Abstract

A halotolerant microalga was isolated from the Great Salt Lake (GSL), Utah, and was characterized through microscopic and genetic analysis as a cyanobacterium related to the Order Oscillatoriales, a Cyanophyceae that was capable of being cultivated on produced water wasted from the oil and gas extraction industry that produces 14 billion gallons annually in the U.S. that is costly to treat. On average for every barrel of crude oil generated, seven barrels of produced water are generated that contain high salinity and organic chemicals. The cyanobacterium was cultivated using a Rotating Algae Biofilm Reactor (RABR) constructed of a cotton cloth cylinder 19cm in diameter and 70cm long rotated at 1rpm into and out of 175 liters of produced water in a temperature controlled greenhouse to expose the microalga to diurnal sunlight from 0–900umolm^-2s^-1 and atmospheric CO₂ to cultivate the microalga as a biofilm. Hydrothermal liquefaction was used to transform the harvested biofilm into biocrude oil. Results from Hydrothermal Liquefaction (HTL) showed an average biocrude yield of 34.9% with values of energy content of biocrude at 40MJ/Kg and of microalgae at 14MJ/Kg. This research provides a methodology to utilize fossil fuel industry wastes to contribute to the biofuel industry using halotolerant microalgae.

Keywords:Biomarkers; Ecotoxicology; Cyanobacterium; Produced water; Hydrothermal Liquefaction; Algae biofilm