Consequences of drought stress on biofuels

September 7, 2017
From field to fuel. The switchgrass conversion process. Credit: Matthew Wishiewski

Plant-derived sustainable fuel sources could contribute to near-term U.S. energy security and independence. However, weather conditions could greatly affect crop yields. In this study, researchers examined the effect of weather on biofuel production by comparing switchgrass and corn stover harvested after a year of major drought and after 2 years of normal precipitation. They found that the plants produced more sugar, but the sugar changed during pretreatment and produced toxic compounds rather than the desired fuels.

The study is the first linking changes in rainfall and other conditions during crop growth to potential detrimental effects on biofuels. The work underscores the need to develop production systems that can tolerate sugars produced under stress and turn those sugars into the desired biofuels.  

In response to the 2012 severe Midwestern drought, soluble accumulated in switchgrass at significantly in comparison to non-drought years. The sugars were chemically changed during the pretreatment stage, the step that opens up the physical structure of the plant cell wall. The soluble sugars chemically changed by reacting with the ammonia-based pretreatment chemicals to form highly known as imidazoles and pyrazines. The formation of toxic compounds during the pretreatment stage inhibited conversion, the final step where intermediates such as sugars are fermented into biofuel by microorganisms, such as the microbe S. cerevisiae.

However, it may be possible to overcome this issue by 1) removing the soluble sugars before pretreatment or 2) using microbial strains resistant to the toxic effects of imidazoles and pyrazines. This study demonstrates that while there are benefits to growing bioenergy crops on marginal lands to avoid competition with food crops, the plants grown there may experience higher levels of stress resulting in deleterious impacts on microbes during . To develop sustainable biofuel , the deleterious effects of stress, such as fluctuations in precipitation and water availability, must be mitigated. This research helps to provide an understanding of the effects of drought stress on switchgrass.

Explore further: Microbe produces ethanol from switchgrass without pretreatment

More information: Rebecca Garlock Ong et al. Inhibition of microbial biofuel production in drought-stressed switchgrass hydrolysate, Biotechnology for Biofuels (2016). DOI: 10.1186/s13068-016-0657-0

Related Stories

Microbe produces ethanol from switchgrass without pretreatment

April 13, 2015

The conventional strategy for producing ethanol from plant biomass requires costly pretreatment and enzyme-driven reactions. Refining another strategy known as consolidated bioprocessing (CPB) could reduce costs. In second-generation ...

Decoded microbial metabolism explains biofuel yield

January 18, 2017

To unravel how intricate waste biomass converts to biofuels, a Cornell professor studied the bacterium Clostridium acetobutylicum to decipher its metabolism. Understanding the bacterium's sugar-processing complexities may ...

Metabolic path to improved biofuel production

March 4, 2015

Researchers with the Energy Biosciences Institute (EBI), a partnership that includes the Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley, have found a way to increase the ...

Recommended for you

Tasmanian tiger doomed long before humans came along

December 12, 2017

The Tasmanian tiger was doomed long before humans began hunting the enigmatic marsupial, scientists said Tuesday, with DNA sequencing showing it was in poor genetic health for thousands of years before its extinction.

Searching for the CRISPR Swiss-army knife

December 12, 2017

Scientists at the University of Copenhagen, led by the Spanish Professor Guillermo Montoya, are investigating the molecular features of different molecular scissors of the CRISPR-Cas system to shed light on the so-called ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.