Semiconductor augmented hydrogen and polyhydroxybutyrate photosynthesis from Rhodospirillum rubrum and a mechanism study

Abstract

Photosynthetic biohybrid systems based on purple bacteria and semiconducting nanomaterials are promising platforms for sustainable solar-powered chemical production. However, these types of biohybrid systems have not been fully developed to...

Revisiting Solar Energy Flow in Nanomaterial-Microorganism Hybrid Systems

“…In addition to cyanobacterium and green algae, the purple bacterium R. palustris carrying mineralized nano-CdS has demonstrated elevated intracellular NADPH levels. This phenomenon is accompanied by increased accumulation of polyhydroxybutyrate (PHB) and biomass under photoheterotrophic growth conditions. , Similar observations have been made in another purple bacterium, CdS- R. rubrum . Both membrane-anchored mineralized nano-CdS and intracellular g-C 3 N 4 QDs have shown the capacity to enhance the anaerobic H 2 production of E. coli under visible light irradiation via upregulating its intracellular NADH levels. , Moreover, CdS nanoclusters can be mineralized within the periplasm of engineered E. coli , directly interfacing with the respiratory electron transport chain and leading to light-boosted ATP turnover .…”

“…These nanoparticles have surfaces that are partially or entirely exposed to the periplasm and/or cytoplasm, making them more likely to directly transport captured solar energy to intracellular enzymes compared to extracellularly localized nanomaterials. Hybrid systems featuring mineralized nanoparticles with cross-membrane anchoring include CdS- M. thermoacetica , ,, CdS- S. oneidensis , ,, CdS- E. coli , CdS- R. palustris , , CdS- T. denitrificans , CdS- G. sulfurreducens , CdS- M. barkeri , CdS- S. ovata , and CdS- R. rubrum . Nanomaterials, such as quantum dots (QDs), that are small enough can also enter and be confined in the periplasm through endocytosis. ,,, The specific endocytic pathway taken by the nanomaterials depends on their size and surface properties, and may proceed through phagocytosis, pinocytosis, macropinocytosis, or clathrin/caveolae-mediated endocytosis .…”

“…Illustrative instances encompass PFP- Synechococcus sp. , CdS- R. palustris , , CdS- R. rubrum , CdS- E. coli , InP- S. cerevisiae , and g-C 3 N 4 - E. coli . Therefore, in-depth investigations are required to unveil the unclear pathways of energy flow.…”

“…In addition to proposing systematic optimizations for current NMHSs, we also provide a comprehensive overview of contemporary techniques that can be employed to investigate various aspects of energy flow within NMHSs. The morphologies of nanomaterials, cells, and material-cell interfaces are typically characterized through scanning electron microscopy (SEM), ,,,,,,,,,,,, transmission electron microscopy (TEM) (refs , , , , , , , , , , , , , , and ), and atomic force microscopy (AFM). , Furthermore, the electrochemical/photoelectrochemical properties of NMHSs are frequently studied using techniques such as differential pulse voltammetry (DPV) , and cyclic voltammetry (CV), ,,,− often in conjunction with customizable illumination sources. The elucidation of charge separation and recombination in nanomaterials, as well as charge transfer at material-cell interfaces, is primarily achieved through techniques such as photoluminescence and time-resolved photoluminescence (PL/TRPL) spectroscopy, ,,,,,, transient absorption (TA) spectroscopy, ,,,, scanning electrochemical microscopy (SECM), , scanning tunneling microscopy (STM), and synchrotron X-ray radiation techniques. , Additionally, analytical methods like high-performance liquid chromatography (HPLC), , mass spectrometry (MS), and nuclear magnetic resonance (NMR) are available for the identification of unknown species in the reaction system, particularly those with suspected biological or electrochemical effects, such as energy carriers.…”

Synergistic Approaches for Enhanced Light-Driven Hydrogen Production: A Membrane-Anchoring Protein-Engineered Biohybrid System with Dual Photosensitizers Strategy

“…The efficient separation of photogenerated electrons and the establishment of an electron transfer pathway between intracellular EY and hydrogenase were observed in the Hyd-Tip@TiO 2 @EY biohybrid system. The electrochemical impedance spectroscopy (EIS) analysis determined the electron transfer rate by assessing the diameter of the semicircle. , A smaller diameter indicates a faster electron transfer rate, highlighting an inverse proportionality between the diameter of Hyd-Tip@TiO 2 @EY and the electron transfer rate (Figure i). In the Cyclic Voltammetry (CV) measurements, Hyd-Tip@TiO 2 @EY exhibited a higher peak current and better capacitive behavior, as evidenced by a more rectangular shape and higher areal capacitance values (Figure j).…”