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Novel microbes on biodegradation of water borne hepatotoxin, mcrocystins
By Admin | July 11, 2009
Microcystin (MCLR) is a hepatotoxin produced by cyanobacterial species including Microcystis, Anabaena, Nostoc and Planktothrix. Recently, it has been recorded that some agricultural, recreational and drinking water bodies of Sri Lanka has contaminated with hepatotoxin, microcystins. Microcystins can tolerate heating up to 100˚C, chlorination and other treatments and are potential to severely compromise human health causes liver cancers. The effects of chronic toxicity from MCLR have led the WHO to establish a guide line of 1.0g l-1 as a maximum concentration in drinking water supplies. It is important to know that the removals of cyanotoxins are not accessible for most of the worlds population due to the unaffordable cost. Therefore, to provide safe drinking water is a global challenge due to the occurrence of toxic cyanobacterial bloom. Thus, the most exciting areas for a successful solution to remove cyanotoxin are harnessing microbes. Recent work resulted in the isolation and characterisation of three novel microcystin degrading bacteria. All isolates were screened using Biolog MT2 plates and those positive isolates were shown to be degraded in batch degradation experiments of MCLR in different concentrations (10 g/ml, 1 g/ml and 0.1g/ml). The novel bacterial isolates were shown to be effectively metabolise MCLR within 24 h. Based on the phylogenetic analysis of the 16S rRNA gene sequence, seven of the isolated bacteria were most similar to Arthrobacter spp. Two other bacteria were most similar to Rhodococcus sp. and another isolate was Brevibacterium sp. The bacterial isolates were not shown to contain homologues of the four genes, mlrA, mlrB, mlrC and mlrD previously associated with the degradation of MCLR by Sphingomonas sp. (ACM-3962) was confirmed using polymerase chain reaction (PCR). Thus, this is the first record on bioremediation of cyanotoxins by the Arthrobacter spp., Brevibacterium sp. and Rhodococcus sp. Future work will seek to use the novel isolates to degrade cyanotoxins in drinking water after completing the work on degradation mechanisms, by products and their fate in environment.
Pathmalal M. Manage1, Linda A. Lawton2, Christine Edwards2
1- Department of Zoology, University of Sri Jayewardenepura, Sri Lanka
2- School of Phramacy and Life Sciences, The Robert Gordon University, Aberdeen, United Kingdom
Topics: Pollution control, symposium2008 | 1 Comment »
March 31st, 2010 at 6:05 pm
I am interesting in cyanotoxins-producers in fresh water.
Would you please send me a copy from the article of biodegradation of microcytin