Glucose Synthesis in a Protein-Based Artificial Photosynthesis System
- 406 Downloads
The objective of this study was to understand glucose synthesis of a protein-based artificial photosynthesis system affected by operating conditions, including the concentrations of reactants, reaction temperature, and illumination. Results from non-vesicle-based glyceraldehyde-3-phosphate (GAP) and glucose synthesis showed that the initial concentrations of ribulose-1,5-bisphosphate (RuBP) and adenosine triphosphate (ATP), lighting source, and temperature significantly affected glucose synthesis. Higher initial concentrations of RuBP and ATP significantly enhanced GAP synthesis, which was linearly correlated to glucose synthesis, confirming the proper functions of all catalyzing enzymes in the system. White fluorescent light inhibited artificial photosynthesis and reduced glucose synthesis by 79.2 % compared to in the dark. The reaction temperature of 40 °C was optimum, whereas lower or higher temperature reduced glucose synthesis. Glucose synthesis in the vesicle-based artificial photosynthesis system reconstituted with bacteriorhodopsin, F 0 F 1 ATP synthase, and polydimethylsiloxane-methyloxazoline-polydimethylsiloxane triblock copolymer was successfully demonstrated. This system efficiently utilized light-induced ATP to drive glucose synthesis, and 5.2 μg ml−1 glucose was synthesized in 0.78-ml reaction buffer in 7 h. Light-dependent reactions were found to be the bottleneck of the studied artificial photosynthesis system.
KeywordsArtificial photosynthesis Bacteriorhodopsin Copolymer F0F1 ATP synthase Glucose synthesis
The authors wish to thank Drs. Masasuke Yoshida (Kyoto Sangyo University, Japan) and Toshiharu Suzuki (Hokkaido University, Japan) for the donation of F 0 F 1 ATP synthase. This work was financially supported by the US National Science Foundation (Award # CMMI-1266338; 1266306; 1300792; CBET-1438025; 1437930; 1437798) and the startup fund of North Carolina State University.
- 11.Huang, W. D. (2011). Synthesis of sugar and fixation of CO2 through artificial photosynthesis driving by hydrogen or electricity. Journal of University of Science and Technology of China., 41(5), 459–468.Google Scholar
- 16.Heyn, M. P., & Dencher, N. A. (1982). Reconstitution of monomeric bacteriorhodopsin into phospholipid vesicles. Enzyme in Enzymology, 88, 31–35.Google Scholar
- 27.Overly, C. C., Lee, K. D., Berthiaume, E., & Hollenbeck, P. J. (1995). Quantitative measurement of intraorganelle pH in the endosomal-lysosomal pathway in neurons by using ratiometric imaging with pyranine. Neurobioology, 92(8), 3156–3160.Google Scholar
- 28.Pitard, B., Richard, P., Dunach, M., Girault, G., & Rigaud, J. L. (1996). ATP synthesis by the F0F1 ATP synthase from thermophilic Bacillus PS3 reconstituted into liposomes with bacteriorhodopsin. 1. Factors defining the optimal reconstitution of ATP synthases with bacteriorhodopsin. European Journal of Biochemistry, 235(3), 769–778.CrossRefGoogle Scholar