【作者】 胡现龙；

【导师】 李兰生；

【作者基本信息】 中国海洋大学 ， 环境科学， 2008， 硕士

【摘要】 本论文研究了植物激素对固定化黑曲霉发酵法生产葡萄糖酸的影响,主要研究了植物激素对黑曲霉生长的增殖作用、植物激素应用于黑曲霉葡萄糖酸发酵和植物激素应用于固定化黑曲霉菌的葡萄糖酸发酵的作用。首先是通过筛选不同的植物激素对黑曲霉生长的促进作用,采用测定菌液光密度的方法判断黑曲霉的生长情况,并最终得到以赤霉素对黑曲霉的生长促进作用最为明显。然后研究了赤霉素对黑曲霉液体发酵法促进葡萄糖向葡萄糖酸的转化作用,采用3,5—二硝基水杨酸比色法测定还原糖的含量,得出赤霉素可以促进葡萄糖向葡萄糖酸的转化。最后采用包埋法(固定化材料是海藻酸钠)固定化黑曲霉,并应用于发酵实验,在固定化过程中分别添加二氧化硅和蒙脱土改进固定化方法,同样对发酵液进行还原糖的测定以筛选出最佳固定化黑曲霉的改进方法,得到黑曲霉的最佳固定化条件以应用于葡萄糖酸的生产和研究中。本文的实验结果主要有:1.对黑曲霉增殖培养的实验结果表明三十烷醇、赤霉素和α-萘乙酸这3种植物生长激素在低浓度下(0.1mg/L-1.0mg/L)对黑曲霉的生长均有促进作用,其中赤霉素的增殖作用最明显。2.将赤霉素加入到黑曲霉液体发酵培养基中,结果表明不同浓度的赤霉素对黑曲霉增殖都有影响。质量浓度为0.05、0.1、0.5、1.0、1.5mg/L的5个处理组64小时后菌浓度分别比对照组提高了25.12%、35.39%、32.16%、50.44%和31.38%。最佳质量浓度为1.0mg/L,此处理浓度下赤霉素对黑曲霉增殖的促进作用在接种后48h就明显表现出来。3.将赤霉素加入到黑曲霉液体发酵培养基中,对发酵法生产葡萄糖酸的各组发酵液进行还原糖测定,赤霉素对葡萄糖转化为葡萄糖酸有促进作用,得出最佳质量浓度为1.0mg/L。4.以海藻酸钠包埋法对黑曲霉进行固定化,采用加入不同材料的方法对固定化方法进行改进,得到采用质量浓度为3%的海藻酸钠和质量浓度为3%的CaCl2,同时固定化细胞的使用次数为4-5次,该条件下,采用分别加入二氧化硅和蒙脱土粉末的方法,蒙脱土固定化小球对葡萄糖的促进转化能力最强。以上结果表明将植物激素应用于黑曲霉的葡萄糖酸发酵中,能够达到促进黑曲霉发酵菌增殖的目的,既保证黑曲霉的快速生长优势,又可以促进葡萄糖酸的发酵。同时采用将不同材料加入固定化黑曲霉中固定化黑曲霉的方法来促进葡萄糖酸的生成,对实际生产有重要的指导意义。更多还原

【Abstract】 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.更多还原