fermentation. The cultural conditions and nutritional requirements for citric acid production by the selected culture were optimized in 250 ml Erlenmeyer flasks by submerged mould culture technique prior to scale up studies in a stirred fermenter. Two types of fermentation were succeeded they are solid and submerged state fermentation. In solid state fermentation basal medium for citric acid production were prepared in 7 conical flasks of about 100 ml each containing 30 g of samples like wastes of apple, pineapple, carrot, beetroot, sugarcane, mosambi and grape and whereas in submerged state fermentation basal medium. The basal medium for citric acid production were prepared in 2 conical flask of about 100 ml each containing 15 ml of samples like date syrup and sugarcane juice were added in 2 conical flasks and 3.5 g of corn flour was also taken in separate flask containing the same amount of basal medium. These samples were then sterilized in an autoclave for 121°C for 15 lbs at 15 mins. These samples were cooled down and were inoculated with Aspergillus niger isolates which were obtained from Czapak Dos Agar medium. These flasks were then kept for incubation at room temperature for further studies. This comparative study of citric acid production in various medium were studied at each intervals up to 14 days of incubation. Pineapple and date syrup have shown an extreme citric acid production when compared to other samples.