Engineered living photosynthetic biocomposites for intensified biological carbon capture

Abstract

Abstract Carbon capture and storage is required to meet Paris Agreement targets. Photosynthesis is nature’s carbon capture technology. Drawing inspiration from lichen, we engineered 3D photosynthetic cyanobacterial biocomposites (i.e., lichen mimics) using acrylic latex polymers applied to loofah sponge. Biocomposites had CO2 uptake rates of 1.57 ± 0.08 g CO2 g−1 biomass d−1. Uptake rates were based on the dry biomass at the start of the trial and incorporate the CO2 used to grow new biomass as well as that contained in storage compounds such as carbohydrates. These uptake rates represent 14–20-fold improvements over suspension controls, potentially scaling to capture 570 tCO2 t−1 biomass yr−1, with an equivalent land consumption of 5.5–8.17 × 106 ha, delivering annualized CO2 removal of 8–12 GtCO2, compared with 0.4–1.2 × 109 ha for forestry-based bioenergy with carbon capture and storage. The biocomposites remained functional for 12 weeks without additional nutrient or water supplementation, whereupon experiments were terminated. Engineered and optimized cyanobacteria biocomposites have potential for sustainable scalable deployment as part of humanity’s multifaceted technological stand against climate change, offering enhanced CO2 removal with low water, nutrient, and land use penalties.