农用废弃物固态发酵生产衣康酸工艺研究

Solid State Fermentation Condition for Itaconic Acid Production from Agricultural Waste

以土曲霉AS32811为发酵菌种,农用废弃物麸皮7.5g,玉米芯6.0g为出发培养基,在自然pH值条件下采用单因素试验研究碳源、氮源、无机盐对衣康酸产酸效果的影响。结果显示,该菌可以利用实验所选择的碳源生产衣康酸,葡萄糖为碳源时得率最高;氮源实验结果表明,NH4NO3是最适的产酸氮源。在单因素试验的基础上进行了五因素四水平的正交试验以优化产酸工艺。衣康酸生产的优化条件为:250mL三角瓶中加入玉米芯7.5g、麸皮6.0g、葡萄糖4g、营养液25mL(NH4NO3,4g/L;KH2PO4,0.1g/L;MgSO4,6g/L;C6H12O6,4g;ZnSO4.7H2O,0.015g/L),接种量为1mL(1×107孢子/mL)、温度36℃、湿度为65%条件下自然发酵72h,衣康酸产率可达63.5%。以土曲霉AS32811为发酵菌种,农用废弃物麸皮7.5g,玉米芯6.0g为出发培养基,在自然pH值条件下采用单因素试验研究碳源、氮源、无机盐对衣康酸产酸效果的影响。结果显示,该菌可以利用实验所选择的碳源生产衣康酸,葡萄糖为碳源时得率最高;氮源实验结果表明,NH4NO3是最适的产酸氮源。在单因素试验的基础上进行了五因素四水平的正交试验以优化产酸工艺。衣康酸生产的优化条件为:250mL三角瓶中加入玉米芯7.5g、麸皮6.0g、葡萄糖4g、营养液25mL(NH4NO3,4g/L;KH2PO4,0.1g/L;MgSO4,6g/L;C6H12O6,4g;ZnSO4.7H2O,0.015g/L),接种量为1mL(1×107孢子/mL)、温度36℃、湿度为65%条件下自然发酵72h,衣康酸产率可达63.5%。

Aspergillus terreus AS32811 was used for production of itaconic acid from agricultural wastes like bran 7.5 g and corncob 6.0 g as the starting medium. Effects of single factors like carbon source, nitrogen source and inorganic salt on the production of itconic acid with starting medium at natural pH were studied. Results showed that a variety of carbon sources could be used by the strain for acid production. Glucose was the best one among tested carbon sources. As nitrogen source, NH4NO3 was the best candidate for itaconic acid production. On the basis of single factor result, the orthogonal test with five factors - 4 levels was made for optimizing the itaconic acid production condition. The results showed the order of all the factors affecting acid production was NH4NO3 〉C6H12O6〉ZnSO4〉MgSO4 〉KH2PO4. The optimal composition of the medium was as follow ： in 250 mL flask bran 7.5 g, corncob 6.0 g, glucose 4.0g, 25mL nutrient solution （NH4NO3, 4 g / L; KH2PO4, 0.1 g / L; MgSO4 , 6 g / L; glucose, 4 g; ZnSO4 · 7H2O, 0. 015 g/L）, 1 mL inoculum of 1×10^7 spores, moisture 65%. After incubated at 36℃ for 72 h, the acid production was 63.5 % （w/w dried medium）.