棘托竹荪抑菌物质的乙醇提取工艺优化与抑菌作用

为研究棘托竹荪Dictyophora echinovolvata乙醇提取物对食品腐败菌和植物病原菌的抑菌作用，以不同体积分数乙醇溶液为提取剂，对棘托竹荪子实体进行浸提，通过单因素和正交试验测定了乙醇体积分数、料液比、浸提时间和浸提温度等4个因素对棘托竹荪提取物抑菌效果的影响，获得的最佳提取工艺为乙醇体积分数90%，料液比50.0 g·L-1，浸提时间2.0 h，浸提温度75℃。用牛津杯法和菌丝生长速率法分别测定了棘托竹荪乙醇提取液对食品腐败菌与植物病原菌的抑菌作用。结果表明:棘托竹荪乙醇提取液对食品腐败细菌和植物病原真菌均具有抑制作用，但对啤酒酵母不表现抑制作用。在供试的4种食品腐败细菌中，抑菌效果从高到低依次是金黄色葡萄球菌Staphylococcus aureus，枯草芽孢杆菌Bacillus subtilis，蜡状芽孢杆菌Bacillus cereus，大肠埃希菌Escherichia coli，抑菌圈直径分别为24.08，23.12，23.02和22.16 mm，可见棘托竹荪乙醇提取液对革兰氏阳性细菌的抑菌效果显著大于革兰氏阴性细菌。在供试的5种植物病原真菌中，抑菌效果从高到低依次为玉米大斑病菌Exserohilum turcicum，油菜菌核病菌Sclerotinia sclerotiorum，番茄灰霉病菌Botrytis cinerea，小麦赤霉病菌Fusarium graminearum，苹果腐烂病菌Valsa mali，抑菌率分别为75.01%，57.67%，49.65%，21.34%和9.26%，且五者间均存在显著性差异（P<0.05），可见棘托竹荪乙醇提取液对真菌的抑菌作用因菌种而异。图4表4参16

Antibiotic activity of Dictyophora echinovolvata and optimization of the ethanol extracted antibiotic substance

To study the antibiotic activity of Dictyophora echinovolvata on food spoilage microorganisms and phytopathogenic fungi and to provide a theoretical basis for developing D. echinovolvata into a natural food preservative and a green biological pesticide, an antibiotic extraction of the D. echinovolvata fruiting body was prepared by boiling an ethanol extract. Single factor and orthogonal experiments were used to determine the optimal extraction parameters. Four factors was optimized included ethanol concentration, ratio of material to solvent, extraction time and extraction temperature. Antibiotic activity was determined by the Oxford cup method and mycelium growth rate method. The size of the inhibitory zone diameter was to evaluate antibacterial ability of food spoilage microorganisms, and the inhibitory rate was used for phytopathogenic fungi, with three replications. Results showed that the optimal extraction parameters were ethanol concentration-90%, ratio of material to solvent-50.0 g·L-1, extraction time-2.0 h, and extraction temperature-75℃. Extract from D. echinovolvata exhibited a strong antibiotic effect on food spoilage bacteria and phytopathogenic fungi, but no inhibitory effect on Saccharomyces cerevisiae. For four selected species of bacteria causing food decay, the successive order for the bacteriostatic effect with inhibitory zone diameter (in mm) was Staphylococcus aureus (24.08), Bacillus subtilis (23.12), Bacillus cereus (23.02), and Escherichia coli (22.16). The antibiotic effect of gram positive bacteria was significantly greater (P<0.05) than the antibiotic effect of gram-negative bacteria. Five selected phytopathogenic fungi were significantly different (P<0.05) for bacteriostatic effect and inhibitory rate (%) with the successive order being Exserohilum turcicum (75.0%), Sclerotinia sclerotiorum (57.7%), Botrytis cinerea (49.7%), Fusarium graminearum (21.3%), and Valsa mali (9.3%). Obviously, there is a great potential for developing D. echinovolvata into natural food preservatives and green biological pesticide.Ch, 4 fig. 4 tab. 16 ref.]