Scientists engineer sugarcane to produce lipids for biodiesel, more sugar for ethanol; ARPA-E project PETROSS
A multi-institutional team led by the University of Illinois has genetically engineered sugarcane to produce lipids in its leaves and stems for biodiesel production (lipid-cane). Surprisingly, the modified sugarcane plants also produced more sugar, which could be used for ethanol production.
The dual-purpose bioenergy crops are predicted to be more than five times more profitable per acre than soybeans and two times more profitable than corn. More importantly, sugarcane can be grown on marginal land in the Gulf Coast region that does not support good corn or soybean yields. A paper describing the work is published in the journal Biocatalysis and Agricultural Biotechnology.
The paper analyzes the project’s first genetically modified sugarcane varieties. Using a juicer, the researchers extracted about 90% of the sugar and 60% of the oil from the plant; the juice was fermented to produce ethanol and later treated with organic solvents to recover the oil. The team has patented the method used to separate the oil and sugar.
We expected that as oil production increased, sugar production would decrease, based on our computer models. However, we found that the plant can produce more oil without loss of sugar production, which means our plants may ultimately be even more productive than we originally anticipated.—Stephen Long, Gutgsell Endowed Professor of Plant Biology and Crop Sciences
Long leads the research project Plants Engineered to Replace Oil in Sugarcane and Sweet Sorghum (PETROSS) that has pioneered this work at the Carl R. Woese Institute for Genomic Biology at Illinois. The PETROSS project and this work are supported by the Advanced Research Projects Agency-Energy (ARPA-E).
The team recovered 0.5 and 0.8 percent oil from two of the modified sugarcane lines—67% and 167% more oil than unmodified sugarcane, respectively.
The oil composition is comparable to that obtained from other feedstocks like seaweed or algae that are being engineered to produce oil.—Vijay Singh, Director of the Integrated Bioprocessing Research Laboratory at Illinois
To date, PETROSS has engineered sugarcane with 13% oil, 8% of which is the oil (triacylglycerols) that can be converted into biodiesel. According to the project’s economic analyses, plants with just 5 percent oil would produce an extra 123 gallons of biodiesel per acre than soybeans and 350 more gallons of ethanol per acre than corn.
Currently, the project is seeking commercial investors to achieve 20% oil production—the theoretical limit according to the project’s computer models.
Co-authors of the paper include: Haibo Huang (Virginia Polytechnic Institute and State University); Robert A. Moreau (USDA/ARS); Michael J. Powell (USDA/ARS); Zhaoqin Wang (University of Illinois); Baskaran Kannan (University of Florida); Fredy Altpeter (University of Florida), and Aleel K. Grennan (University of Illinois).
Haibo Huang, Robert A. Moreau, Michael J. Powell, Zhaoqin Wang, Baskaran Kannan, Fredy Altpeter, Aleel K. Grennan, Stephen P. Long, Vijay Singh (2017) “Evaluation of the quantity and composition of sugars and lipid in the juice and bagasse of lipid producing sugarcane” Biocatalysis and Agricultural Biotechnology, Volume 10, Pages 148-155 doi: 10.1016/j.bcab.2017.03.003