Solar-powered production of biofuels and other petroleum substitutes by cyanobacteria

Stoichiometries of reducing equivalents and chemical energy, and energy conversion efficiency

Research output: Chapter in Book/Report/Conference proceedingChapter

3 Citations (Scopus)

Abstract

Cyanobacteria are a promising platform for solar-powered, CO2-consuming production of biofuels, petroleum substitutes, and other useful products using photosynthesis. Efficient production of such compounds requires that the stoichiometry of reducing equivalents (NADPH) and chemical energy (ATP) produced as a result of photosynthetic electron transport is well-matched by the stoichiometry of reducing equivalents and chemical energy required for production of the desired compounds. Here it is shown that stoichiometry requirements are met when producing compounds generated via the fatty acid or isoprenoid biosynthesis pathways. In the case of fatty acid production, the amount of energy stored in the fatty acid can be up to 28% of the energy of the light if one were to excite with 680 nm light and all absorbed light was used for fatty acid production. Making adjustments for solar illumination (only ∼50% of the energy can be used for photosynthesis), blue-photon utilization, and losses due to non-photochemical quenching and the requirements for maintenance energy, the solar energy conversion efficiency may still be in the range of ∼7%, which is superior to most other bio-based approaches. However, photohydrogen production that directly uses reducing equivalents from photosynthetic electron transfer for H2 production does not require ATP and thereby is not properly stoichiometrically balanced. An additional complexity of H2 production in relatively small cyanobacterial cells at somewhat alkaline pH is that the number of free protons in a cell is extremely limited (a few protons per cyanobacterial cell of 1 fL at pH 8.0). However, regardless the inherent difficulties of light-driven H2 production in cyanobacteria, the utilization of cyanobacteria for light-driven generation of carbon-based biofuels and related products can be efficient and is very promising.

Original languageEnglish (US)
Title of host publicationAdvanced Topics in Science and Technology in China
PublisherSpringer
Pages353-357
Number of pages5
DOIs
StatePublished - Jan 1 2013

Publication series

NameAdvanced Topics in Science and Technology in China
ISSN (Print)1995-6819
ISSN (Electronic)1995-6827

Fingerprint

Biofuels
Petroleum
Energy conversion
Stoichiometry
Conversion efficiency
Crude oil
Fatty acids
Fatty Acids
Photosynthesis
Adenosinetriphosphate
Protons
Adenosine Triphosphate
Cyanobacteria
Biosynthesis
Terpenes
NADP
Solar energy
Quenching
Carbon
Photons

Keywords

  • Cyanobacteria
  • Energy conversion efficiency
  • Solar-to-Fuel conversion
  • Stoichiometry

ASJC Scopus subject areas

  • Engineering(all)
  • Chemical Engineering(all)
  • General

Cite this

Solar-powered production of biofuels and other petroleum substitutes by cyanobacteria : Stoichiometries of reducing equivalents and chemical energy, and energy conversion efficiency. / Vermaas, Willem.

Advanced Topics in Science and Technology in China. Springer, 2013. p. 353-357 (Advanced Topics in Science and Technology in China).

Research output: Chapter in Book/Report/Conference proceedingChapter

Vermaas, Willem. / Solar-powered production of biofuels and other petroleum substitutes by cyanobacteria : Stoichiometries of reducing equivalents and chemical energy, and energy conversion efficiency. Advanced Topics in Science and Technology in China. Springer, 2013. pp. 353-357 (Advanced Topics in Science and Technology in China).
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