Why does Algae Biomass Need to be Constantly Circulated for Maximum Biomass Yield?

Just as humans breathe and eat to stay alive and healthy, algae also require constant circulation and nutrient exchange for optimal growth and productivity. This continuous process exposes the living biomass to more nutrients and helps in the rapid removal of waste products, ensuring the health and productivity of the algae.

Despite the numerous advantages of algae biomass, it will likely not overtake wind and solar as a major commercial biomass source. Wind and solar power have become so cost-effective that utility-scale farms, whether wind or solar, are cheaper than all fossil and nuclear energy sources worldwide. Solar and wind farms are also more economical than geothermal and hydroelectric power generation, although it is hoped that these sources are not phased out as quickly as fossil and nuclear energy sources.

Energy Efficiency and Misconceptions in Biomass Utilization

Correcting misconceptions about energy utilization is crucial for addressing the current challenges. Misunderstanding the efficiency of biomass like wood to energy can have significant negative impacts. For example, a scientist who spent decades promoting wood to energy based on an inaccurate assumption of efficiency ended up causing misleading research and justifying expensive conversion costs for a power plant that was not viable. Such mistakes are unfortunately common and more frequent than the correct analyses by informed researchers.

Optimized Growth through Continuous Circulation

Bathing agitation ensures that there is a constant and improved exchange of nutrients and metabolic wastes at the outer cell wall surfaces of the organisms producing biofuels or biofuel precursor chemicals. This process facilitates faster growth and multiplication of the organisms and can enhance the productivity of lipids. Additionally, it helps bring cells to the bath surface periodically for maximum light absorption, further enhancing growth.

In a raceway system, mature cells can be removed for processing to recover lipids, which is beneficial for product recovery. Once the cells are mature, they are recycled into nutrients for the entire bath, optimizing the resource use and enhancing efficiency.

Continuous Flow Stirred Tank Reactors (CFSTR)

In a non-raceway stirred tank known as a Continuous Flow Stirred Tank Reactor (CFSTR), the nutrient solution flows in, and an equal volume of cells of all maturities must flow out for processing. This means that the resources spent on processing are distributed across less mature cells, which have a lower mean lipid fraction. However, in LED artificial lighting schemes, it might make more sense to balance the input and output for optimal productivity.

Continuous circulation of algae biomass is thus essential for achieving and maintaining maximum yield in algae-based biofuels and other bio-products. Proper management of nutrient exchange and light absorption ensures the long-term sustainability and effectiveness of such systems.