Regulate oxygen concentration using a co-culture of activated sludge bacteria and Chlorella vulgaris to maximize biophotolytic hydrogen production

Muhammad Asad Javed, Abdul Mannan Zafar, Ashraf Aly Hassan

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

The biophotolytic hydrogen (H2) production is contingent on proper oxygen (O2) concentration regulation. Co-culturing bacteria along with microalgae leads to the uptake of excess O2 produced by algal cells. This uptake of O2 by the bacteria triggers the hydrogenase enzyme activity present in microalgae which is responsible for H2 production. In this study, indigenous bacteria present in activated sludge were co-cultured with Chlorella vulgaris at different ratios. The 1:1.5 v/v (algae to bacteria) co-culture ratio produced the most significant H2 gas volume (1246 mL L−1) with a minimum O2 content (57 mL L−1) during 6 days. Gas production stopped when the pH dropped to about 4. The gas composition at different ratios consisted mainly of H2 (29–37%) and CO2 (34–35%) along with a minor fraction of N2 (10–21%) and O2 (2–4%). No methane (CH4) was observed in any co-culture under experimental conditions. Considering the exceptional inverse relation in H2 production and O2 consumption, algae-activated sludge correlation leads to substantial improvement in the H2 gas production compared to previous studies using pure bacterial cultures.

Original languageEnglish
Article number102649
JournalAlgal Research
Volume63
DOIs
Publication statusPublished - Apr 2022

Keywords

  • Activated sludge bacteria
  • Chlorella vulgaris
  • Co-culture
  • Green algae
  • Hydrogen production
  • Oxygen reduction

ASJC Scopus subject areas

  • Agronomy and Crop Science

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