Simultaneous Microcystis Algicidal and Microcystin Degrading Capability by a Single Acinetobacter Bacterial Strain

Area of Science:

• Environmental Microbiology
• Aquatic Toxicology
• Bioremediation

Background:

• Harmful algal blooms (HABs) produce toxins like microcystins (MCs), posing ecological and health risks.
• Current removal methods can inadvertently release these toxins through cell lysis.
• A need exists for efficient methods to both remove algae and degrade associated toxins.

Purpose of the Study:

• To isolate and characterize a bacterial strain capable of both lysing toxic algae and degrading microcystins.
• To investigate the mechanisms and efficiency of a novel bacterial strain, Acinetobacter sp. CMDB-2, in managing Microcystis aeruginosa and its toxins.

Main Methods:

• Isolation and identification of Acinetobacter sp. CMDB-2 with algal lysis and MC degradation capabilities.
• Co-culturing Microcystis aeruginosa with Acinetobacter sp. CMDB-2 under varying bacterial densities.
• Monitoring algal cell integrity, photosynthetic activity, and intra-/extracellular microcystin-LR (MC-LR) concentrations.

Main Results:

• Acinetobacter sp. CMDB-2 rapidly decomposed Microcystis aeruginosa cells and impaired photosynthesis within 24 hours.
• Microcystin-LR (MC-LR) levels were reduced by approximately 94% within 14 hours, largely independent of bacterial density.
• Bacterial cells were responsible for ~91% of MC-LR reduction, while bacterial metabolites caused ~92% of algal cell lysis.

Conclusions:

• Acinetobacter sp. CMDB-2 demonstrates a unique dual capability to lyse toxic algae and degrade microcystins.
• This single bacterial strain offers a sustainable solution for managing harmful algal blooms and their associated toxins.
• This study presents the first report of a single bacterial strain achieving both algal removal and toxin degradation.