Pathway for Biodegrading Nodularin (NOD) by Sphingopyxis sp. USTB-05

Area of Science:

• Environmental Microbiology
• Biotechnology
• Toxicology

Background:

• Nodularin (NOD) is a potent cyanotoxin produced by Nodularia spumigena during harmful algal blooms.
• NOD poses significant risks to human and animal health through contaminated water bodies.

Purpose of the Study:

• To investigate the biodegradation of nodularin (NOD) by the bacterial strain Sphingopyxis sp. USTB-05.
• To elucidate the enzymatic pathways involved in NOD detoxification.

Main Methods:

• Whole-cell biodegradation assays using Sphingopyxis sp. USTB-05.
• Enzymatic assays with crude enzymes (CEs) from USTB-05.
• High-Performance Liquid Chromatography (HPLC) and Liquid Chromatography-Mass Spectrometry (RRLC-MS) for product identification.

Main Results:

• Sphingopyxis sp. USTB-05 completely eliminated 11.6 mg/L NOD within 72 hours.
• Crude enzymes (CEs) degraded NOD within 36 hours.
• Two intermediate products were identified, indicating a two-enzyme biodegradation pathway: hydrolysis of the Arg-Adda bond and subsequent cleavage of the Adda-Glu bond, yielding Adda.

Conclusions:

• Sphingopyxis sp. USTB-05 possesses effective nodularin (NOD) biodegradation capabilities.
• The study identified a two-step enzymatic mechanism for NOD detoxification.
• This research provides a basis for applying USTB-05 in environmental remediation strategies for NOD-contaminated waters.