Photosynthetic prokaryotes evolved diverse light-harvesting (LH) antennas to absorb sunlight and transfer energy to reaction centers (RC). The filamentous anoxygenic phototrophs (FAPs) are important early branching photosynthetic bacteria in understanding the origin and evolution of photosynthesis. How their photosynthetic machinery assembles for efficient energy transfer is yet to be elucidated. Here, we report the 4.1 Å structure of photosynthetic core complex from Roseiflexus castenholzii by cryo-electron microscopy. The RC–LH complex has a tetra-heme cytochrome c bound RC encompassed by an elliptical LH ring that is assembled from 15 LHαβ subunits. An N-terminal transmembrane helix of cytochrome c inserts into the LH ring, not only yielding a tightly bound cytochrome c for rapid electron transfer, but also opening a slit in the LH ring, which is further flanked by a transmembrane helix from a newly discovered subunit X. These structural features suggest an unusual quinone exchange model of prokaryotic photosynthetic machinery.

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Microreactor technology shows great potential in the enhancement of liquid−liquid mass transfer, which is important especially when highly viscous fluids are involved. This provides an attractive way to intensify the extractive desulfurization (EDS) using ionic liquids (ILs) as an effective technique for ultralow-sulfur diesel production. This work concerns the extraction of dibenzothiophene in model diesel by [BMIM]PF 6 in a microchannel. The effects of the phase ratio and temperature on the hydrodynamics and mass transfer characteristics were investigated systematically. Higher temperature is beneficial for forming stable slug flow and droplet flow, as well as for increasing the overall mass transfer coefficient. The contributions of mass transfer during the droplet moving and forming stages were also discussed. Considerable mass transfer contribution (9−64% of the whole) was found during the droplet forming stage, and the mass transfer coefficient during the droplet moving stage can be well predicted by a two-film model.

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Gas–liquid–liquid three-phase flow systems have unique advantages of controlling reagent manipulation and improving reaction performance.

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