Benimeli C S, Castro G R, Chaile A P, Amoroso M J
PROIMI-CONICET, Av. Belgrano y Caseros, 4000 Tucumán, Argentina.
J Basic Microbiol. 2006;46(5):348-57. doi: 10.1002/jobm.200510131.
Gamma-hexachlorocyclohexane (gamma-HCH or lindane), one of the most commonly used pesticides, has been mainly used in agriculture; this pesticide is known to be highly toxic and persistent, causing serious water and soil contamination. The objective of the present work is to study the effect of low glucose concentration and the addition of lindane at different growing time on the pesticide detoxification ability of Streptomyces M7. After 96 h of incubation in synthetic medium containing glucose 0.6 g l(-1) with the addition of lindane 100 microg l(-1) at 20 h of incubation, a typical diauxic curve was obtained: glucose was the preferred substrate until 24 h, at 48 h, when the carbohydrate was depleted, the microorganism consumed the pesticide like carbon source. On the other hand, lindane removal induction was observed, which was greater when the pesticide was added to the medium at 20 h than 6 h of incubation. Between 72 and 96 h, a maximum of approximately 86% of the Cl(-) was released when lindane was added to the medium at 20 h, whereas approximately 70% and 67% Cl(-) was released in the medium when the pesticide was added at 0 and 6 h of incubation respectively. This is the first report of chloride release from inoculated medium supplemented with lindane, suggesting that the pesticide was degraded by Streptomyces sp. under aerobic conditions.
γ-六氯环己烷（γ-HCH或林丹）是最常用的农药之一，主要用于农业；这种农药毒性高且具有持久性，会造成严重的水和土壤污染。本研究的目的是探讨低葡萄糖浓度以及在不同生长时间添加林丹对链霉菌M7农药解毒能力的影响。在含有0.6 g l⁻¹葡萄糖的合成培养基中培养96小时，并在培养20小时时添加100 μg l⁻¹林丹，得到了典型的双相生长曲线：直到24小时，葡萄糖是首选底物，在48小时时，碳水化合物耗尽，微生物将农药作为碳源消耗。另一方面，观察到林丹去除诱导现象，当在培养20小时而非6小时时向培养基中添加农药，诱导作用更强。在72至96小时之间，当在培养20小时时向培养基中添加林丹时，最多约86%的Cl⁻被释放，而当在培养0小时和6小时时添加农药时，培养基中分别释放了约70%和67%的Cl⁻。这是关于接种了林丹的培养基中氯离子释放的首次报道，表明该农药在有氧条件下被链霉菌属降解。
