Suppressing method of iso-citric acid formation in producing citric acid from hydrocarbons by fermentation

摘要

The present invention relates to a suppressing method of iso-citric acid formation in producing citric acid from hydrocarbons by fermentation. This process is carried out by culturing the microorganisms selected from the group belonging to Candida tropicalis, Candida lipolytica, Candida intermedia and Candida brumptii and their mutants and variants in the culture medium containing paraffinic and olefinic hydrocarbons and their mixture as carbon source under aerobic conditions, wherein specific non-ionic surface active agent is added to said culture medium. The specific non-ionic surface active agent added to said culture medium is selected from the group of sorbitan fatty acid esters and polyoxy-ethylene sorbitan fatty acid esters. The amount of specific surface active agent added to said culture medium is enough from 0.005 to 0.5 percent by weight, preferably from 0.02 to 0.2 percent on the weight basis of said culture medium.