Photocatalyst-mineralized biofilms as living bio-abiotic interfaces for single enzyme to whole-cell photocatalytic applications

Abstract

There is an increasing trend of combining living cells with inorganic semiconductors to construct semi-artificial photosynthesis systems. Creating a robust and benign bio-abiotic interface is key to the success of such solar-to-chemical conversions but often faces a variety of challenges, including biocompatibility and the susceptibility of cell membrane to high-energy damage arising from direct interfacial contact. Here, we report living mineralized biofilms as an ultrastable and biocompatible bio-abiotic interface to implement single enzyme to whole-cell photocatalytic applications. These photocatalyst-mineralized biofilms exhibited efficient photoelectrical responses and were further exploited for diverse photocatalytic reaction systems including a whole-cell photocatalytic CO 2 reduction system enabled by the same biofilm-producing strain. Segregated from the extracellularly mineralized semiconductors, the bacteria remained alive even after 5 cycles of photocatalytic NADH regeneration reactions, and the biofilms could be easily regenerated. Our work thus demonstrates the construction of biocompatible interfaces using biofilm matrices and establishes proof of concept for future sustainable photocatalytic applications.

Engineered Living Materials For Sustainability

“…Thus, more research has turned to chemoheterotrophic bacteria to develop hybrid living systems that can easily tailor product diversity from CO 2 reduction. 437,439,440 For example, Guo et al employed the genetically modified workhorse S. cerevisiae and light-harvesting InP nanoparticles to create a bioinorganic hybrid system (Figure 28d). 437 The yeast can collect and employ electrons from the illuminated semiconductors to regenerate intracellular redox cofactors, facilitating the production of the downstream metabolite shikimic acid (Figure 28e).…”

Living electronics: A catalogue of engineered living electronic components

“…In addition to being capable of natively biomineralizing photoactive nanomaterials, microbes have also been engineered to act as scaffolds for the abiotic formation of photoactive semiconductor networks. Recently, Wang et al engineered E. coli to produce curli fibres with transition metal binding sites (Wang, Zhang, et al, 2022 ). This then allowed photoactive CdS nanoparticles to spontaneously form along the fibres when Cd 2+ and S 2− ions were introduced to the cell culture.…”

“…When formed on the working electrode surface of a three‐electrode bioreactor setup, the cell and curli fibre scaffold network of CdS was shown to produce a photocurrent upon illumination with blue light. This system was also leveraged for the development of an artificial photosynthesis scheme in which electrons generated by the photoexcitation of the CdS‐cell network were used to drive enzymatic chemical production (Wang, Zhang, et al, 2022 ). One limitation of using such semiconducting nanoparticles is the need for sacrificial electron donors (often exogenously supplied cysteine or unspecified cellular metabolites) to fill holes generated during semiconductor photoexcitation.…”

Endowing cells with unnatural photocatalytic ability for sustainable chemicals production by bionic minerals-triggering

“…[2][3][4][5][6] Notably, whole-cell photocatalytic biohybrid systems with self-replicating and self-repairing properties exhibit high performance and operational stability under the protection of a cell environment. [7][8][9][10][11] For example, whole-cell-based photosynthetic biohybrid systems have been constructed by combining nitrogenases or hydrogenases in cells with implanted quantum dots (InP/ZnSe, CdS, CdSe, etc.) to enhance solar-to-chemicals production.…”