Microcystin-LR Removal from Water via Enzymatic Linearization and Ultrafiltration

Abelline Fionah, Cannon Hackett, Hazim Aljewari, Laura Brady, Faisal Alqhtani, Isabel C. Escobar, Audie K. Thompson

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Microcystin-LR (MC-LR) is a toxin produced by cyanobacteria that can bloom in freshwater supplies. This study describes a new strategy for remediation of MC-LR that combines linearization of the toxin using microcystin and e A and MlrA enzyme with rejection of linearized byproducts using membrane filtration. The MlrA enzyme was expressed in Escherichia coli (E. coli) and purified via a His-tag with 95% purity. Additionally, composite membranes made of 95% polysulfone and 5% sulfonated polyether ether ketone (SPEEK) were fabricated and used to filter a solution containing cyclic and linearized MC-LR. Tests were also performed to measure the adsorption and desorption of MC-LR on polysulfone/SPEEK membranes. Liquid chromatography-mass spectrometry (LC-MS) was used to characterize the progress of linearization and removal of MC-LR. Results indicate that the MlrA was successful at linearizing MC-LR. Membrane filtration tests showed rejection of 97% of cyclic MC-LR and virtually all linearized MC-LR, with adsorption to the membranes being the main rejection mechanism. Adsorption/desorption tests indicated that methanol could be used to strip residual MC-LR from membranes to regenerate them. This study demonstrates a novel strategy of remediation of microcystin-tainted water, combining linearization of MC-LR to a low-toxicity byproduct along with removal by membrane filtration.

Original languageEnglish
Article number231
JournalToxins
Volume14
Issue number4
DOIs
StatePublished - Apr 2022

Bibliographical note

Publisher Copyright:
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.

Keywords

  • enzyme
  • harmful algal blooms
  • linearization
  • microcystin
  • ultrafiltration

ASJC Scopus subject areas

  • Toxicology
  • Health, Toxicology and Mutagenesis

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