PhD graduate student Sarah Loftus was the top prize winner of the biology section at the Algae Biomass Summit. The Summit is the algae industry’s premier event, where leading producers of algae products go to network with industry suppliers and technology providers, where project developers converse with utility executives, and where researchers and technology developers rub elbows with venture capitalists. Ms. Loftus presented on recycled water use for industrial applications of algae. Congratulations!
Recycled algae cultivation water steadily accumulates dissolved organic carbon
Summary: Reusing cultivation water is required for economical and environmentally sustainable production of algal biofuels and co-products. However, recycled water contains compounds released by algae that can affect their growth. Previous studies have measured dissolved organic carbon (DOC) accumulation in recycled water, yet none have determined if recycled water affects DOC release or if DOC concentrations predict growth success in recycled water. Here, lab-scale water recycling experiments showed that different algae responded uniquely to recycled growth medium, but growth responses did not correlate with DOC concentration. DOC release rates were lower on average in recycled medium, although there was no trend of decreasing release rates across multiple water reuses. Accumulated DOC in recycled water was also not degraded, so at least a portion may be recalcitrant (i.e., non-biodegradable). Results can inform algae selection and cultivation decisions to maximize both the quality of recycled water and the carbon retained in algae biomass.