Mathematics for streamlined biofuel production from unicellular algae

One of the greatest challenges of this century is to employ nature’s resources to address the world’s energy, food, water and chemical requirements without further unsettling the potentially precarious environmental balance in which we live. The recent resurgence of interest in green algae for biotechnological applications, such as bioenergy, carbon capture and pharmaceuticals, means it is vital that we understand the dynamics of suspensions of living cells. It is widely appreciated that mathematics can aid the optimization of the production of biofuels from algae. However, less obviously, mathematics can reveal mechanisms associated with the fact that many species of unicellular algae swim, and do so in preferred directions in response to environmental cues. Accumulations of cells can induce macroscale hydrodynamic instabilities due to their buoyancy, called bioconvection. There are immediate consequences for algal photobioreactor design, such as methods for cell harvesting, avoiding biofouling and understanding cellular dispersion in pipe flow.