Research On Production And Process For Separation Of Itaconic Acid

As an important five-carbon binary unsaturated carboxylic acid,itaconic acid is widely used in pharmaceutical,textile,latex and other industries.At present,the production of itaconic acid mainly depends on chemical method and microbial method,but there are some problems in microbial fermentation,such as insufficient yield,tedious steps for separation of itaconic acid by crystallization,low separation efficiency and so on.In this study,firstly,the high-yield strain Aspergillus terreus CICC40205-4-56 was screened by pressure-mutagenesis method.The glucose of 80 g/L was fermented,and the yield of itaconic acid reached 34.3 g/L,which was 2.96 times higher than that of the original bacteria,and the strain had good stability.Secondly,based on the high-yield strains,the seed culture and fermentation culture were optimized in two stages.After the optimization of seed culture,the high-yield bacteria could form globules with controllable diameter(2-3 mm).And the output of itaconic acid increased by 5.96%compared with that before optimization.Combined with the response surface method to optimize the fermentation stage,the yield of itaconic acid increased by 9.27%,reaching 37.37 g/L.When the optimal process was applied to 5 L fermentor,the yield of itaconic acid reached 39.02 g/L.Finally,the process of adsorption and separation of itaconic acid by resin was studied.Through the analysis and comparison of the adsorption of itaconic acid by D301,D201,D318,D396,335 and 201 X 7 resins,it was found that D301 resin obtained the maximum adsorption capacity in pH=3,which was 113 mg/g;335 resin in pH=5,which was 140.75mg/g.The adsorption and desorption conditions of itaconic acid by the above two resins were optimized,and the desorption rates were 92.98%(D301 resin)and 87.5%(335 resin),respectively.On this basis,the adsorption and desorption conditions of itaconic acid by two kinds of resin in fixed bed were optimized,and the adsorption and desorption models of two kinds of resin column were established.Through the verification of the separation and desorption effect of itaconic acid in the fermentation broth,it is shown that the two fixed-bed separation models have a good fit,and the separation efficiency of itaconic acid is 85%,which is higher than that of crystallization(50%-80%).In this paper,from the point of view of strain selection and optimization of separation process of itaconic acid,a strain of Aspergillus terreus with better performance of producing itaconic acid was screened,and its optimal culture process was developed,and the process of separation of itaconic acid by ion exchange resin was studied.The model of resin column separation of itaconic acid was established,which laid a foundation for the development of efficient production and separation process of itaconic acid.