Isolation of Phosphorus-Hyperaccumulating Microalgae from Revolving Algal Biofilm (RAB) Wastewater Treatment Systems

Eric Schaedig, Michael Cantrell, Christopher Urban, Xuefei Zhao, Drew Greene, Jens Dancer, Michael Gross, Jacob Sebesta, Katherine Chou, Jonathan Grabowy, Martin Gross, Kuldip Kumar, Jianping Yu

Research output: Contribution to journalArticlepeer-review

5 Scopus Citations

Abstract

Excess phosphorus (P) in wastewater effluent poses a serious threat to aquatic ecosystems and can spur harmful algal blooms. Revolving algal biofilm (RAB) systems are an emerging technology to recover P from wastewater before discharge into aquatic ecosystems. In RAB systems, a community of microalgae take up and store wastewater P as polyphosphate as they grow in a partially submerged revolving biofilm, which may then be harvested and dried for use as fertilizer in lieu of mined phosphate rock. In this work, we isolated and characterized a total of 101 microalgae strains from active RAB systems across the US Midwest, including 82 green algae, 9 diatoms, and 10 cyanobacteria. Strains were identified by microscopy and 16S/18S ribosomal DNA sequencing, cryopreserved, and screened for elevated P content (as polyphosphate). Seven isolated strains possessed at least 50% more polyphosphate by cell dry weight than a microalgae consortium from a RAB system, with the top strain accumulating nearly threefold more polyphosphate. These top P-hyperaccumulating strains include the green alga Chlamydomonas pulvinata TCF-48 g and the diatoms Eolimna minima TCF-3d and Craticula molestiformis TCF-8d, possessing 11.4, 12.7, and 14.0% polyphosphate by cell dry weight, respectively. As a preliminary test of strain application for recovering P, Chlamydomonas pulvinata TCF-48 g was reinoculated into a bench-scale RAB system containing Bold basal medium. The strain successfully recolonized the system and recovered twofold more P from the medium than a microalgae consortium from a RAB system treating municipal wastewater. These isolated P-hyperaccumulating microalgae may have broad applications in resource recovery from various waste streams, including improving P removal from wastewater.

Original languageAmerican English
Article number1219318
Number of pages12
JournalFrontiers in Microbiology
Volume14
DOIs
StatePublished - 2023

Bibliographical note

Publisher Copyright:
Copyright © 2023 Schaedig, Cantrell, Urban, Zhao, Greene, Dancer, Gross, Sebesta, Chou, Grabowy, Gross, Kumar and Yu.

NREL Publication Number

  • NREL/JA-2700-83725

Keywords

  • algae
  • bioprospecting
  • microalgae
  • phosphorus
  • polyphosphate
  • revolving algal biofilm
  • wastewater

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