PNNL

Abstract

To address major knowledge gaps and barriers to the commercial development of algal biomass for biofuels and co-products, a collaborative consortium, entitled Development of Integrated Screening, Cultivar Optimization, and Verification Research (DISCOVR), was established in 2016. This consortium is funded by the Bioenergy Technologies Office (BETO) of the U.S. Department of Energy (DOE) and constitutes a partnership between four DOE national laboratories - Pacific Northwest National Laboratory, Los Alamos National Laboratory, the National Renewable Energy Laboratory, and Sandia National Laboratories - and the Arizona Center for Algae Technology and Innovation (AzCATI) at Arizona State University. To address the barriers of strain selection for achieving high seasonal productivities with a suitable composition and culture resilience, the following tiered strain down-selection pipeline is used. At Tier I, the temperature and salinity tolerance of strains is determined in flask cultures; at Tier II, the areal biomass productivity and composition is determined in climate-simulation photobioreactors; at Tier III, the productivity and culture stability are determined in outdoor raceways. The top performing strains move forward to long-term testing at BETO’s State of Technology (SOT) testbed site at AzCATI to generate yearly data on annual biomass productivity and the respective minimum biomass selling price (MBSP). Concurrent to the strain down-selection in the DISCOVR pipeline, hypotheses for increasing biomass productivity, shifting biomass composition to enhance intrinsic value, and improving culture stability and resistance to pests are also tested. Techno-economic analyses are carried out to determine whether promising findings from laboratory studies or proposed modifications in outdoor pond cultivation conditions translate into reductions in MBSP. The impact of DISCOVR has been significant: in three years following the launch of DISCOVR, the annual biomass productivity has increased from 11.7 to 17.6 g m-2 day-1, a 50% gain, resulting in a concomitant decrease in MBSP from 824 to 611 $ ton-1, a 26% decline.