Researching On The Production Of Sodium Gluconate By Immobilized GOD

This thesis is based on production of sodium gluconate with enzyme.The main research contents include the determination of GOD's extraction conditions, preparation of immobilization of GOD, properties of immobilized enzyme, process conditions of sodium gluconate production by immobilized enzyme.In this paper, waste mycelium of sodium gluconate's production is used in the extraction of GOD. As GOD is intracellular enzyme, first mycelium need to be broken, then glucose oxidase can be released from intracellular, at the same time I should take steps to ensure minimal loss of enzyme activity. After the initial enzyme solution is obtained, it is futher to be purificated and be made into enzymes. Finally the method of waste mycelia broken can be determined, the optimal conditions are: ultrasonic time is 50min, ultrasound temperatures is 60℃, the ultrasonic power is 200W. After waste mycelia is broken, 65% ethanol is used to precipite GOD, and then 16% PEG is used to precipite GOD for the second time.The effects of three carriers for enzyme immobilization were firstly researched, by comparing ease of production of the three immobilized enzyme and activity recovery, at last hydroxyapatite is selected as a carrier. The optimum conditions for immobilization is: the amount of enzyme was 0.07g/mL, temperature 30℃, pH6.5, fixed time 15h.GOD is immobilized with a new nano-materials Hydroxyapatite, then study the enzymatic properties of immobilized enzyme. The effects of temperature, pH, metal ions, storage time on the free enzyme and immobilized enzyme activity are researched . The optimum temperature and pH of immobilized enzyme is 40℃and 6.5, increased by 4℃and 0.9 compared with free enzyme. The average enzyme activity recovery of the immobilized enzyme was 61.32%. In addition, storage stability of the immobilized enzyme is increased. It can be reused for seven times, the remaining enzyme activity was still 62.1%。In this paper, the enzymatic production of sodium gluconate on substrate concentration, temperature, pH, aeration rate and reaction time was optimized. The results showed that: substrate concentration have little effect conversion on the amount of sugar and acid substances;optimum temperature is 40℃, optimum pH is 6.5, ventilation is 10L/min, reaction time is 80h. Orthogonal Preparation of sodium gluconate process optimization, optimal results are: substrate concentration is 400g/L, temperature is 40℃, pH is 6.5, ventilation is 10L/min, reaction time is 80h.