?耐鉛菌株的分離鑒定及其吸附特性研究

吳海維 周娜娜 姜宇 朱曙光 鮑立寧

摘 要：以某工廠處理水剩余污泥為菌種來源，經過分離、培養，篩選出一株最大耐Pb2+濃度為800 mg/L的耐鉛菌株，命名為J2，應用16S rDNA基因測序，結合形態觀察和生理生化特性試驗確定其類別，并對其Pb2+去除特性進行初步研究。結果表明：J2菌株屬于寡養單胞菌屬（Stenotrophomonas）細菌;其去除鉛的最佳pH值為9、最適接種量為5%、最適溫度為30℃、最佳發酵時間為96 h;根據J2菌株吸附鉛前后掃描電鏡結果，結合菌株生長曲線分析，認為J2菌株對鉛的去除機理包括前期表面吸附和后期胞內累積或轉化2種形式。該菌株可為重金屬污染土壤微生物修復提供菌種資源。

關鍵詞：土壤重金屬污染;耐鉛菌株;篩選;鑒定;吸附特性;吸附機理

中圖分類號：Q815， X172 文獻標識碼：A文章編號：1006-060X（2020）07-0005-04

Abstract： A lead-resistant strain survived in a maximum Pb2+ concentration of 800 mg/L was selected from the excess sludge of a plant and named J2 after isolation and culture. The obtained strain was subjected to 16S rDNA sequencing in succession to morphological observation， and physiological and biochemical charteristics tests. It was identified as Stenotrophomonas sp. based on 16S rDNA sequence similarity analysis. In addition， its Pb2+ removal characteristics was identified. The optimal lead adsorption conditions of this strain are pH 9，? inoculum concentration 5%， 30℃ and incubation 96 h. The repair mechanism of J2 strain is mainly cell surface adsorption at early stage and intracellular enrichment/transformation at late stage based on the analysis of the growth curve and scanning electron microscopy. Our studies confirm that the screened strain J2 has a good adsorption effect on lead and can provide bacteria resources for microbial remediation of heavy metal contaminated soil.

Key words： soil heavy metal pollution; lead-resistant strains; selecting; identification; adsorption characteristics; adsorption mechanism

在自然中大多數重金屬都以低濃度存在于土壤、水、巖石和生物群中，為生命系統提供必需的營養，一旦某種或某幾種重金屬的含量過高便會引起毒性。鉛是一種自然普遍存在的金屬，但是因為人類活動極大地提高了其在環境中的含量，例如鉛礦開采、使用鉛作為原料的工業過程、煤炭和石油的燃燒等活動[1]。由于鉛在土壤中的停留時間長，易通過水圈、大氣層影響生物圈，進而通過食物鏈影響人類的健康，因此，土壤中的鉛污染應引起人們的重視[2]。

為了保護環境，避免人類健康受損害，土壤重金屬污染的修復是國內外學者研究的熱點。微生物修復因為費用低、效果好、不會或很少造成二次污染，逐漸取代了傳統的物理修復和化學修復[3]。……