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Title: Photoproduction of Hydrogen by Sulfur-Deprived Chlamydomonas reinhardtii Mutants with Impaired Photosystem II Photochemical Activity

Abstract

Photoproduction of H2 was examined in a series of sulfur-deprived Chlamydomonas reinhardtii D1-R323 mutants with progressively impaired PSII photochemical activity. In the R323H, R323D, and R323E D1 mutants, replacement of arginine affects photosystem II (PSII) function, as demonstrated by progressive decreases in O2-evolving activity and loss of PSII photochemical activity. Significant changes in PSII activity were found when the arginine residue was replaced by negatively charged amino acid residues (R323D and R323E). However, the R323H (positively charged or neutral, depending on the ambient pH) mutant had minimal changes in PSII activity. The R323H, R323D, and R323E mutants and the pseudo-wild-type (pWt) with restored PSII function were used to study the effects of sulfur deprivation on H2-production activity. All of these mutants exhibited significant changes in the normal parameters associated with the H2-photoproduction process, such as a shorter aerobic phase, lower accumulation of starch, a prolonged anaerobic phase observed before the onset of H2-production, a shorter duration of H2-production, lower H2 yields compared to the pWt control, and slightly higher production of dark fermentation products such as acetate and formate. The more compromised the PSII photochemical activity, the more dramatic was the effect of sulfur deprivation on the H2-production process, whichmore » depends both on the presence of residual PSII activity and the amount of stored starch.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
915269
DOE Contract Number:
AC36-99-GO10337
Resource Type:
Journal Article
Resource Relation:
Journal Name: Photosynthesis Research; Journal Volume: 94; Journal Issue: 1, 2007
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; 59 BASIC BIOLOGICAL SCIENCES; ACETATES; AMINO ACIDS; ARGININE; CHLAMYDOMONAS; FERMENTATION; HYDROGEN; MUTANTS; PHOTOPRODUCTION; PRODUCTION; RESIDUES; STARCH; SULFUR; Basic Sciences

Citation Formats

Makarova, V. V., Kosourov, S., Krendeleva, T. E., Semin, B. K., Kukarskikh, G. P., Rubin, A. B., Sayre, R. T., Ghirardi, M. L., and Seibert, M. Photoproduction of Hydrogen by Sulfur-Deprived Chlamydomonas reinhardtii Mutants with Impaired Photosystem II Photochemical Activity. United States: N. p., 2007. Web. doi:10.1007/s11120-007-9219-4.
Makarova, V. V., Kosourov, S., Krendeleva, T. E., Semin, B. K., Kukarskikh, G. P., Rubin, A. B., Sayre, R. T., Ghirardi, M. L., & Seibert, M. Photoproduction of Hydrogen by Sulfur-Deprived Chlamydomonas reinhardtii Mutants with Impaired Photosystem II Photochemical Activity. United States. doi:10.1007/s11120-007-9219-4.
Makarova, V. V., Kosourov, S., Krendeleva, T. E., Semin, B. K., Kukarskikh, G. P., Rubin, A. B., Sayre, R. T., Ghirardi, M. L., and Seibert, M. Mon . "Photoproduction of Hydrogen by Sulfur-Deprived Chlamydomonas reinhardtii Mutants with Impaired Photosystem II Photochemical Activity". United States. doi:10.1007/s11120-007-9219-4.
@article{osti_915269,
title = {Photoproduction of Hydrogen by Sulfur-Deprived Chlamydomonas reinhardtii Mutants with Impaired Photosystem II Photochemical Activity},
author = {Makarova, V. V. and Kosourov, S. and Krendeleva, T. E. and Semin, B. K. and Kukarskikh, G. P. and Rubin, A. B. and Sayre, R. T. and Ghirardi, M. L. and Seibert, M.},
abstractNote = {Photoproduction of H2 was examined in a series of sulfur-deprived Chlamydomonas reinhardtii D1-R323 mutants with progressively impaired PSII photochemical activity. In the R323H, R323D, and R323E D1 mutants, replacement of arginine affects photosystem II (PSII) function, as demonstrated by progressive decreases in O2-evolving activity and loss of PSII photochemical activity. Significant changes in PSII activity were found when the arginine residue was replaced by negatively charged amino acid residues (R323D and R323E). However, the R323H (positively charged or neutral, depending on the ambient pH) mutant had minimal changes in PSII activity. The R323H, R323D, and R323E mutants and the pseudo-wild-type (pWt) with restored PSII function were used to study the effects of sulfur deprivation on H2-production activity. All of these mutants exhibited significant changes in the normal parameters associated with the H2-photoproduction process, such as a shorter aerobic phase, lower accumulation of starch, a prolonged anaerobic phase observed before the onset of H2-production, a shorter duration of H2-production, lower H2 yields compared to the pWt control, and slightly higher production of dark fermentation products such as acetate and formate. The more compromised the PSII photochemical activity, the more dramatic was the effect of sulfur deprivation on the H2-production process, which depends both on the presence of residual PSII activity and the amount of stored starch.},
doi = {10.1007/s11120-007-9219-4},
journal = {Photosynthesis Research},
number = 1, 2007,
volume = 94,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • No abstract prepared.
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  • A new technique for immobilizing H{sub 2}-photoproducing green algae within a thin (<400 {micro}m) 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 {micro}g Chl mL{sup -1} of matrix), (b) kinetics of H{sub 2} photoproduction similar to sulfur-deprived suspension cultures, (c) higher specific rates (up to 12.5 {micro}mol mg{sup -1} Chl h{sup -1}) of H{sub 2} evolution, (d) light conversion efficiencies to H{sub 2} of over 1% and (e) unexpectedly high resistance of the H{sub 2}-photoproducing system to inactivation by atmospheric O{sub 2}. The algal cells,more » entrapped in alginate and then placed in vials containing 21% O{sub 2} in the headspace, evolved up to 67% of the H{sub 2} gas produced under anaerobic conditions. The results indicate that the lower susceptibility of the immobilized algal H{sub 2}-producing system to inactivation by O{sub 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{sub 2} in the liquid and headspace and restrict O{sub 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.« less
  • We built a metabolic map of the hydrogen production process by the microalga Chlamydomonas reinhardtii, mathematically modeled this map in the S-systems formalism, then analyzed the effect of variations in the value of different model parameters on the overall response of the system. The mathematical model exhibited behavior similar to that described in literature for photosynthetic algal hydrogen production by sulfur-deprived algal cultures. This behavior consists of an initial phase during which oxygen is transiently generated and then consumed, followed by an anaerobic phase that is characterized by generation of hydrogen. Our analysis of the effect of independent variables onmore » the hydrogen production process mostly agrees with previous work [Horner J, Wolinsky M. A power-law sensitivity analysis of the hydrogen-producing metabolic pathway in Chlamydomonas reinhardtii. Int J Hydrogen Energy 2002;27: 1251-1255]. Moreover, a more detailed study of the effects of parameter modification (rate constants and kinetic order) indicated that genetic engineering of the hydrogenase expression, activity and stability may lead to increased performance of the process.« less
  • It is widely accepted that the primary electron acceptor in various Photosystem II (PSII) reaction center (RC) preparations is pheophytin {alpha} (Pheo {alpha}) within the D1 protein (Pheo{sub D1}), while Pheo{sub D2} (within the D2 protein) is photochemically inactive. The Pheo site energies, however, have remained elusive, due to inherent spectral congestion. While most researchers over the past two decades placed the Q{sub y}-states of Pheo{sub D1} and Pheo{sub D2} bands near 678-684 and 668-672 nm, respectively, recent modeling [Raszewski et al. Biophys. J. 2005, 88, 986-998; Cox et al. J. Phys. Chem. B 2009, 113, 12364-12374] of the electronicmore » structure of the PSII RC reversed the assignment of the active and inactive Pheos, suggesting that the mean site energy of Pheo{sub D1} is near 672 nm, whereas Pheo{sub D2} ({approx}677.5 nm) and Chl{sub D1} ({approx}680 nm) have the lowest energies (i.e., the Pheo{sub D2}-dominated exciton is the lowest excited state). In contrast, chemical pigment exchange experiments on isolated RCs suggested that both pheophytins have their Q{sub y} absorption maxima at 676-680 nm [Germano et al. Biochemistry 2001, 40, 11472-11482; Germano et al. Biophys. J. 2004, 86, 1664-1672]. To provide more insight into the site energies of both Pheo{sub D1} and Pheo{sub D2} (including the corresponding Q{sub x} transitions, which are often claimed to be degenerate at 543 nm) and to attest that the above two assignments are most likely incorrect, we studied a large number of isolated RC preparations from spinach and wild-type Chlamydomonas reinhardtii (at different levels of intactness) as well as the Chlamydomonas reinhardtii mutant (D2-L209H), in which the active branch Pheo{sub D1} is genetically replaced with chlorophyll {alpha} (Chl {alpha}). We show that the Q{sub x}-/Q{sub y}-region site energies of Pheo{sub D1} and Pheo{sub D2} are {approx}545/680 nm and {approx}541.5/670 nm, respectively, in good agreement with our previous assignment [Jankowiak et al. J. Phys. Chem. B 2002, 106, 8803?8814]. The latter values should be used to model excitonic structure and excitation energy transfer dynamics of the PSII RCs.« less