Accelerated sunlight-driven conversion of industrial flue gas into biofuels by microfluidic high-throughput screening towards improving photosynthesis in microalgae under fluctuating light

Young Joon Sung, Jeong Seop Lee, Sang Jun Sim

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Sunlight-driven microalgal conversion of CO2 is a promising carbon neutral strategy for the sustainable production of various value-added products. However, its real-world application is challenging due to the irregularity of sunlight which reduces photosynthetic efficiency. Here, we report that microdroplet-based screening of photosynthesis-augmented microalgae mutant under fluctuating light accelerates mass production of CO2-derived algal biofuel in natural sunlight. Random insertional Chlamydomonas reinhardtii mutants were cultivated in single-layered microdroplet photobioreactors to be effectively applied to light conditions mimicking natural sunlight without self-shading. High-density microdroplets containing fast-growing mutants were efficiently selected at the single-droplet level by a centrifugation-assisted droplet sorting platform for high-throughput screening. Consequently, we isolated a mutant exhibiting cell growth 1.85-fold that of the wild-type even under continuous and rapid alteration in light intensity, which can serve as a cell stressor. After whole-genome resequencing, we found disruption in the SNF2 gene encoding ATP-dependent chromatin remodeling complexes, which reveal its importance for the regulation of chlorophyll biosynthesis and accumulation of reactive oxygen species under fluctuating light. After a 1.6 ton-scale field culture utilizing natural sunlight and industrial CO2, the mutant showed increased biomass productivity, CO2 fixation rate, and calorific value, a crucial parameter of fuel performance, by 34.38%, 45.07%, and 16.82%, respectively. Our results indicate that improving photosynthesis of microalgae in fluctuating light environments elucidates the mechanisms responsible for enhancing the sunlight utilization, allowing industrial-scale biological CO2 conversion.

Original languageEnglish
Article number136487
JournalChemical Engineering Journal
Volume443
DOIs
Publication statusPublished - 2022 Sep 1

Keywords

  • Biofuel
  • Biological conversion of CO
  • Flue gas
  • Gel microdroplet-based screening
  • Microalgae
  • SNF2 gene

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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