Enhancing lead tolerance in spirulina using glycine betaine under high CO2 and salinity for sustainable carbon capture

[Geoengineering News]

https://www.sciencedirect.com/science/article/abs/pii/S0960852424014615

Authors

Chunli Yu, Rui Xu, Shengxi Shao, Wenguang Zhou 

06 November 2024

https://doi.org/10.1016/j.biortech.2024.131757

Highlights

•GB boosts spirulina biomass under seawater salinity, CO2 (15%), and lead exposure.

•GB enhances photosynthetic pigments and Fv/Fm for carbon fixation efficiency

•GB reduces EPS & DOM with decreased intracellular/extracellular lead accumulation.

•GB regulates genes involved in photosynthesis, oxidative stress, and ion transport.

Abstract

Microalgae-based carbon capture and utilization (CCU) offers a promising negative emission technology that absorbs CO2 and generates valuable biomass. However, heavy metal pollutants in industrial flue gases can compromise carbon sequestration efficiency and bioproduct quality. Spirulina was investigated as a model organism for CO2 sequestration, using a modified Zarrouk’s medium to integrate salt stress and an osmoprotectant to boost biomass yield under 15 % CO2. This approach enhances both biomass yield （380.83 mg L–1 d–1）and resistance to lead toxicity. Analytical assessments revealed that glycine betaine (GB) supplementation drastically reduced lead accumulation, decreasing the extracellular and intracellular contents by 39.7 % and 60.7 %, respectively. A notable decrease in extracellular dissolved organic matter was also observed. Furthermore, transcriptomic analyses confirmed that GB treatment strengthened osmotic stress responses and suppressed metal ion transport. These findings enhanced the feasibility of microalgae-based CCU technologies, marking significant progress in sustainable algal biotechnology.

Source: ScienceDirect