Energize New Mexico
National Science Foundation
An algae polyculture (discovered in oil and gas produced water (PW) originating from a production facility in the Permian Basin of southwestern New Mexico) was composed primarily of Cyanobacterium aponinum, Parachlorella kessleri, with the remaining populations consisting of several species of halotolerant bacteria. The polyculture was tested in PW based media at a variety of different salinities and initial nutrient concentrations to determine the effects of these environmental conditions upon growth rate and lipid production. The polyculture exhibited growth rates of 45-50 mg AFDW/L/D in PW over a salinity range from 15 - 60 g total dissolved solids (TDS)/L in PW containing nitrate as a nitrogen source. Growth was reduced at higher salinity. Maximum lipid productivity (9 mg lipids/L/D) was achieved at 60 g TDS/L with up to 31% of the dry mass as lipids after nutrient depletion. The lipid content measured as fatty acid methyl ester (FAME) profiles at salinity levels of 15, 30, and 60 g TDS/L were dominated by palmitic (C16:0) and stearic (C18:0) acid. Biomass productivity (up to day 7) was higher with ammonium as the nitrogen source (48 - 58 mg AFDW/L/D) than nitrate, with the highest growth observed using initial concentrations of 13 mg NH4-N and 1.7 PO4-P/L (single day growth of 99 mg AFDW/L/D). Lipid productivity was highest at 60 g TDS/L when phosphorus was limiting (12 mg lipids/L/D), and the highest maximum lipid content was observed (47% of AFDW) with nitrogen limitation. Higher salinity, ammonium, and phosphate levels tended enriched for P. kessleri over C. aponinum, while the proportion of each species was more evenly mixed under other conditions. The results indicate that a mixed culture of C. aponinum and P. kessleri is a potential candidate for cultivation in brackish to hypersaline PW based media for the production of biomass and/or biofuels.
Schuler, Andrew. "Polyculture experiment growth, nutrient, and lipid measurements." (2018). https://digitalrepository.unm.edu/energizenm/683