Biofuels Feedstock Development Research Articles

Transcriptomic and proteomic choreography in response to light quality variation reveals key adaption mechanisms in marine Nannochloropsis oceanica

Photosynthetic organisms need to respond frequently to the fluctuation of light quality and light quantity in their habitat. In response to the fluctuation of different single wavelength lights, these organisms have to adjust and optimize the employment of light energy by redistributing excitation energy and remodeling photosystem stoichiometry or light complex structure. However, the response of whole cellular processes to fluctuations in single wavelength light is mostly unknown. Here, we report the transcriptomic and proteomic dynamics and metabolic adaptation mechanisms of Nannochloropsis oceanica to blue and red light. Preferential exposure to different light spectra induces massive reprogramming of the Nannochloropsis transcriptome and proteome. Combined with physiological and biochemical investigation, the rewiring of many cellular processes was observed, including carbon/nitrogen assimilation, photosynthesis, chlorophyll and cartenoid biosynthesis, reactive oxygen species (ROS) scavenging systems, and chromatin state regulation. A strong and rapid regulation of genes or proteins related to nitrogen metabolism, photosynthesis, chlorophyll synthesis, ROS scavenging system, and carotenoid metabolism were observed during 12 h and 24 h of exposure under red light. Additionally, two light harvesting complex proteins induced by blue light and one by red light were observed. The differential responses of N. oceanica to red and blue irradiation reveal how marine microalgae adapt to change in light quality and can be exploited for biofuel feedstock development.

Carbon Emission Inventory of a Commercial-Scale Jatropha (Jatropha curcas L.) Biodiesel Processing Plant

Biofuel feedstock development is in limelight because of its pronounced capability to reduce greenhouse gas emissions (GHG). The move towards renewable energy intensified researches to provide concrete attestations that could be benefited from the effort. This research assessed the GHG reduction potential of biodiesel produced from Jatropha curcas L., relative to that of the conventional petroleum diesel. Computations were based on a standard 30-MLPY biodiesel plant with a co-generation facility, utilizing the byproducts of the process for electricity production. The GHG emissions were standardized and presented as equivalent carbon dioxide emission (CO2e). The boundary set for the analysis was from cradle to grave, considering the life-cycle from the production of the feedstock to the production of biodiesel, and eventually, its end-use. The Life Cycle Assessment (LCA) resulted to a negative net carbon footprint due to the carbon dioxide sequestration capability of the Jatropha plants. The whole system has a net CO2e footprint equivalent to 1,706,365.26 Mg CO2e a-1. Without considering the carbon dioxide absorbed by the plants, LCA of Jatropha biodiesel is still about 25% cleaner than petroleum diesel fuel. With sequestration, the GHG emission reduction can go as high as 548.38%. With the current Philippine biodiesel blending of 2%, if Jatropha methyl ester was used for the blending, this study shows that emission can be cut by 11%. And with increase in the blending, a more positive amount of savings will be achieved, which if at B100, savings could go as high as 581.18%.

Innovative technological paradigm-based approach towards biofuel feedstock

Biofuels produced from renewable energy biomass are playing a more significant role because of the environmental problems resulting from the use of fossil fuels. However, a major problem with biofuel production is that despite the range of feedstock that can be used, raw material availability varies considerably. By combining a series of theories and methods, the research objective of this study is to determine the current developments and the future trends in biofuel feedstock. By combining technological paradigm theory with literature mining, it was found that biofuel feedstock production development followed a three-stage trajectory, which was in accordance with the traditional technological paradigm – the S-curve. This new curve can be divided into BFDP (biofuel feedstock development paradigm) competition, BFDP diffusion, and BFDP shift. The biofuel production diffusion velocity model showed that there has been constant growth from 2000, with the growth rate reaching a peak in 2008, after which time it began to drop. Biofuel production worldwide is expected to remain unchanged until 2030 when a paradigm shift is expected. This study also illustrates the results of our innovative procedure – a combination of the data analysis system and the technological paradigm theory – for the present biofuel feedstock soft path that will lead to this paradigm shift, with integrated biofuel production feedstock systems expected to be a significant new trend.

Projecting future grassland productivity to assess the sustainability of potential biofuel feedstock areas in the Greater Platte River Basin

This study projects future (e.g., 2050 and 2099) grassland productivities in the Greater Platte River Basin (GPRB) using ecosystem performance (EP, a surrogate for measuring ecosystem productivity) models and future climate projections. The EP models developed from a previous study were based on the satellite vegetation index, site geophysical and biophysical features, and weather and climate drivers. The future climate data used in this study were derived from the National Center for Atmospheric Research Community Climate System Model 3.0 ‘SRES A1B’ (a ‘middle’ emissions path). The main objective of this study is to assess the future sustainability of the potential biofuel feedstock areas identified in a previous study. Results show that the potential biofuel feedstock areas (the more mesic eastern part of the GPRB) will remain productive (i.e., aboveground grassland biomass productivity >2750 kg ha � 1 year � 1 ) with a slight increasing trend in the future. The spatially averaged EPs for these areas are 3519, 3432, 3557, 3605, 3752, and 3583 kg ha � 1 year � 1 for current site potential (2000–2008 average), 2020, 2030, 2040, 2050, and 2099, respectively. Therefore, the identified potential biofuel feedstock areas will likely continue to be sustainable for future biofuel development. On the other hand, grasslands identified as having no biofuel potential in the drier western part of the GPRB would be expected to stay unproductive in the future (spatially averaged EPs are 1822, 1691, 1896, 2306, 1994, and 2169 kg ha � 1 year � 1 for site potential, 2020, 2030, 2040, 2050, and 2099). These areas should continue to be unsuitable for biofuel feedstock development in the future. These future grassland productivity estimation maps can help land managers to understand and adapt to the expected changes in future EP in the GPRB and to assess the future sustainability and feasibility of potential biofuel feedstock areas.

Evaluation of carbon fluxes and trends (2000–2008) in the Greater Platte River Basin: A sustainability study for potential biofuel feedstock development

This study evaluates the carbon fluxes and trends and examines the environmental sustainability (e.g., carbon budget, source or sink) of the potential biofuel feedstock sites identified in the Greater Platte River Basin (GPRB). A 9-year (2000–2008) time series of net ecosystem production (NEP), a measure of net carbon absorption or emission by ecosystems, was used to assess the historical trends and budgets of carbon flux for grasslands in the GPRB. The spatially averaged annual NEP (ANEP) for grassland areas that are possibly suitable for biofuel expansion (productive grasslands) was 71–169 g C m−2 year−1 during 2000–2008, indicating a carbon sink (more carbon is absorbed than released) in these areas. The spatially averaged ANEP for areas not suitable for biofuel feedstock development (less productive or degraded grasslands) was −47 to 69 g C m−2 year−1 during 2000–2008, showing a weak carbon source or a weak carbon sink (carbon emitted is nearly equal to carbon absorbed). The 9-year pre-harvest cumulative ANEP was 1166 g C m−2 for the suitable areas (a strong carbon sink) and 200 g C m−2 for the non-suitable areas (a weak carbon sink). Results demonstrate and confirm that our method of dynamic modeling of ecosystem performance can successfully identify areas desirable and sustainable for future biofuel feedstock development. This study provides useful information for land managers and decision makers to make optimal land use decisions regarding biofuel feedstock development and sustainability.

Development of a genome-wide multiple duplex-SSR protocol and its applications for the identification of selfed progeny in switchgrass

BackgroundSwitchgrass (Panicum virgatum) is a herbaceous crop for the cellulosic biofuel feedstock development in the USA and Europe. As switchgrass is a naturally outcrossing species, accurate identification of selfed progeny is important to producing inbreds, which can be used in the production of heterotic hybrids. Development of a technically reliable, time-saving and easily used marker system is needed to quantify and characterize breeding origin of progeny plants of targeted parents.ResultsGenome-wide screening of 915 mapped microsatellite (simple sequence repeat, SSR) markers was conducted, and 842 (92.0%) produced clear and scorable bands on a pooled DNA sample of eight switchgrass varieties. A total of 166 primer pairs were selected on the basis of their relatively even distribution in switchgrass genome and PCR amplification quality on 16 tetraploid genotypes. Mean polymorphic information content value for the 166 markers was 0.810 ranging from 0.116 to 0.959. From them, a core set of 48 loci, which had been mapped on 17 linkage groups, was further tested and optimized to develop 24 sets of duplex markers. Most of (up to 87.5%) targeted, but non-allelic amplicons within each duplex were separated by more than 10-bp. Using the established duplex PCR protocol, selfing ratio (i.e., selfed/all progeny x100%) was identified as 0% for a randomly selected open-pollinated ‘Kanlow’ genotype grown in the field, 15.4% for 22 field-grown plants of bagged inflorescences, and 77.3% for a selected plant grown in a growth chamber.ConclusionsThe study developed a duplex SSR-based PCR protocol consisting of 48 markers, providing ample choices of non-tightly-linked loci in switchgrass whole genome, and representing a powerful, time-saving and easily used method for the identification of selfed progeny in switchgrass. The protocol should be a valuable tool in switchgrass breeding efforts.

Switchgrass selection as a “model” bioenergy crop: A history of the process

A review of several publications of the Oak Ridge National Laboratory's Biofuels Feedstock Development Program and final reports from the herbaceous crop screening trials show that technology, environmental, and funding issues influenced the decision to focus on a single herbaceous “model” crop species. Screening trials funded by the U.S. Department of Energy in the late 1980s to early 1990s assessed thirty-four herbaceous species on a wide range of soil types at thirty-one different sites spread over seven states in crop producing regions of the U.S. Several species, including sorghums, reed canarygrass, wheatgrasses, and other crops, were identified as having merit for further development. Six of the seven institutions performing the screening included switchgrass among the species recommended for further development in their region and all recommended that perennial grasses be given high research priority. Reasons for the selection of switchgrass included demonstration of relatively high, reliable productivity across a wide geographical range, suitability for marginal quality land, low water and nutrient requirements, and other positive environmental attributes. Crop screening results, economic and environmental assessments by the Biofuels Feedstock Development Program staff, and Department of Energy funding limitations all contributed to the decision to further develop only switchgrass as a “model” or “prototype” species in 1991. The following ten year focus on development of switchgrass as a bioenergy crop proved the value of focusing on a single “model” herbaceous crop. The advancements and attention gained were sufficient to give government leaders, policymakers, farmers, and biofuel industry developers the confidence that lignocellulosic crops could support an economically viable and environmentally sustainable biofuel industry in the U.S.

Short-rotation woody crop supply systems in the United States: what do we know and what do we need to know?

Short-rotation woody crop (SRWC) supply systems have been proposed over the past 20 years as a means of rapidly producing biomass for fiber and fuels. The U.S. Department of Energy, through the Biofuels Feedstock Development Program and its partners, has selected model species, developed silvicultural systems and created genetically improved clonal planting stock for use in SRWC supply systems. Spacing, fertilizer and pesticide prescriptions have been developed for several species and regions within the U.S. Breeding and genetic improvement projects continue to identify and select plant materials which display increased productivity and pest resistance. Genetic transformation, somaclonal variation and marker-assisted selection are being used to supplement traditional breeding work. Harvesting and handling methods are currently relying on traditional combinations of existing equipment. Nevertheless, technical and environmental issues related to: (1) long-term use of fertilizers and irrigation; (2) deployment of clonal planting stock; and (3) development of customized harvesting equipment remain as unresolved issues related to further deployment and commercialization of SRWC systems. Overall determination of SRWC sustainability will require resolution of these issues.

Production function for short-rotation woody-crop Populus spp. plantations

Short-rotation woody-crop Populus spp. plantations have the potential to produce large amounts of biomass in short time periods, typically 4–8 years. A production function equation is shown to predict yields for such plantations. The equation is based, in part, on information from biomass production experiments conducted across the United States. These experimental plots are sponsored by the Biofuels Feedstock Development Program of Oak Ridge National Laboratory. The equation uses nine parameters including both cultural practices and climatic and soil site conditions as independent variables. The equation (R2 = 0.86) is accurate and applicable to a wide range of conditions.

Biomass energy production in the United States: an overview

This paper summarizes reports prepared for the U.S. Environmental Protection Agency (EPA) by researchers at the U.S. Department of Energy's (DOE) Oak Ridge National Laboratory (ORNL). It also presents conclusions from a Biomass Energy Strategies Workshop conducted at ORNL. The Biofuels Feedstock Development Program (BFDP) has largely concentrated on the development of dedicated biomass feedstocks, referred to as energy crops. Two general types of energy crops have received the most attention—short-rotation woody crops (SRWC) and herbaceous energy crops (HEC). These cropping systems use traditional food production technologies as a means of maximizing the production of biomass per unit of land. Research focuses on the development of new crops and cropping technologies. The reports prepared for EPA and summarized by this article include discussions of crop production technologies, available land, economic considerations and environmental trade-offs. The discussion of other sources of biomass occurs only in the context of the workshop on biomass energy strategies. [The views expressed in this paper are those of the authors and do not necessarily represent the views of the U.S. Environmental Protection Agency or the U.S. Department of Energy.]