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将有致病力的甘薯青枯菌在液体肉汁胨培养基中２８～３０℃培养４８～７２ｈ，在无菌条件下经２０００ｒ／ｍｉｎ离心；取上清液再经过０．４５μｍ的细菌过滤膜过滤，获得甘薯青枯菌粗毒素（代谢产物）。粗毒素对热效应较为敏感，在５０℃下水浴１ｈ，生物活性不变；７０℃下水浴１ｈ，生物活性降低２８．７％；１００℃下水浴１ｈ，生物活性几乎完全丧失。粗毒素对紫外线不敏感，在２５Ｗ紫外光下照射３０ｍｉｎ、６０ｍｉｎ、１２０ｍｉｎ均不影响生物活性。粗毒素对蛋白酶和溶菌酶敏感，加入木瓜蛋白酶４～１６ｕ／ｍｌ或加入胰蛋白酶１０～４０ｕ／ｍｌ时生物活性均受破坏，丧失毒力；加入溶菌酶１５０００～６００００ｕ／ｍｌ时生物活性降低了９１．６％～９２．０％，几乎丧失了毒力。
The virulent R. solanacearum is cultured in liquid peptone medium at 28-30 DEG C for 48-72h and centrifuged at 2000r / min under aseptic conditions; the supernatant is passed through a 0.45 mu m bacterial filtration membrane Filtration to obtain R. solanacearum crude toxin (metabolite). Crude toxin was more sensitive to the heat effect, and had the same biological activity at 50 ℃ for 1h. The bioactivity was reduced by 28.7% at 70 ℃ for 1h, and almost completely lost in the water bath at 100 ℃ for 1h. Crude toxin is insensitive to ultraviolet light, irradiating under 25W ultraviolet light for 30min, 60min, 120min does not affect the biological activity. The crude toxin was sensitive to protease and lysozyme. When papain was added at 4 ~ 16u / ml or trypsin was added at 10 ~ 40u / ml, the biological activity was destroyed and the toxicity was lost. The biological activity of lysozyme at 15000 ~ 60000u / ml was decreased 91.6% ~ 92.0%, almost lost the virulence.