Biomass generation and heterologous isoprenoid milking from engineered microalgae grown in anaerobic membrane bioreactor effluent

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11 Scopus citations

Abstract

Wastewater (WW) treatment in anaerobic membrane bioreactors (AnMBR) is considered more sustainable than in aerobic reactors. However, outputs from AnMBR are a mixed methane and carbon dioxide gas stream as well as ammonium- (N) and phosphate- (P) containing waters. Using AnMBR outputs as inputs for photoautotrophic algal cultivation can strip the CO2 while removing N and P from effluent which feed algal biomass generation. Recent advances in algal engineering have generated strains that produce high-value side products concomitant with biomass, although only shown in heavily domesticated, lab-adapted strains. Here, it was investigated whether engineered Chlamydomonas reinhardtii could be grown directly in AnMBR effluent with CO2 concentrations found in AnMBR off-gas. The strain was found to proliferate over bacteria in the non-sterile effluent, consume N and P to levels that meet general discharge or reuse limits, and tolerate cultivation in modelled (extreme) outdoor environmental conditions prevalent along the central Red Sea coast. In addition to ∼2.4 g CDW L–1 biomass production in 96 h, a high-value heterologous sesquiterpene co-product could be obtained from ‘milking’ up to 837 µg L–1 culture in 96 h. This is the first demonstration of a combined bio-process that employs a heavily engineered algal strain to enhance the product generation potentials from AnMBR effluent treatment. This study shows it is possible to convert waste into value through use of engineered algae while also improving wastewater treatment economics through co-product generation.

Original languageEnglish (US)
Article number119486
JournalWater research
Volume229
DOIs
StatePublished - Feb 1 2023

Bibliographical note

Funding Information:
We would like to express special thanks to the Coastal and Marine Resources Core Lab (CMR) at KAUST for providing the temperature and PAR data sets used in this study. We are grateful to Paulo C. Aurelio from KAUST Lab Equipment Maintenance (LEM) team for his efforts to install and maintain the Algem Photobioreactors and NxT flow cytometer. The graphical abstract was kindly prepared by Sergio Gutiérrez in part with BioRender and Fig. 1 by Ivan Gromicho, Scientific Illustrator at KAUST. The authors would like to acknowledge KAUST for financial support.

Funding Information:
The research reported in this publication was supported by the KAUST Impact Acceleration Funds program (grant 4224) and KAUST baseline funding awarded to PYH and KL.

Funding Information:
We would like to express special thanks to the Coastal and Marine Resources Core Lab (CMR) at KAUST for providing the temperature and PAR data sets used in this study. We are grateful to Paulo C. Aurelio from KAUST Lab Equipment Maintenance (LEM) team for his efforts to install and maintain the Algem Photobioreactors and NxT flow cytometer. The graphical abstract was kindly prepared by Sergio Gutiérrez in part with BioRender and Fig. 1 by Ivan Gromicho, Scientific Illustrator at KAUST. The authors would like to acknowledge KAUST for financial support.

Publisher Copyright:
© 2022 The Author(s)

Keywords

  • Anaerobic membrane bioreactor (AnMBR)
  • Chlamydomonas reinhardtii
  • CO capture
  • Patchoulol
  • Terpenoids
  • Wastewater treatment

ASJC Scopus subject areas

  • Environmental Engineering
  • Civil and Structural Engineering
  • Ecological Modeling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

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