Author(s): Erick Alvarez, Jonathan Kinross, Callie Ross, Pedro Rodriguez, Gerardo Acosta, Elise Bennett
Mentor(s): Colleen Hough, Eric T. Domyan
Institution UVU
Utah Lake is an important part of our valley, but its natural waters are plagued by harmful algal blooms otherwise known as “HABs”. These HABs break out across the state every summer, lasting well into the fall. The desert heat, nutrient-rich dust, and human activity are all contributing factors. With climate change lengthening the summers, there is seemingly no end to the season of blooms. The conservation of Utah Lake is not just a local issue, but also used worldwide as a standard example of cyanobacterial blooms. Excess nutrients entering Utah Lake lead to increased cyanobacterial blooms that produce toxins hazardous to human, animal, and aquatic life. The excess nutrients are composed mostly of nitrogen and phosphorous compounds that enter the lake primarily from wastewater treatment plants, runoff fertilizer, and naturally occurring inorganic resources. Our goal is to reduce the nutrient load of wastewater entering the lake by engineering a harmless organism to sequester phosphorus and convert nitrogenous compounds to atmospheric nitrogen, which is biologically inert. We chose the non-toxic green algae Chlamydomonas reinhardtii, also known as “Chlamy”, as the chassis for our genetically engineered machine. Chlamy naturally undergoes partial denitrification, converting nitrate to nitrous oxide, a potent greenhouse gas. It also naturally uptakes phosphate when starved of the nutrient and expels any excess. We have identified various genes, constructed a plasmid, and transformed our chassis with the aim of completing the denitrification pathway by reducing nitrous oxide into nitrogen gas using the nosZ gene. Therefore, nitrates will be removed from the water. This same plasmid also facilitates constitutive activation of the algae’s phosphate starvation response (Psr1) and the suppression of its release mechanism (Ptc1) via an originally designed artificial micro-RNA. By over-expressing Psr1 and shutting down the transport proteins encoded by Ptc1, the algae can sequester excess phosphorus and retain it within its cell, thus removing the nutrient from surrounding water along with nitrate. The project aims to deploy Bloom Buster, our modified algae, as a tertiary treatment within wastewater facilities. This would mitigate the potential of our green algae of entering the lake. The secondary, long-term goal is to turn the sequestered nutrients into a marketable product and regenerative fertilizer.