Evaluation of a green alga isolate for growth and lipid accumulation in coal bed methane water from the Powder River Basin

Abstract

Coal bed methane (CBM) production ponds are being constructed more frequently in areas such as the Powder River Basin in Montana and Wyoming where methane production has been active in the past decade. These ponds are currently not being utilized and are holding billions of gallons of water. The extracted water in these ponds is presently being discharged to local stream drainages or infiltrating into the surrounding soil. The environmental impacts of this increase in water can have negative effects on the surrounding areas. The purpose of this thesis is to explore the possibility of using CBM production ponds in the Powder River Basin, in Montana and Wyoming, for the growth of microalgae and the production of biodiesel from their accumulated lipids. Microalgae have been known to grow in other bodies of undesirable water and research has been ongoing on how to effectively use microalgae as a resource by stimulating lipid accumulation through the use of various environmental stressors. Coal bed methane ponds already provide a source of non-potable water for microalgae cultivation. Exploring the possibility of making these ponds a growth medium for microalgae is the first step in determining whether they can be turned into a productive energy resource. A native green alga, CBMW, has been isolated from a CBM production pond in northeastern Wyoming. CBMW has been cultured and grown under laboratory conditions in sterile CBM water and Bold's Basal Medium (BBM). Chlorophyll levels, biomass growth, pH, lipid accumulation, and water chemistry were tracked while CBMW was grown in sterile CBM water to understand how the alga responds to varying environmental conditions. When grown under the right environmental conditions isolate CBMW increased biomass and accumulated lipids. These results suggest that attempting to grow CBMW on a larger scale in CBM production water could be an effective method to produce biodiesel while utilizing a potentially problematic water source.