The core of the research presented in this dissertation consists of using solar energy to renewably drive the conversion of CO2 and N2 to value-added chemicals, materials, feedstocks, and fuels. Nature has provided a blueprint for capturing and storing solar energy in chemical bonds through photosynthesis. However, our energy demands realistically outmatch the short-term capability of this natural process. Meanwhile, the solar capture ability of semiconductor materials outpaces that of biological organisms. Through my work I have developed photosynthetic biohybrid systems combining the solar capture of semiconductor nanomaterials and the selectivity and low substrate activation of whole cell “living” biocatalysts. Chapter 1 lays out the current state of the field and how it has evolved from the first demonstrations combining semiconductor materials with whole-cell biocatalysts for CO2 fixation. In Chapter 2 I describe an approach to improve the interface between light-active silicon nanowires and Sporomusa ovata (S. ovata), an electrophilic bacterium that converts CO2 into multi-carbon acetate. The silicon nanowires function as a cathode within an electrochemical cell allowing for a superior interface with the bacterial biocatalysts. S. ovata take up electrons at the cathode interface to jumpstart their native CO2 fixing metabolism. Although considerable efforts have been invested to optimize microorganism species and electrode materials separately, the microorganism-cathode interface has not been systematically studied as a function of operational parameters including applied electrochemical potential, electrolyte composition and biocatalyst loading. We found that as a more negative electrochemical potential was applied to an unoptimized system, the CO2-reducing current plateaued resulting from a fragmented bioinorganic interface as the bacteria broke away due to increasing local pH. By mitigating the pH change at the cathode-bacteria interface, we achieved a direct CO2 bioelectrosynthesis current density of 0.65 mA cm-2 with an ~80% faradaic efficiency. Furthermore, when powered with solar light, our platform attained a 3.6% solar-to-chemical efficiency. Acetate represents a valuable multi-carbon product because it can be readily used as a feedstock for a secondary bacterium. By carefully selecting a downstream microorganism, we achieved a broader biomanufacturing platform where acetate serves as a universally upgradeable cornerstone. In Chapter 3, I demonstrate that acetate, the primary product of the nanowire-bacteria biohybrid system, can be used as a feedstock for a secondary bacterial biocatalyst that upgrades the acetate to a biopolyester. This proof-of-concept consists of fueling the generation of biopolymer polyhydroxybutyrate (PHB) by Cupriavidus basilensis with CO2-derived acetate Our bioprocess enables the complete conversion of CO2 to PHB which is to be spun into 3D printing filament material. Although this demonstration contextualizes the ability to upgrade acetate to a material for additive manufacturing, the production rate is too low for successful industrial scaling. Through modeling of the bioprocess, we uncovered the reaction bottleneck to the be the H2 mass transfer from the gas phase to the liquid phase during autotrophic cultivation of S. ovata with CO2 and H2, as reducing substrate. By increasing the H2 mass transfer modestly, the time required to produce the equivalent mass of acetate would decrease by 75%. Furthermore, adapting the design to a flow cell platform would increase productivity two-fold and limit pH imbalances caused by acetate acidification. The sequential biocatalysis approach enables the straightforward downstream conversion of the initial CO2 product acetate to a higher value chemical, fuel, or material by a secondary bacterium. In Chapter 4, I report an advance on this concept by expanding the bioelectrosynthesis beyond CO2 reduction to include N2 reduction. We directly co-culture primary CO2-fixing S. ovata producing acetate with a secondary N2-fixing bacteria in Rhodopseudomonas palustris (R. palustris) that uses the acetate to both fuel N2 fixation and for the generation of a biopolyester. We demonstrate that the co-culture platform provides a robust ecosystem for continuous CO2 and N2 fixation where its outputs are directed by substrate gas composition. Moreover, we show the ability to support the co-culture on a high surface-area silicon nanowire cathodic platform. The biohybrid co-culture achieved peak faradaic efficiencies of at least 100, 19.1, and 6.3% for acetate, nitrogen in biomass and ammonia respectively while maintaining product tunability. Ultimately, this work demonstrates the ability to employ and electrochemically manipulate bacterial communities on demand to expand the suite of CO2 and N2 bioelectrosynthesis products. There are several advantages of bioelectrochemical CO2 fixation over the purely inorganic approach. Bioelectrochemical CO2 fixation offers products that are inaccessible to inorganic electrocatalysis, lower substrate activation energy translating to small overpotentials and the catalysts are self-regenerating and self-repairing. However, inorganic electrocatalysis reduces CO2 at rates that are orders of magnitudes higher. In Chapter 5 I lay out a roadmap to further combine the best attributes of electrocatalysis and the biologically mediated approach. CO2 was electrochemically converted to glycolaldehyde using a copper nanoparticle decorated cathode. Glycolaldehyde served as the key autocatalyst for the formose reaction, where it was combined with formaldehyde in the presence of an alkaline earth metal catalyst to form a variety of C4 - C8 sugars, including glucose. In turn, these sugars were used as a feedstock for fast-growing and genetically modifiable Escherichia coli. By electrocatalytically generating sugars, a high-energy bacterial feedstock, from CO2 we open the door to biomanufacturing with metabolically rapid and flexible microorganism. There are several obstacles to overcome but we introduce a roadmap to push the boundaries of product complexity achievable from CO2 conversion while demonstrating CO2 integration into life-sustaining sugars.