降解多環芳烴和異丙威的耐鎘菌種篩選及其特性研究

摘 要：為獲得既耐受重金屬鎘又能高效降解多環芳烴（菲、芘）、異丙威的菌種，利用選擇培養基從染土壤中分離高效降解微生物，并進行菌種分類和降解特性分析。共篩選獲得2個耐鎘并降解多環芳烴、異丙威的菌種，其中WLX8D對芘降解效率最高；S-200培養15 d內對菲和異丙威的最高降解效率分別為53.6%和 66.7%，結合形態學特征和16S rDNA序列分析，初步鑒定結果，WLX8D為意大利農霉菌（Agromyces italicus），S-200為硫酸鹽還原菌（Salfate reducing bacteria）。WLX8D、S-200對芘、菲的作用濃度和耐鎘濃度范圍廣，WLX8D可降解25～100 mg/L濃度范圍的芘，S-200可以高效降解菲和異丙威（降解率50%～60%），2菌株在鎘濃度25～200 mg/L的培養基中生長良好。因此，WLX8D、S-200在修復鎘與多環芳烴復合污染土壤方面具有潛在的應用價值。

關鍵詞：耐鎘；多環芳烴；異丙威；生物降解；意大利農霉菌；硫酸鹽還原菌

中圖分類號：Q935; X53 文獻標識碼：A 文章編號：1006-060X（2023）07-0011-19

Abstract：To screen out Cd-resistant microorganisms that can also efficiently degrade polycyclic aromatic hydrocarbons （PAHs： phenanthrene and pyrene） or isoprocarb， selective media were used with PAHs or isoprocarb as the sole carbon source. The phylogenetic position of the obtained strains and their degradation characteristics of PAHs and isoprocarb were analyzed. Finally， two Cd-resistant strains which were capable of degrading PAHs or isoprocarb were isolated from contaminated soil. Among them， strain WLX8D was of the highest degradation efficiency for pyrene; as for strain S-200， within 15 days of culture， its maximum degradation efficiency for phenanthrene and isoprocarb was 53.6% and 66.7%， respectively. Based on morphologic characteristics and a 16S rDNA sequence analysis， strain WLX8D was identified as Agromyces italicus， and strain S-200 was a salfate reducing bacterium. WLX8D and S-200 could efficiently degrade diverse concentrations of PAHs （phenanthrene， pyrene） and isoprocarb over a wide range of Cd concentrations （25-200 mg/L）. WLX8D was efficient for 25-100 mg/L of pyrene. S-200 reached a 50% degradation rate for phenanthrene and 60% for isoprocarb. These two strains grew well on the culture medium containing 25-200 mg/L of Cd. These results indicate that WLX8D and S-200 are efficient strains for PAHs and isoprocarb biodegradation and have potential in the bioremediation of Cd and PAHs contaminated soil.

Key words：cadmium resistance; polycyclic aromatic hydrocarbons （PAHs）; isoprocarb; biodegradation; Agromyces italicus; salfate reducing bacteria

由于農田施用的農藥通過地表徑流、污水排放擴散，以及石油、燃料油、煤不完全燃燒產生的廢氣隨大氣顆粒的沉降擴散，導致過量有機農藥和多環芳烴（Polycyclic aromatic hydrocarbons，PAHs）擴散到環境中形成有機污染。異丙威（Isoprocarb） 是一種具有觸殺、胃毒和熏蒸作用，對刺吸式害蟲稻飛虱和葉蟬有很好的防效的氨基甲酸酯類的殺蟲劑[1]。人們為了保障水稻產量需要大量噴施異丙威殺蟲。大量長期使用異丙威導致環境中的農藥殘留日益增加，對人們的身體健康造成嚴重威脅，可能導致人體出現癌癥、畸形和內分泌紊亂等嚴重疾病[2]。

PAHs是一類具有高毒性、熱穩定性、生物富集性、疏水性、不易降解等特性的持久性有機污染物[3]，可通過食物鏈傳遞而在生物體內累積，危害人類健康和生態環境[4]，早在1976年16種PAHs就被美國環保局列為優先控制污染物名單[5]。……