Planta Piloto de Procesos Industriales Microbiológicos (PROIMI-CONICET), Avenida Belgrano y Pasaje Caseros, Tucumán 4000, Argentina; Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán (UNT), Miguel Lillo 205, Tucumán 4000, Argentina.
Instituto de Investigaciones Agrobiológicas de Galicia (IIAG), Consejo Superior de Investigaciones Científicas (CSIC), Avda. de Vigo s/n, Santiago de Compostela 15705, Spain.
J Hazard Mater. 2022 Jul 5;433:128764. doi: 10.1016/j.jhazmat.2022.128764. Epub 2022 Mar 23.
Lindane and other 1,2,3,4,5,6-hexachlorocyclohexane (HCH) isomers are persistent organic pollutants highly hydrophobic, which hampers their availability and biodegradation. This work aimed at (i) investigating genes encoding enzymes involved in HCH degradation in the bacterium Sphingobium sp. D4, (ii) selecting strains, from a collection of environmental isolates, able to mobilize HCHs from contaminated soil, and (iii) analysing the biodegradation of HCHs by strain D4 in co-culture with HCH-mobilizing strains or when cultivated with root exudates. Fragments of the same size and similar sequence to linA and linB genes were successfully amplified. Two isolates, Streptomyces sp. M7 and Rhodococcus erythropolis ET54b able to produce emulsifiers and to mobilize HCH isomers from soil were selected. Biodegradation of HCH isomers by strain D4 was enhanced when co-inoculated with HCH mobilizing strains or when cultivated with root exudates. The degrader strain D4 was able to decompose very efficiently HCHs isomers, reducing their concentration in soil slurries by more than 95% (from an average initial amount of 50 ± 8 mg HCH kg soil) in 9 days. The combination of HCH-degrading and HCH-mobilizing strains can be considered a promising inoculum for future soil bioremediation studies using bioaugmentation techniques or in combination with plants in rhizodegradation assays.
林丹和其他 1,2,3,4,5,6-六氯环己烷（HCH）异构体是高度疏水性的持久性有机污染物，这阻碍了它们的可用性和生物降解。本工作旨在：（i）研究编码参与细菌 sp. D4 中 HCH 降解的酶的基因，（ii）从环境分离株中选择能够从污染土壤中动员 HCH 的菌株，以及（iii）分析 D4 菌株与动员 HCH 的菌株共培养或与根分泌物一起培养时 HCH 的生物降解。成功扩增了 linA 和 linB 基因大小相同且序列相似的片段。选择了能够产生乳化剂和从土壤中动员 HCH 异构体的 Streptomyces sp. M7 和 Rhodococcus erythropolis ET54b 两种分离株。当与动员 HCH 的菌株共接种或与根分泌物一起培养时，D4 菌株对 HCH 异构体的生物降解得到增强。降解菌 D4 能够非常有效地分解 HCH 异构体，在 9 天内将土壤悬浮液中的浓度降低了 95%以上（从平均初始浓度 50±8mg HCH kg 土壤）。HCH 降解菌和动员菌的组合可以被认为是未来使用生物强化技术或与植物在根降解试验中结合进行土壤生物修复研究的有前途的接种物。
