Qi Zhang, Wei Zhang
Xinjiang Key Laboratory of Special Species Conservation and Regulatory Biology, Xinjiang Normal University, Xinyi Road, Urumqi, 830054, China.
Environ Sci Pollut Res Int. 2017 Mar;24(7):6554-6562. doi: 10.1007/s11356-017-8370-5. Epub 2017 Jan 10.
In the Xinjiang region of Eurasia, sustained long-term and continuous cropping of cotton over a wide expanse of land is practiced, which requires application of high levels of pyrethroid and other classes of pesticides-resulting in high levels of pesticide residues in the soil. In this study, soil samples were collected from areas of long-term continuous cotton crops with the aim of obtaining microbial resources applicable for remediation of pyrethroid pesticide contamination suitable for the soil type and climate of that area. Soil samples were first used to culture microbial flora capable of degrading beta-cypermethrin using an enrichment culture method. Structural changes and ultimate microbial floral composition during enrichment were analyzed by high-throughput sequencing. Four strains capable of degrading beta-cypermethrin were isolated and preliminarily classified. Finally, comparative rates and speeds of degradation of beta-cypermethrin between relevant microbial flora and single strains were determined. After continuous subculture for 3 weeks, soil sample microbial flora formed a new type of microbial flora by rapid succession, which showed stable growth by utilizing beta-cypermethrin as the sole carbon source (GXzq). This microbial flora mainly consisted of Pseudomonas, Hyphomicrobium, Dokdonella, and Methyloversatilis. Analysis of the microbial flora also permitted separation of four additional strains; i.e., GXZQ4, GXZQ6, GXZQ7, and GXZQ13 that, respectively, belonged to Streptomyces, Enterobacter, Streptomyces, and Pseudomonas. Under culture conditions of 37 °C and 180 rpm, the degradation rate of beta-cypermethrin by GXzq was as high as 89.84% within 96 h, which exceeded that achieved by the single strains GXZQ4, GXZQ6, GXZQ7, and GXZQ13 and their derived microbial flora GXh.
在欧亚大陆的新疆地区，人们在大片土地上长期持续种植棉花，这需要施用大量拟除虫菊酯类及其他种类的农药，导致土壤中农药残留量很高。在本研究中，从长期连续种植棉花的地区采集土壤样本，目的是获取适用于该地区土壤类型和气候的、可用于修复拟除虫菊酯类农药污染的微生物资源。首先使用富集培养法，利用土壤样本培养能够降解高效氯氰菊酯的微生物菌群。通过高通量测序分析富集过程中微生物菌群的结构变化和最终的微生物组成。分离出四株能够降解高效氯氰菊酯的菌株并进行初步分类。最后，测定相关微生物菌群和单一菌株对高效氯氰菊酯的降解率和降解速度。经过连续3周的传代培养后，土壤样本微生物菌群通过快速演替形成了一种新型微生物菌群，该菌群以高效氯氰菊酯作为唯一碳源时生长稳定（GXzq）。这种微生物菌群主要由假单胞菌属、生丝微菌属、陶厄氏菌属和甲基嗜盐碱菌属组成。对该微生物菌群的分析还分离出另外四株菌株，即GXZQ４、GXZQ６、GXZQ７和GXZQ13，它们分别属于链霉菌属、肠杆菌属、链霉菌属和假单胞菌属。在37℃和180 rpm的培养条件下，GXzq在96 h内对高效氯氰菊酯的降解率高达89.84%，超过了单一菌株GXZQ４、GXZQ６、GXZQ７和GXZQ13及其衍生的微生物菌群GXh。
