Abstract:  Using Diasporangium sp. A1.13 as original strain, the protoplast mutagenesis by UV, microwave and DES were carried on in order to enhance the arachidonic acid yield. The mutant MW40+DES20 II-4 was selected through low temperature (15 ℃) and aspirin (0.12 kg/ml) as inhibitors with the result of the AA content in total fatty acids increasing from 8.034% to 15.098%. Fermentation experiment was carried on 5 L fermentation equipment. Results showed that the biomass, arachidonic acid yield and fatty acid yield reaches 12.252 g/L, 4.307 g/L and 604.557 mg/L respectively increasing 24.96%, 56.39% and 193.924% than the initial strain. It is thought that it is an effective breeding means for fungus producing fatty acids through analysis the fatty acid component of the mutants.

Key words: arachidonic acid, Diasporangium sp., protoplast, mutation breeding