Photosynthetic Biohydrogen Production In A Wastewater Environment And Its Potential As Renewable Energy

Keywords

Biohydrogen production; Hydrogenase; Oxygen regulation; Photo-algal hydrogen; Volatile fatty acids (VFAs)

Abstract

Oxygen (O2) is a strong inhibitor of hydrogenase (HydA) activity and expression and altering the sulfur (S) oxidizing transitions in photosystem II (PSII) often allows algal photohydrogen production; however, this may not be practical in a wastewater environment. To counteract natural mechanisms of oxygen evolution in PSII, we utilized acetic acid and butyric acid, which are main volatile fatty acids (VFAs) found in anaerobic bacterial digestion in wastewater treatment, as oxygen regulators for photosynthetic biohydrogen production using Chlorella vulgaris. It was found that a VFA-containing synthetic wastewater promotes oxygen depletion in a photobioreactor (PBR), producing maximum hydrogen yield of 65.4 ± 0.3 μmoL H2 L−1 mM−1 acetate without artificial sulfur or chloride deprivation. Butyric acids showed no significant effect on oxygen depletion and biohydrogen production in the PBR. The measurements of both relative expression level of mRNA and specific activities of reactivate HydA revealed that repetitive algal H2 photo-evolution was possible by HydA synthesis in C. vulgaris followed by complete oxygen depletion controlled by acetic acid levels in the PBR. This emerging understanding of the role of VFAs on oxygen regulation in PSII in natural environments is expected to lead algal-driven bioenergy production technologies to the next level.

Publication Date

4-15-2018

Publication Title

Energy

Volume

149

Number of Pages

222-229

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/j.energy.2018.02.051

Socpus ID

85042192171 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85042192171

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