Whole-cell and Pure Enzyme-catalyzed Degradation of Microcystins: A Comparative Study of the Efficacy of Heterologously Expressed mlrA Gene

Abstract

The increasing occurrence of cyanobacterial blooms, driven by factors such as water eutrophication and climate warming, has raised concerns due to associated environmental pollution and health risks. Among the toxins produced by these blooms, microcystins, particularly Microcystin MC-LR, pose significant threats to ecosystems and human health. This study investigates the efficiency of degrading microcystins, particularly Microcystin MC-LR, using two catalytic methods: whole-cell and pure enzyme catalysis, both relying on the mlrA gene. The research successfully engineered an Escherichia coli strain with the capability to degrade MC-LR, achieving remarkable results with the whole-cell catalysis approach. Within a 24-hour period, the concentration of MC-LR dropped from 5 μg/mL to 0.681 μg/mL, demonstrating an efficiency of 84%. In contrast, enzymatic degradation yielded less satisfactory outcomes, degrading only 100 ng/mL within the same timeframe. The whole-cell catalysis approach exhibits clear advantages, including cost-effectiveness, making it a promising option for industrial applications. This technology holds potential for safeguarding water resources and public health by addressing algal toxin contamination.