Aspergillus Efficiency Of Citric Acid Production

This thesis is a study of Aspergillus niger in sweet potato powder as raw material, fermentation medium, fermentation, to produce citric acid and screening of the strain producing acid selection of best condition, first to the lab experimental strains were separated and purified, inclined plane seed culture, bran expanding culture, finally in order to potato powder as raw material the fermentation medium for fermentation, by specifying the detection method to produce citric acid content determination, to test through screening and new strains of the acid producing ability, choose the acid producing ability of relatively high strain, and then the selected strains basis, repeat the above operation, thus picks the production ability of acid the largest strains.The second part of the experiment is to process some fermentation conditions for acid control, for example, temperature, time, pH value, oxygen, and the data analysis are discussed and the optimum reaction conditions.The experimental results show that in the second breeding strains acid production capacity than the first breeding to improve75.88%. the most suitable conditions should be fermentation solution pH between2.0-2.5, temperature of36, speed of220rpm, the fermentation period of48h, Aspergillus niger Producing Citric acid can reach the best efficiency.