Hydrogen photoproduction by nutrient-deprived Chlamydomonas reinhardtii cells immobilized within thin alginate films under aerobic and anaerobic conditions
✍ Scribed by Sergey N. Kosourov; Michael Seibert
- Book ID
- 101721116
- Publisher
- John Wiley and Sons
- Year
- 2009
- Tongue
- English
- Weight
- 316 KB
- Volume
- 102
- Category
- Article
- ISSN
- 0006-3592
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✦ Synopsis
Abstract
A new technique for immobilizing H~2~‐photoproducing green algae within a thin (<400 µm) alginate film has been developed. Alginate films with entrapped sulfur/phosphorus‐deprived Chlamydomonas reinhardtii, strain cc124, cells demonstrate (a) higher cell density (up to 2,000 µg Chl mL^−1^ of matrix), (b) kinetics of H~2~ photoproduction similar to sulfur‐deprived suspension cultures, (c) higher specific rates (up to 12.5 µmol mg^−1^ Chl h^−1^) of H~2~ evolution, (d) light conversion efficiencies to H~2~ of over 1% and (e) unexpectedly high resistance of the H~2~‐photoproducing system to inactivation by atmospheric O~2~. The algal cells, entrapped in alginate and then placed in vials containing 21% O~2~ in the headspace, evolved up to 67% of the H~2~ gas produced under anaerobic conditions. The results indicate that the lower susceptibility of the immobilized algal H~2~‐producing system to inactivation by O~2~ depends on two factors: (a) the presence of acetate in the medium, which supports higher rates of respiration and (b) the capability of the alginate polymer itself to effectively separate the entrapped cells from O~2~ in the liquid and headspace and restrict O~2~ diffusion into the matrix. The strategy presented for immobilizing algal cells within thin polymeric matrices shows the potential for scale‐up and possible future applications. Biotechnol. Bioeng. 2008. Biotechnol. Bioeng. 2009;102: 50–58. © 2008 Wiley Periodicals, Inc.