iES Landau, Institute for Environmental Sciences, University of Koblenz-Landau, 76829, Landau, Germany.
Sci Rep. 2022 Oct 7;12(1):16849. doi: 10.1038/s41598-022-20727-1.
In a 28-days experiment, we investigated the dissipation of aflatoxin B1 (AFB1) (0.5-500 [Formula: see text]) by microbial (MD) and photodegradation (PD) in two contrasting soils (sandy loam and clay). Sterile incubation in darkness served as control (C). AFB1 was degraded in all scenarios according to simple first-order kinetics with 50% dissipation times of 20-32 (PD), 19-48 (MD), and 56-65 days (C), respectively. Dissipation rates were significantly lower ([Formula: see text]) in the clay soil than in the sandy loam soil, likely due to photoquenching and strong binding of AFB1 by clay minerals and humic substances. In the sandy loam, dissipation rate of MD decreased in function of initial AFB1 concentration, probably due to toxic effects on degrading microbes. In contrast, in the clay soil the dissipation rate increased with increasing concentration up to 250 [Formula: see text], followed by a sharp decrease at 500 [Formula: see text], indicating an effect of soil texture on the bioavailability of AFB1 to soil microbes. AFB2a was identified as a transformation product in all scenarios. These results confirm the function of soil for AFB1 degradation, which is modulated by abiotic and biotic processes, soil characteristics and initial AFB1 concentration.
在一项为期 28 天的实验中，我们研究了微生物（MD）和光降解（PD）在两种不同土壤（沙壤土和粘土）中对黄曲霉毒素 B1（AFB1）（0.5-500 [公式：见文本]）的消解。无菌黑暗孵育作为对照（C）。AFB1 在所有情况下均根据简单的一级动力学降解，半衰期分别为 20-32 天（PD）、19-48 天（MD）和 56-65 天（C）。在粘土中，MD 的消解速率明显低于[公式：见文本]在沙壤土中，这可能是由于光猝灭和粘土矿物和腐殖质对 AFB1 的强烈结合。在沙壤土中，MD 的消解速率随初始 AFB1 浓度的降低而降低，可能是由于对降解微生物的毒性作用。相比之下，在粘土中，消解速率随浓度增加而增加，最高可达 250 [公式：见文本]，然后在 500 [公式：见文本]时急剧下降，这表明土壤质地对 AFB1 对土壤微生物的生物利用度的影响。在所有情况下均鉴定出 AFB2a 为转化产物。这些结果证实了土壤对 AFB1 降解的作用，这是由非生物和生物过程、土壤特性和初始 AFB1 浓度调节的。
