College of Agriculture & Natural Resources

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The collections in this community comprise faculty research works, as well as graduate theses and dissertations.

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Subject: search.filters.subject.Biomass

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    Directed plant cell-wall accumulation of iron: embedding co-catalyst for efficient biomass conversion
    (Springer Nature, 2016-10-21) Lin, Chien-Yuan; Jakes, Joseph E.; Donohoe, Bryon S.; Ciesielski, Peter N.; Yang, Haibing; Gleber, Sophie-Charlotte; Vogt, Stefan; Ding, Shi-You; Peer, Wendy A.; Murphy, Angus S.; McCann, Maureen C.; Himmel, Michael E.; Tucker, Melvin P.; Wei, Hui
    Plant lignocellulosic biomass is an abundant, renewable feedstock for the production of biobased fuels and chemicals. Previously, we showed that iron can act as a co-catalyst to improve the deconstruction of lignocellulosic biomass. However, directly adding iron catalysts into biomass prior to pretreatment is diffusion limited, and increases the cost of biorefinery operations. Recently, we developed a new strategy for expressing iron-storage protein ferritin intracellularly to accumulate iron as a catalyst for the downstream deconstruction of lignocellulosic biomass. In this study, we extend this approach by fusing the heterologous ferritin gene with a signal peptide for secretion into Arabidopsis cell walls (referred to here as FerEX). The transgenic Arabidopsis plants. FerEX. accumulated iron under both normal and iron-fertilized growth conditions; under the latter (iron-fertilized) condition, FerEX transgenic plants showed an increase in plant height and dry weight by 12 and 18 %, respectively, compared with the empty vector control plants. The SDS- and native-PAGE separation of cell-wall protein extracts followed by Western blot analyses confirmed the extracellular expression of ferritin in FerEX plants. Meanwhile, Perls' Prussian blue staining and X-ray fluorescence microscopy (XFM) maps revealed iron depositions in both the secondary and compound middle lamellae cell-wall layers, as well as in some of the corner compound middle lamella in FerEX. Remarkably, their harvested biomasses showed enhanced pretreatability and digestibility, releasing, respectively, 21 % more glucose and 34 % more xylose than the empty vector control plants. These values are significantly higher than those of our recently obtained ferritin intracellularly expressed plants. This study demonstrated that extracellular expression of ferritin in Arabidopsis can produce plants with increased growth and iron accumulation, and reduced thermal and enzymatic recalcitrance. The results are attributed to the intimate colocation of the iron co-catalyst and the cellulose and hemicellulose within the plant cell-wall region, supporting the genetic modification strategy for incorporating conversion catalysts into energy crops prior to harvesting or processing at the biorefinery.
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    CHARACTERIZATION OF ALGAL BIOMEAL FOR APPLICATIONS IN FOOD
    (2009) Sanghvi, Avani Mukesh; Lo, Martin; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Conventionally used as animal feeds, microalgae are now cultivated for products such as omega-3 fatty acids, resulting in a high amount of biomass as by-product. The biomass obtained after the extraction of DHA from Crypthecodinium cohnii is called `algal biomeal'. Being nutritionally rich, the biomeal has potential to be used as a value-added ingredient in human food and animal feeds. Evaluation of the biomeal properties resulted in the development of a water-based sauce formulation which was analyzed for its proximate composition, textural attributes and microbial stability. The sauce was rich in carbohydrate and protein with low fat and ash content. It was microbiologically and texturally stable under refrigeration. This research shows that development of a shelf-stable palatability enhancer using algal biomeal offers a new ingredient for the food and feed industries, whereas the ability to produce a value-added ingredient also offers a viable option for algal biomeal.
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    Integrated Energy, Environmental and Financial Analysis of Biofuel Production from Switchgrass, Hybrid Poplar, Soybean and Castorbean
    (2007-01-22) Felix, Erika Ruth; Tilley, David R; Biological Resources Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Biofuels are considered a substitute for petroleum-fuels, but to be viable they should not depend heavily upon non-renewable resources. The objective of this study was to estimate the ultimate amount of energy required to produce liquid-fuels from switchgrass, hybrid poplar, soybean, and castorbean. Emergy (with an "m") accounting was used to integrate all environmental, fossil fuel, and human-service inputs used throughout the production chain from agricultural field to processing facility. Depending on feedstock type and conversion yields, environmental inputs were between 21-44%, fossil fuels were 18-73% and human-derived services were 2-61%. Gallons of transportation fuel produced per gallon of petroleum used ranged from 0.06 to 4.2 for ethanol and 2.6 to 4.4 for biodiesel. No biofuel was made with less than 75% non-renewable resources. Energy embodied in "hidden" indirect paths ranged from 38-99%. The viability of replacing petroleum with cellulosic ethanol or biodiesel is highly questionable.