This paper proposes a thermodynamic framework based on exergy and eco-exergy concepts
for biological hydrogen production from CO-enriched gas via a locally isolated
photosynthetic bacterium Rhodopseudomonas palustris PT. In order to achieve a deeper
understanding on the bioreactor performance, exergetic parameters like exergy destruction,
exergy efficiency, and sustainability index for the bioreactor were determined using
both concepts at different acetate concentrations as a carbon source ranging from 0 to 3 g/
L. The exergetic results based on both concepts remarkably diverged from each other due
to the inclusion of the work of information carried by the genomes of living organisms in
the eco-exergy concept. The sustainable dosage of sodium acetate was found to be 1.5 g/L
for efficient and eco-friendly bioconversion of harmful carbon monoxide to hydrogen and
carbon dioxide through the water-gas shift (WGS) reaction. The methodologies applied
herein revealed the benefits of applying exergy analysis for the design and optimization of
industrial-scale bioreactors to attain more cost-effective and eco-friendly biohydrogen
production. Consequently, the photobiological hydrogen production can be taken into
account as a sustainable alternative fuel to the non-renewable fossil resources by minimizing
the thermodynamics irreversibilities