Scalable Solar-Driven Chemical Production by Semiconductor Biohybrids Synthesized from Wastewater Pollutants

Abstract

Semiconductors biohybrids integrate the best of biological catalysts and semiconductor nanomaterials for solar-to-chemical conversion. To realize the potential of hybrid systems at the commercial level, it remains an urgent need for cost-competitive and environmentally friendly approaches to scaling up. Here, we successfully tackle this challenge through developing biohybrid route that co-utilize multi-pollutants in wastewater to produce semiconductor biohybrids in-situ for solar-to-chemical production. To achieve cost-effective biohybrid production, we introduced an aerobic sulfate reduction pathway into Vibrio natriegens to enable the direct utilization of the heavy metal ions (i.e., Cd2+), sulfate, and organics in the wastewater to biosynthesize functional semiconductor nanoparticles in living V. natriegens. Furthermore, 2,3-butanediol biosynthetic pathway was introduced into the V. natriegens hybrid to couple the solar energy for enhanced bioproduction. We demonstrated the scalability of this system in a 5-L illuminated fermenter using wastewater as the feedstock, which resulted in production of 13 g/L of 2,3-butanediol. Life cycle analysis showed this specific biohybrid route had a significantly lower cost and reduced CO2 emission compared to both pure sugars fermentation and fossil-based routes. In addition to providing a promising step toward sustainable commercializing semiconductor biohybrids for biomanufacturing, our work may lead to hybrid living matter toward future waste to wealth conversion.