Enhancing carbon neutrality: the role of biomass in CO₂ uptake

Globally, increasing greenhouse gas (GHG) emissions and increasing energy demand are refocusing attention on sustainable alternatives for fuels and chemicals. It is possible to achieve carbon neutrality through microalgae, forests, and crops since CO₂ uptake into their biomass is the primary hydrocarbon source. Since they uptake CO₂ through photosynthesis into biomass, as well as store it in the form of lipids, proteins, and carbohydrates during their growth phase, the biomass of lignocellulosic, microalgal, and agricultural crop residues can be used for chemicals and biofuels production. Their carbohydrates can be used as feedstock for bioethanol production, while their residual biomass can be used to produce bio-oil. As microalgae, forest trees, and crops grow, they capture almost the same amount of CO₂ released as biomass or fuel is burned, making their biomass a carbon-neutral energy source. This approach exploits biomass to mitigate CO₂ emissions while concurrently producing bioenergy. Using microalgae, a circular carbon economy will be enabled through biorefinery. This chapter explores whether the uptake of CO₂ into biomass is feasible and desirable for achieving carbon neutrality. Some trade-offs include biomass availability, GHG emissions, policies, the environment, biodiversity, land use, and food security.