A Novel and Native Microcystin-Degrading Bacterium of Sphingopyxis sp. Isolated from Lake Taihu.

Juan Zhang,Yuepu Pu,Lihong Yin,Qingqing Lu,Qin Ding

doi:10.3390/ijerph14101187

Abstract

A native, highly efficient microcystin-LR (MC-LR)-degrading bacterium named a7 was isolated from Lake Taihu and identified as Sphingopyxis sp. by 16S rDNA sequence analysis. The strain a7 could totally degrade MC-LR at a rate of 3.33 mg/(L·h), as detected by high-performance liquid chromatography (HPLC). The mlrA, mlrC, and mlrD genes were detected in the strain a7 by sequence analysis. Tetrapeptide and Adda—which are the middle metabolites of MC-LR—were analyzed via liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) during degradation. These metabolites were degraded completely, which suggested that the native Sphingopyxis sp. a7 was highly efficient in MC-LR degradation under bench conditions. Thus, strain a7 exhibited a significant potential application for bioremediation in water bodies contaminated by MC-LR produced by harmful cyanobacterial blooms.

Highlights

Microcystins(MCs)(MCs) are are cyclic heptapeptides heptapeptides with of Microcystins with seven sevenamino aminoacids, acids,and andare areconsidered consideredone one the most hazardous groups of toxins produced by harmful cyanobacterial blooms (HCBs) [1,2].These of the most hazardous groups of toxins produced by harmful cyanobacterial blooms (HCBs) [1,2].toxinstoxins are cyclic heptapeptide hepatotoxins and tumor-promoting substances [3,4]
Anative and highly efficient MC-LR-degrading bacterium was isolated from Lake Taihu and identified as Sphingopyxis sp., according to the 16S rDNA sequence
Adda, which were the metabolites of MC-LR catalyzed by microcystinases

Summary

Introduction

Microcystins(MCs)(MCs) are are cyclic heptapeptides heptapeptides with of Microcystins with seven sevenamino aminoacids, acids,and andare areconsidered consideredone one the most hazardous groups of toxins produced by harmful cyanobacterial blooms (HCBs) [1,2].These of the most hazardous groups of toxins produced by harmful cyanobacterial blooms (HCBs) [1,2].toxinstoxins are cyclic heptapeptide hepatotoxins and tumor-promoting substances [3,4]. (MCs) are are cyclic heptapeptides heptapeptides with of Microcystins with seven sevenamino aminoacids, acids,and andare areconsidered consideredone one the most hazardous groups of toxins produced by harmful cyanobacterial blooms (HCBs) [1,2]. These of the most hazardous groups of toxins produced by harmful cyanobacterial blooms (HCBs) [1,2]. Toxinstoxins are cyclic heptapeptide hepatotoxins and tumor-promoting substances [3,4]. These are cyclic heptapeptide hepatotoxins and tumor-promoting substances [3,4].

Objectives

Results

Discussion

Conclusion