Sustainability

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GLBRC's Sustainability Research Area

Sustainability

Focusing on one attribute comes at a high price.

At the GLBRC, sustainability researchers are exploring complex issues in agricultural and industrial systems. Research focuses on understanding the attributes and mechanisms responsible for the environmental sustainability of biofuel production systems, such as environmental impacts — many of which may be positive — and socioeconomic factors including incentives and policy options

Learn about the Center's research approach

Sustainability Leadership

Scientific Director, Sustainability Lead

A crop and soil scientist and ecosystem ecologist, Robertson focuses much of his research on the role that agriculture plays in greenhouse gas dynamics, and he is internationally known for his expertise in this area. Robertson has been the director...

Sustainability Lead

Jackson’s program focuses on structure and function of managed, semi-natural and natural grassland ecosystems. Research in Jackson’s grassland ecology lab spans many levels of ecological organization, from grass identification at the DNA level to landscape diversity effects on alternative biofuels...

Project Overview

A device used for measuring plant utilization of solar radiation sits in front of plots of switchgrass, corn and poplar growing in the Great Lake Bioenergy Research Center's fields at the Arlington Agricultural Research Station in Arlington, WI.GLBRC Sustainability research ranges from the microbial community level to regional modeling, and researchers conduct fieldwork at different project sites to reflect this diversity of scale. Small plots at Kellogg Biological Station in Michigan and the Arlington Agricultural Research Station in Wisconsin provide locations for measurement-intensive experiments, while investigators work in larger scale-up fields to collect data on carbon balances and biogeochemical processes. Finally, researchers pursue ecosystem-level biodiversity questions across landscapes, including marginal lands, in central Michigan and Wisconsin.

Specific sustainability projects include:

  • Novel biofuel production systems
  • Microbial-plant interactions for improved biofuel production
  • Biogeochemical responses
  • Biodiversity responses
  • Economic responses
  • Modeling, design and testing of drop-in fuels
  • Process synthesis and technoeconomic evaluation for biomass-to-fuels technologies.

 

Sustainability Publications

Ecosystem water-use efficiency of annual corn and perennial grasslands: contributions from land-use history and species composition

Michael Abraha; Ilya Gelfand; Stephen K. Hamilton; Changliang Shao; Yahn-Jauh Su; Philip Robertson; Jiquan Chen

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2016

Carbon and water exchanges between vegetated land surfaces and the atmosphere reveal the ecosystem-scale water-use efficiency (WUE) of primary production. We examined the interacting influence of dominant plant functional groups (C3 and C4) and land-use history on WUEs of annual corn and perennial (restored prairie, switchgrass and smooth brome grass) grasslands in the US Midwest from 2010 through 2013. To this end, we determined ecosystem-level (eWUE) and intrinsic (iWUE) WUEs using eddy covariance and plant carbon isotope ratios, respectively. Corn, switchgrass, and restored prairie were each planted on lands previously managed as grasslands under the USDA Conservation Reserve Program (CRP), or as corn/soybean rotation under conventional agriculture (AGR), while a field of smooth brome grass remained in CRP management. The iWUEs of individual C3 plant species varied little across years. Corn had the highest (4.1) and smooth brome grass the lowest (2.3) overall eWUEs (g C kg−1 H2O) over the 4 years. Corn and switchgrass did not consistently show a significant difference in seasonal eWUE between former CRP and AGR lands, whereas restored prairie had significantly higher seasonal eWUE on former AGR than on former CRP land due to a greater shift from C3 to C4 species on the former AGR land following a drought in 2012. Thus, differences in grassland eWUE were largely determined by the relative dominance of C3 and C4 species within the plant communities. In this humid temperate climate with common short-term and occasional long-term droughts, it is likely that mixed grasslands will become increasingly dominated by C4 grasses over time, with higher yields and eWUE than C3 plants. These results inform models of the interaction between carbon and water cycles in grassland ecosystems under current and future climate and management scenarios.

Genome sequence and analysis of a stress-tolerant, wild-derived strain of Saccharomyces cerevisiae used in biofuels research

Sean J. McIlwain; David Peris; Maria Sardi; Oleg V. Moskvin; Fujie Zhan; Kevin S. Myers; Nicholas M. Riley; Alyssa Buzzell; Lucas S. Parreiras; Irene M. Ong; Robert Landick; Joshua J. Coon; Audrey P. Gasch; Trey K. Sato; Chris Todd Hittinger

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2016

The genome sequences of more than 100 strains of the yeast Saccharomyces cerevisiae have been published. Unfortunately, most of these genome assemblies contain dozens to hundreds of gaps at repetitive sequences, including transposable elements, tRNAs, and subtelomeric regions, which is where novel genes generally reside. Relatively few strains have been chosen for genome sequencing based on their biofuel production potential, leaving an additional knowledge gap. Here, we describe the nearly complete genome sequence of GLBRCY22-3 (Y22-3), a strain of S. cerevisiae derived from the stress-tolerant wild strain NRRL YB-210 and subsequently engineered for xylose metabolism. After benchmarking several genome assembly approaches, we developed a pipeline to integrate Pacific Biosciences (PacBio) and Illumina sequencing data and achieved one of the highest quality genome assemblies for any S. cerevisiae strain. Specifically, the contig N50 is 693 kbp, and the sequences of most chromosomes, the mitochondrial genome, and the 2-micron plasmid are complete. Our annotation predicts 92 genes that are not present in the reference genome of the laboratory strain S288c, over 70% of which were expressed. We predicted functions for 43 of these genes, 28 of which were previously uncharacterized and unnamed. Remarkably, many of these genes are predicted to be involved in stress tolerance and carbon metabolism and are shared with a Brazilian bioethanol production strain, even though the strains differ dramatically at most genetic loci. The Y22-3 genome sequence provides an exceptionally high-quality resource for basic and applied research in bioenergy and genetics.

How did nature engineer the highest surface lipid accumulation among plants? Exceptional expression of acyl-lipid-associated genes for the assembly of extracellular triacylglycerol by Bayberry (Myrica pensylvanica) fruits

Jeffrey P. Simpson; Nicholas Thrower; John B. Ohlrogge

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2016

Bayberry (Myrica pensylvanica) fruits are covered with a remarkably thick layer of crystalline wax consisting of triacylglycerol (TAG) and diacylglycerol (DAG) esterified exclusively with saturated fatty acids. As the only plant known to accumulate soluble glycerolipids as a major component of surface waxes, bayberry represents a novel system to investigate neutral lipid biosynthesis and lipid secretion by vegetative plant cells. The assembly of bayberry wax is distinct from conventional TAG and other surface waxes, and instead proceeds through a pathway related to cutin synthesis (Simpson and Ohlrogge, 2016). In this study, microscopic examination revealed that the fruit tissue that produces and secretes wax (bayberry knobs) is fully developed before wax accumulates and that wax is secreted to the surface without cell disruption. Comparison of transcript expression to genetically related tissues (bayberry leaves, M. rubra fruits), cutin-rich tomato and cherry fruit epidermis, and to oil-rich mesocarp and seeds, revealed exceptionally high expression of 13 transcripts for acyl-lipid metabolism together with down-regulation of fatty acid oxidases and desaturases. The predicted protein sequences of the most highly expressed lipid-related enzyme-encoding transcripts in bayberry knobs are 100% identical to the sequences from bayberry leaves, which do not produce surface DAG or TAG. Together, these results indicate that TAG biosynthesis and secretion in bayberry is achieved by both up and down-regulation of a small subset of genes related to the biosynthesis of cutin and saturated fatty acids, and also implies that modifications in gene expression, rather than evolution of new gene functions, was the major mechanism by which bayberry evolved its specialized lipid metabolism. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner.

Inhibition of microbial biofuel production in drought-stressed switchgrass hydrolysate

Rebecca G. Ong; Alan Higbee; Scott Bottoms; Quinn Dickinson; Dan Xie; Scott A. Smith; Jose Serate; Edward Pohlmann; Arthur D. Jones; Joshua J. Coon; Trey K. Sato; Gregg R. Sanford; Dustin Eilert; Lawrence G. Oates; Jeff S. Piotrowski; Donna M. Bates; David Cavalier; Yaoping Zhang

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2016

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