Methane, a powerful greenhouse gas, can be captured and transformed into protein-rich feed for farmed fish — an increasingly important food sector. A new analysis shows how to make the approach more cost-effective than current fish feeds.

«Industrial sources in the U.S. are emitting a truly staggering amount of methane, which is uneconomical to capture and use with current applications,» said study lead author Sahar El Abbadi, who conducted the research as a graduate student in civil and environmental engineering.

«Our goal is to flip that paradigm, using biotechnology to create a high-value product,» added El Abbadi, who is now a lecturer in the Civic, Liberal and Global Education program at Stanford.

Two problems, one solution

Although carbon dioxide is more abundant in the atmosphere, methane’s global warming potential is about 85 times as great over a 20-year period and at least 25 times as great a century after its release. Methane also threatens air quality by increasing the concentration of tropospheric ozone, exposure to which causes an estimated 1 million premature deaths annually worldwide due to respiratory illnesses. Methane’s relative concentration has grown more than twice as fast as that of carbon dioxide since the beginning of the Industrial Revolution due in great part to human-driven emissions.

A potential solution lies in methane-consuming bacteria called methanotrophs. These bacteria can be grown in a chilled, water-filled bioreactor fed pressurized methane, oxygen and nutrients such as nitrogen, phosphorus and trace metals. The protein-rich biomass that results can be used as fishmeal in aquaculture feed, offsetting demand for fishmeal made from small fish or plant-based feeds that require land, water and fertilizer.

Story Source:
Materials provided by Stanford University. Original written by Rob Jordan. Note: Content may be edited for style and length.