Bacteria could hold key to carbon sequestration

Bacteria could offer a novel method of reducing atmospheric carbon dioxide, with researchers from the Lawrence Berkley National Laboratory's Center for Nanoscale Control of Geologic CO2 (NCGC) discussing various approaches at the 56th Annual Meeting of the Biophysical Society (BPS) in San Diego, California this week.

Their ideas involve pumping excess CO2 underground where it can mineralise with cations to create solid carbonate minerals, which effectively trap the gas permanently.
This is a slow process, over hundreds to thousands of years, but bacteria could help expedite the transformation.

Jenny Cappucio, who works on the project says, "Previous studies have shown that underground bacteria remain in the rock after CO2 injection. We know these microbes can impact how minerals form, leading us to wonder if they also affect the rate of mineralization. And if bacteria could enhance the nucleation of carbonate minerals, then perhaps we could fine-tune that ability in the laboratory."

The team has found that all bacteria enhance the rate of formation, but those microbes with an S-layer, or thin protein shell, increased the transformation rate the most. It is hoped that by fine tuning the deep subsurface microbes and increasing the negative charge on their surfaces, they will be able to increase the rate of carbonate nucleation, increasing the rate of carbon sequestration.

This could prove important for carbon sequestration projects, where the gas is simply pumped underground as a means of storage. Using bacteria could help make this process far more attractive to organisations previously against underground storage of carbon dioxide.