Combining microfluidics and the natural photosynthetic membranes from spinach plants, researchers have developed "synthetic chloroplasts," which are capable of mimicking complex and life-like photosynthetic processes, a new study reports. "[The authors] demonstrate a major advancement in synthetic biology and a crucial milestone toward the construction of a self-sustaining synthetic cell," write Nathaniel Gaut and Katarzyna Adamala in a related Perspective. Photosynthetic carbon fixation is a fundamental biological process that uses light energy to convert inorganic carbon into the organic compounds required to sustain the vast majority of life on Earth. Thus, the ability to harness the near-limitless supply of light to provide anabolic energy to artificial living cells using photosynthetic-like processes is a highly sought-after goal in the effort to develop fully synthetic organisms. In nature, photosynthesis occurs in specialized organelles called chloroplasts, where enzyme complexes in thylakoid membranes convert light energy into adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide phosphate (NADPH), which are subsequently used to build organic molecules from inorganic carbon dioxide. However, the ability to engineer synthetic carbon fixing mechanisms that mimic complex natural photosynthetic processes in artificial systems remains elusive. Here, Tarryn Miller and colleagues integrate natural and synthetic biological parts to build chloroplast-mimicking microfluidic droplets that possess the essential characteristics of photosynthesis. Their approach uses microfluidics and natural thylakoid membranes from spinach to trigger light-driven complex biosynthetic tasks in synthetic, cell-sized droplets, including carbon fixation. According to the authors, the "synthetic chloroplast" micro-droplets can be programmed to achieve improved or new-to-nature photosynthetic processes with applications that range from small-molecule or drug synthesis to artificial biological systems for sequestering environmental carbon.
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Journal
Science