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

Bioenergy cropping systems that incorporate native grasses stimulate growth of plant-associated soil microbes in the absence of nitrogen fertilization

Lawrence G. Oates; David S. Duncan; Gregg R. Sanford; Chao Liang; Randall D. Jackson

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2016

The choice of crops and their management can strongly influence soil microbial communities and their processes. We used lipid biomarker profiling to characterize how soil microbial composition of five potential bioenergy cropping systems diverged from a common baseline five years after they were established. The cropping systems we studied included an annual system (continuous no-till corn) and four perennial crops (switchgrass, miscanthus, hybrid poplar, and restored prairie). Partial- and no-stover removal were compared for the corn system, while N-additions were compared to unfertilized plots for the perennial cropping systems. Arbuscular mycorrhizal fungi (AMF) and Gram-negative biomass was higher in unfertilized perennial grass systems, especially in switchgrass and prairie. Gram-positive bacterial biomass decreased in all systems relative to baseline values in surface soils (0–10 cm), but not subsurface soils (10–25 cm). Overall microbial composition was similar between the two soil depths. Our findings demonstrate the capacity of unfertilized perennial cropping systems to recreate microbial composition found in undisturbed soil environments and indicate how strongly agroecosystem management decisions such as N addition and plant community composition can influence soil microbial assemblages.

Cellulose-enriched microbial communities from leaf-cutter ant (Atta colombica) refuse dumps vary in taxonomic composition and degradation ability

Gina R. Lewin; Amanda L. Johnson; Rolando D. Soto; Kailene Perry; Adam J. Book; Heidi A. Horn; Adrian A. Pinto-Tomas; Cameron R. Currie

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2016

Deconstruction of the cellulose in plant cell walls is critical for carbon flow through ecosystems and for the production of sustainable cellulosic biofuels. Our understanding of cellulose deconstruction is largely limited to the study of microbes in isolation, but in nature, this process is driven by microbes within complex communities. In Neotropical forests, microbes in leaf-cutter ant refuse dumps are important for carbon turnover. These dumps consist of decaying plant material and a diverse bacterial community, as shown here by electron microscopy. To study the portion of the community capable of cellulose degradation, we performed enrichments on cellulose using material from five Atta colombica refuse dumps. The ability of enriched communities to degrade cellulose varied significantly across refuse dumps. 16S rRNA gene amplicon sequencing of enriched samples identified that the community structure correlated with refuse dump and with degradation ability. Overall, samples were dominated by Bacteroidetes, Gammaproteobacteria, and Betaproteobacteria. Half of abundant operational taxonomic units (OTUs) across samples were classified within genera containing known cellulose degraders, including Acidovorax, the most abundant OTU detected across samples, which was positively correlated with cellulolytic ability. A representative Acidovorax strain was isolated, but did not grow on cellulose alone. Phenotypic and compositional analyses of enrichment cultures, such as those presented here, help link community composition with cellulolytic ability and provide insight into the complexity of community-based cellulose degradation.

Climate-smart soils

Keith Paustian; Johannes Lehmann; Stephen Ogle; David Reay; Philip Robertson; Pete Smith

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2016

Soils are integral to the function of all terrestrial ecosystems and to food and fibre production. An overlooked aspect of soils is their potential to mitigate greenhouse gas emissions. Although proven practices exist, the implementation of soil-based greenhouse gas mitigation activities are at an early stage and accurately quantifying emissions and reductions remains a substantial challenge. Emerging research and information technology developments provide the potential for a broader inclusion of soils in greenhouse gas policies. Here we highlight ‘state of the art’ soil greenhouse gas research, summarize mitigation practices and potentials, identify gaps in data and understanding and suggest ways to close such gaps through new research, technology and collaboration.

Comparative genomics provides new insights into the diversity, physiology, and sexuality of the only industrially exploited tremellomycete: Phaffia rhodozyma

Nicolas Bellora; Martin Moline; Marcia David-Palma; Marco A. Coelho; Chris T. Hittinger; Jose P. Sampaio; Paula Goncalves; Diego Libkind

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2016

BACKGROUND: The class Tremellomycete (Agaricomycotina) encompasses more than 380 fungi. Although there are a few edible Tremella spp., the only species with current biotechnological use is the astaxanthin-producing yeast Phaffia rhodozyma (Cystofilobasidiales). Besides astaxanthin, a carotenoid pigment with potent antioxidant activity and great value for aquaculture and pharmaceutical industries, P. rhodozyma possesses multiple exceptional traits of fundamental and applied interest. The aim of this study was to obtain, and analyze two new genome sequences of representative strains from the northern (CBS 7918T, the type strain) and southern hemispheres (CRUB 1149) and compre them to a previously published genome sequence (strain CBS 6938). Photoprotection and antioxidant related genes, as well as genes involved in sexual reproduction were analyzed. RESULTS: Both genomes had ca. 19 Mb and 6000 protein coding genes, similar to CBS 6938. Compared to other fungal genomes P. rhodozyma strains and other Cystofilobasidiales have the highest number of intron-containing genes and highest number of introns per gene. The Patagonian strain showed 4.4 % of nucleotide sequence divergence compared to the European strains which differed from each other by only 0.073 %. All known genes related to the synthesis of astaxanthin were annotated. A hitherto unknown gene cluster potentially responsible for photoprotection (mycosporines) was found in the newly sequenced P. rhodozyma strains but was absent in the non-mycosporinogenic strain CBS 6938. A broad battery of enzymes that act as scavengers of free radical oxygen species were detected, including catalases and superoxide dismutases (SODs). Additionally, genes involved in sexual reproduction were found and annotated. CONCLUSIONS: A draft genome sequence of the type strain of P. rhodozyma is now available, and comparison with that of the Patagonian population suggests the latter deserves to be assigned to a distinct variety. An unexpected genetic trait regarding high occurrence of introns in P. rhodozyma and other Cystofilobasidiales was revealed. New genomic insights into fungal homothallism were also provided. The genetic basis of several additional photoprotective and antioxidant strategies were described, indicating that P. rhodozyma is one of the fungi most well-equipped to cope with environmental oxidative stress, a factor that has probably contributed to shaping its genome.

Comparative productivity of alternative cellulosic bioenergy cropping systems in the North Central USA

Gregg R. Sanford; Lawrence G. Oates; Poonam Jasrotia; Kurt D. Thelen; Philip Robertson; Randall D. Jackson

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2016

Biofuels from lignocellulosic feedstocks have the potential to improve a wide range of ecosystem services while simultaneously reducing dependence on fossil fuels. Here, we report on the six-year production potential (above ground net primary production, ANPP), post-frost harvested biomass (yield), and gross harvest efficiency (GHE = yield/ANPP) of seven model bioenergy cropping systems in both southcentral Wisconsin (ARL) and southwest Michigan (KBS). The cropping systems studied were continuous corn (Zea mays L.), switchgrass (Panicum virgatum L.), giant miscanthus (Miscanthus × giganteus Greef & Deuter ex Hodkinson & Renvoize), hybrid poplar (Populus nigra × P. maximowiczii A. Henry ‘NM6’), a native grass mixture (5 sown species), an early successional community, and a restored prairie (18 sown species). Overall the most productive cropping systems were corn > giant miscanthus > and switchgrass, which were significantly more productive than native grasses ≈ restored prairie ≈ early successional ≈ and hybrid poplar, although some systems (e.g. hybrid poplar) differed significantly by location. Highest total ANPP was observed in giant miscanthus (35.2 ± 2.0 Mg ha−1 yr−1) at KBS during the sixth growing season. Six-year cumulative biomass yield from hybrid poplar at KBS (55.4 ± 1.3 Mg ha−1) was high but significantly lower than corn and giant miscanthus (65.5 ± 1.5, 65.2 ± 5.5 Mg ha−1, respectively). Hypothesized yield advantages of diversity in perennial cropping systems were not observed during this period. Harvested biomass yields were 60, 56, and 44% of ANPP for corn, perennial grass, and restored prairie, respectively, suggesting that relatively simple changes in agronomic management (e.g. harvest timing and harvest equipment modification) may provide significant gains in bioenergy crop yields. Species composition was an important determinant of GHE in more diverse systems. Results show that well-established, dedicated bioenergy crops are capable of producing as much biomass as corn stover, but with fewer inputs.

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