The Effects Of Plant Hormone On The Growth Of Aspergillus Niger And Immobilization Of Aspergillus Niger

The effects of plant hormones on production of gluconic acid by immobilized Aspergillus niger are explored in this dissertation.This paper mainly studies the proliferation of Aspergillus niger using plant hormones,influence of plant hormones to production of gluconic acid by Aspergillus niger and immobilized Aspergillus niger.Firstly the infuences of different plant growth hormones on the growth of Aspergillus niger are explored.Bacilli optical density for judging the growth of Aspergillus niger is adopted. The effect of GA to the growth of Aspergillus niger is the most obvious. Then the plant hormones on conversion of glucose to gluconic acid by Aspergillus niger liquid fermentation is examined. GA can promote glucose to gluconic acid conversion by determination of reducing sugar content using the method of DNS.Finally,the fermentation of Aspergillus niger immobilized by embedded sodium alginate is studied. In the process of the immobility, silicon dioxide and montmorillonite are introduced.At the same time, reducing sugar content is determined to choose the best plan of immobility.So,the immobilized Aspergillus niger can be applied for the the production and research of Gluconic acid actually. The results of the experiments included:1. The three plant growth hormones (triacontanol,gibberellin andα-naphthylacetic acid)could enhance the growth of Aspergillus niger in low concentration(0.1mg/L-1.0 mg/L).In this aspect, the best is gibberellin.2. GA is added to liquid fermentation medium and it indicates that different concentrations of GA is good for proliferation of Aspergillus niger. Five treatment groups with concentration of 0.05,0.1,0.5,1.0 and 1.5mg/L are respectively increased 25.12%,35.39 %,32.16 %,50.44 % and 31.38 % . The optimum concentration of which is 1.0mg/L and this can be seen after 48 hours.3. GA is added to liquid fermentation medium and reducing sugar content is determined. The results showed that the conversion of glucose to gluconic acid can be promoted by adding to GA.The best concentration of GA is 1.0mg/L.4. Aspergillus niger mobilized by embedded sodium alginate with different materials is studied.The best immobilization consists of 3% of sodium alginate and 3% of CaCl2,and the number of using fixed cells is four to five.Under these conditions,the promotion of GA including silicon dioxide and montmorillonite to the conversion of glucose are explored.Aspergillus niger mobilized by montmorillonite is more effective.The research results demonstrate that the plant hormone used in gluconic acid fermentation by Aspergillus niger is effective. Plant hormone can promote the proliferation of Aspergillus niger and ensure the rapid growth of it. Smultaneity, different materials are joined in the mobilized Aspergillus niger to accelerate the the conversion of glucose to gluconic acid.And it is helpful to the actual production of gluconic acid.