Application future
Microcystin-LR very stable and in some extent is very resistant to high temperature and pH change, so it is difficult to be clear out by an ordinary drinking water treatment process. After a large-scale outbreak of blue-green algae, microcystin-LR presence can be detected in drinking water in residential home. Because the great damage to liver, microcystin-LR must be removed form the residents drinking water.
There are a variety of microcystin biodegradation reports, in the degradation pathway, microcystinase (MlrA) is the first enzyme to hydrolyze cyclic microcystin LR into a linear intermediate. Because the toxicity of linear microcystin LR decreases about 160 times, MlrA has been regarded as a crucial enzyme for removal of the toxin (Bourne et al., 1996).
Mlr promoter is able to detect whether water containing microcystin LR and start to express the GFP-mlrA fusion protein. GFP can emit green fluorescence, very simple and very sensitive to tell us the water contains toxic microcystin LR. MlrA can directly degrade microcystin LR and eliminate its toxicity, eliminate the toxins in water pollution.
The mlr promoter-GFP-mlrA was be cloned into the E. coli-L. lactis shuttle expression vector pMG36e, so it can be able to express in E. coli and Lactococcus lactis, which Can easily be constructed in the laboratory, at the same time to avoid secondary pollution in the natural environment of E. coli.
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