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Growing Engineered Algae Outdoors Shown Feasible, Safe

Algae growing tank

Outdoor tank growing genetically engineered algae (Erik Jepsen, Univ. of California in San Diego)

5 May 2017. A test of cultivating genetically engineered algae in outdoor tanks shows the production technique is feasible and does not pose risks to native algae populations. A report of this assessment by a team from University of California in San Diego and the company Sapphire Energy appears in the 3 May issue of the journal Algal Research (paid subscription required).

Algae is a fast-growing, inexpensive plant organism that grows wild, but can be also be cultivated as a crop. The plant grows in salt or wastewater, thus preserving fresh water sources, and requires few nutrients. Algae gets its energy from sunlight, and is a more efficient producer of biofuels than oil-based row crops, such as soybeans and corn. In addition, algae farms soak up carbon dioxide from the air, and can be sited near oil refineries or power plants to sequester CO2 emissions from those plants.

Genetically engineered algae can serve as a feedstock or raw material for products, such as biofuels, therapeutic proteins, Omega-3 fatty acids, and animal feeds, but the large-scale production of algae biomass requires large-scale facilities. And with those facilities out in the open, production costs are lower than putting the growing ponds in enclosed buildings. Cultivating genetically engineered algae outdoors, however, raises questions about the technique’s effects on native algae in the vicinity, as well as maintaining the desired traits in the engineered algae strains.

To answer these questions posed by the U.S. Environmental Protection Agency and others, researchers led by UC-San Diego molecular biologist Stephen Mayfield grew engineered algae in outdoor ponds and tracked the spread of the modified algae into other ponds at various distances from the original. Sapphire Energy, a biotechnology company in San Diego producing genetically-engineered algae, took part in the EPA-approved study. The university says the study is the first of its kind approved by the agency.

Mayfield and colleagues from the California Center for Algae Biotechnology, where he serves as director, and Sapphire Energy grew in large open ponds a common strain of algae, which they modified by adding a gene to improve synthesis of fatty acids and another gene to express a green fluorescent protein. After growing the engineered algae for 50 days, the team inspected other ponds in the vicinity designed to trap algae for evidence that the modified organisms spread to and colonized in those ponds.

The researchers found the engineered algae dispersed to trap ponds in the vicinity, but colonized only in those nearby the original source. Evidence of genetically engineered algae growing in other ponds declined quickly with increasing distance from the source. The team also found many wild types of local algae in the trap ponds after a few days. Inspections of five lakes in the region show the engineered algae had little if any effect on biodiversity and native algae strains than wild types of algae. In addition, the modified algae maintained its engineered traits during the 50-day test period.

The authors conclude that genetically modified algae can be grown outdoors, maintain its engineered traits, and not adversely affect native algae populations. “Just as agricultural experts for decades have used targeted genetic engineering to produce robust food crops that provide human food security,” says Mayfield in a university statement, “this study is the first step to demonstrate that we can do the same with genetically engineered algae.”

Sapphire Energy was founded in 2007 by Mayfield and others to develop genetically engineered algae for producing Omega-3 fatty acids, animal feeds, and renewable fuels. The company grows its algae in open ponds with non-potable water, such as sea water, and on non-arable land.

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