Study On The Preparation Of Chitin And Chitosan By Microorganism

This project adopts the method of producing mycelium by fermentation of mucedine,regulates the composition,proportion and culture conditions of the medium in the fermentation process,and at the same time finds the optimal conditions suitable for industrial removal of impurities such as protein and ash in mycelium,and reduces wastewater discharge.Final determination:The optimal fermentation conditions and medium components for shake flask fermentation:shake flask volume is 100ml/250ml,temperature is 28?,fermentation is 48h,rotation speed is 200rmp/min,and soluble starch and glucose ratio is 15.0g/L:5.0g/L,No.3peptone 10.0 g/L,corn syrup 20.0g/L,ammonium dihydrogen phosphate 1.0g/L,pH 7.0,and the inoculum amount was 15%of the volume of the seed liquid.After optimization of the fermentation conditions,the yield of dried cells was 11.92 g/L,and the yield of chitin was3.96 g/L.5L fermenter fermentation initial medium composition and conditions:starting speed200rpm/min,aeration volume 2.0vvm,increasing speed of 30rpm/min every 4h,aeration increase 0.15vvm,temperature 28?,fermentation time 48h,soluble starch 5.0g/L,glucose5.0g/L,No.3 peptone 5.0g/L,supplemented with soluble starch 10.0g/L and No.3 peptone5.0g/L for 20h with sugar concentration less than 5.0g/L,bacterial cell The biomass was 15.13g/L and the chitin yield was 4.96 g/L.In the 100L fermenter experiment,the biomass of the cells was 16.32 g/L,and the yield of chitin was 5.35 g/L.Batch fermentation and fed-batch fermentation of the fermented fermentation broth showed that the yield of chitin produced by batch fermentation was 2.01g/L and 2.37g/L,and the fermentation broth was fed in batches.The chitin yield was 2.72 g/L and 3.09 g/L.Optimization of extraction conditions,optimal conditions for acid treatment:1mo/l HCl,treatment temperature 10?,treatment time 12h,solid-liquid ratio 1:20,treatment 2 times;alkali treatment optimal conditions:2mol/l NaOH,treatment temperature 20?,treatment time 5h,solid-liquid ratio 1:20,treatment 3 times;protein content 0.64%,ash content 0.98%,the final chitin yield was 41.15%.The optimal experimental conditions in the deacetylation experiment:alkali concentration is 50%,treatment time is 3h,treatment temperature is 120?,solid-liquid ratio is 1:20;ash content is 1.19%,protein content is 0.23%,chitosan The yield was 14.55%and the degree of deacetylation was 90.2%.The measurement showed a viscosity of 5.60 mPa·s and a molecular weight of 7.65×10~4.At the same time,the structure of the purified sample chitosan was characterized by infrared and nuclear magnetic characterization,and its consistency with the control group and chemical shift was determined.