Studies On The Technology Of Itaconic Acid Production By Aspergillus Terreus

As the Itaconic Acid has a special chemical structure,which has determined that its chemical properties were very lively,so it can occur addition,polymerization and other chemical reactions with other molecular.Itaconic acid is a intermediate of chemical synthesis,and has a good extensive application prospect,which applied to the chemical industry,medicine,agriculture and other fields.It was known as the jewel in the crown in the field of organic acids.In order to enhance Itaconic Acid production by Aspergillus terreus TN-474 fermentation,the fermentation medium components and fermentation conditions of Itaconic Acid were investigated.On the base of the optimized medium and optimized culture conditions in shake flask,the culture conditions of 50L fermentor were optimized,and the results of this paper are as following:The effects of fermentation conditions on the production of Itaconic Acid by Asp.terreus TN-474 were studied in consideration detail.In the medium composition aspects,the results indicated as following:NH₄NO₃,as the main nitrogen source,had little effect on the fermentation,but dried corn steep liquor powder,as the auxiliary nitrogen source,was significantly affect to the fermentation.The element of Phosphorus was beneficial to glucose metabolism and could promote cell growth., through the experiments,it was found that KH₂PO₄ has a greater impact on Itaconic Acid fermentation.It was also found that the addition of MgSO₄·7H₂O could stimulate the growth of mycelia and Itaconic Acid production,CuSO₄·5H₂O could promote Itaconic Acid production.In the culture conditions aspects,the initial pH, temperature,inoculation amount,and liquid volume in flask were determined and studied,which to lay a foundation for optimization experiment in 50 L fermentation tank.The optimal medium components were determined as following:glucose 140 g/L,NH₄NO₃ 3.0 g/L,dried corn steep liquor powder 0.2 g/L,H₂PO₄ 0.05 g/L, MgSO₄·7H₂O 0.5 g/L,CuSO₄·5H₂O 65 mg/L.The optimal culture conditions were determined as following:initial pH 2.0,60～80 mL of medium in 500 mL Erlenmeyer flask with 10～12%inoculums,and shake flask at 220 rpm at 37℃.In 50 L,fermentor the agitation speed was 300 rpm and the ventilation volume was 0.25 vvm.Under the conditions of optimized medium components and culture conditions, in shake flask,the Asp.terreus TN-474 could accumulate 71.83 g/L itaconic acid,and the conversion ratio of acids to glucose reached 56.69%.In 50 L fermentor,the Itaconic Acid production was 77.15 g/L,and the conversion ratio of acids to glucose reached 60.89%,which is 4.20%more than shake flask.