Identification of High Productivity Winter and Summer Season DISCOVR Strains in Climate-Simulation LEAPS Photobioreactors

During the first two years of DISCOVR project (fiscal years 2017 and 2018), nine (9) TIER II strains were evaluated in the PNNL LEAPS photobioreactors using a winter season climate-simulation script for January 31 at Mesa, AZ.  Mesa, AZ is the geographical location of the Arizona Center for Algae Technology and Innovation (AzCATI), and is the current Algae Biomass Productivity State of Technology (SOT) testbed site.  In addition, twelve (12) TIER II strains were evaluated in the LEAPS photobioreactor using a summer season climate-simulation script for July 1. 

Monoraphidium minutum 26B-AM exhibited the highest winter season biomass productivity (8.5 g/m2-day), followed by Micractinimum NREL 14-F2 (7.3 g/m2-day) in the winter LEAPS experiments (Figure 1). Both strains were tested at the PNNL Algae Testbed (PAT) in Arizona in early 2018, and Monoraphidium minutum 26B-AM was extensively pond-cultured during the 2018 spring and fall SOT campaigns at AzCATI.

The top two summer season strains were Nannochloris NREL 39-A8 (29.9 g/m2-day) and Scenedesmus obliquus UTEX393 (27.2 g/m2-day) (Figure 2) in the summer LEAPS experiments. The latter strain was tested in outdoor raceways at the PNNL Algae Testbed (PAT) during May 2018, and both strains were pond-cultured at AzCATI as part of the 2018 SOT campaign. The areal biomass productivity (29.9 g/m2-day) of the top summer season strain, Nannochloris NREL 39-A8, was 34% or 28 % greater than the SOT summer season benchmark strains Scenedesmus obliquus DOE0152.z (22.3 g/m2-day) or Chlorella sorokiniana DOE1412 (23.4 g/m2-day) in the LEAPS experiment, respectively.