To further explain this phenomenon, we returned to Figure and noted that the cell mass to OD ratio is increased in the pstSCAB mutant. We then hypothesized that the density of the individual cells may be increased. A previous study used a CsCl2 density gradient to measure individual cell density of algal biomass, where bands of ice cold CsCl2 at increasing concentrations are carefully layered in a tube to keep density regions distinct. Culture is then layered on top and centrifuged gently, causing the cells to settle at the interface between two density layers. In Figure , each layer is labeled and colored with alternating dyes for visibility. Wild type and PIT+ biomass behaved similarly and settled at the interface between 1.49g/L and 1.56g/L. However, PST+ biomass pelleted fully, meaning the density of the biomass is greater than the highest density measured of 1.73g/L. Settling velocity and density are primarily important variables for the first step of the dewatering train, passive dewatering via lamella clarifier. These are settling tanks with specialized geometry to separate culture into a clean water stream and biomass enriched stream, and their design depends on the settling velocity of the particles in solution. We can estimate particle settling via Stoke's velocity formula, and assuming cell size and culture viscosity are unchanged, the lower limit density values observed correspond to a 49% increase in estimated settling velocity. As lamella clarifiers are assumed to scale linearly in size with settling velocity, this corresponds to a 49% decrease in the size of clarifier required, reducing TCI and land area of the process. This estimate does not account for flocculation, which can occur naturally and increase settling velocity further, likely making this an underestimate of the true settling velocity and a slightly conservative overestimate of the dewatering cost.