【作者】 张颖；

【导师】 杜连祥；

【作者基本信息】 天津科技大学 ， 发酵工程， 2004， 硕士

【摘要】 本论文对总状共头霉Sr．菌(SyncephaJastrum racemosum)产生抗线虫活性物质的发酵条件进行了优化，并分析了发酵滤液的理化性质，对活性物质分离进行了探讨。 通过培养基组分的单因子试验、方差和显著性水平分析，确定了最佳发酵培养基配方为：去皮马铃薯200g／L煮汁，蔗糖20g／L，pH自然；最适发酵条件为500ml三角瓶装量100ml，接种量2％，170r／min，26℃，培养4d。发酵滤液1／2浓度的杀线虫活性达到85％以上。5L发酵罐放大培养条件为一级种子静置培养24h，按接种量4％接入装有3.5L发酵培养基的5L发酵罐中，起始通气量1：0.5，搅拌转速300～400r／min，发酵54h。发酵滤液1／2浓度的杀线虫活性达到95％以上。 本论文研究了菌体形态与发酵滤液抗线虫活性之间的关系，发现摇瓶条件下形成直径2～4mm的乳白色菌球，发酵滤液抗线活性较高，菌球形态较为稳定。又通过扫描电镜观察不同发酵条件下形成的菌丝球内部、外部形态，发现当菌球过大时，外部菌丝纤细致密，内部形成空腔，菌丝干瘪，养分传输受阻致使发酵滤液活性低下；当菌球过小时，菌丝质地坚密，不易伸展，影响传质，发酵滤液活性也较低；只有形成直径2mm～4mm的大小适中的菌球，外部菌丝大多饱满，内部菌丝松软，有利于外部养分和氧的传递，发酵滤液抗线虫活性较高。通过研究菌体形态与发酵滤液抗线虫活性之间的关系，为发酵结果提供表观依据。 对发酵滤液的理化性质进行了研究，结果表明抗线虫活性物质是一种水溶性物质，不易溶于有机溶剂，具有热稳定性，121℃处理30min，仍保持较高的活性。 对发酵滤液中的活性物质进行分离，发现Sr．菌产生的抗线虫活性物质包括有机酸类物质和非有机酸类活性组分。经过HPLC、GC-MS分析，得知有机酸类含有草酸、柠檬酸，琥珀酸和一个未知组分，还含有长链饱和脂肪酸和不饱和脂肪酸的可能性；通过凝胶柱G25、薄层TLC对非有机酸类活性成分进行分离，结合红外光谱分析初步得出其为含有氨基、糖环的多组分化合物，有待进一步纯化。更多还原

【Abstract】 The fermentation process of the nematicidal bio-active substances from Syncephalastrum racemosum, primary separation and the properties of the bio-active substances were studied.By single factor and statistical analysis, the optimum medium, which is composed of sucrose 20g/L and peeled potato 200g/L with natural pH, and the optimal condition were determined. The 2×106 spores of fungus were incubated in 500ml conical flask with 100ml liquid cultural medium under 170r/min for 4 days at 26 ℃. The nematicidal rate reached above 85% in the one time diluted fermentation solution. During fermentation process on fermenter the nematicidal rate of one time diluted fermentation solution reached above 95% from 44h to 52h.The relationship between the morpha of Sr. and the nematicidal activity of the bio-active substances was studied. It was found that the pellets with diameter from 2mm to 4mm were formed under the optimal conditions. On the basis of observing The morpha of fungus under different condition was observed by the Scan Electronic Microscope (SEM). The result showed that when the pellet was too big, the filamentous were compact on the surface of pellets and hollow was formed inside because of the nutrient prohibition; when pellet was too small, the filamentous were hard and the nematicidal activity of the bio-active substances was low. Only when the pellets with diameter from 2mm to 4mm were formed, the filamentous were plump and the nematicidal activity was high. The gist of fermentation was provided by the study of the relationship between the morpha of Sr. and the nematicidal activity of the bio-active substances.Some properties of the fermentation liquid were studied. The results showed that nematicidal bio-active substances were water-solubility and steady with heat. It kept high bio-activity after being dealed with 30min in 121 ℃.The primary separation of bio-active sunstances was studied, too. It was concluded that nematicidal bio-active substances was composed of organic acids and non-acids. It was found that oxalic acid, citric acid and some acids else were metabolized by Sr. through HPLC, GC-MS. In addition, it was probably saturated and unsaturated fatty acids were metabolized, too. Primary separated by TLC and Sephadex G25, the bio-active substances were composed of compounds with amido and gluco- excepting organic acids. The purification of bio-activesubstances was necessary in the future.更多还原