Engineering Commons^™

Fractionation And Characterization Of Lignin Streams From Genetically Engineered Switchgrass, Enshi Liu

Theses and Dissertations--Biosystems and Agricultural Engineering

Development of biomass feedstocks with desirable traits for cost-effective conversion is one of the main focus areas in biofuels research. As suggested by techno-economic analyses, the success of a lignocellulose-based biorefinery largely relies on the utilization of lignin to generate value-added products, i.e. fuels and chemicals. The fate of lignin and its structural/compositional changes during pretreatment have received increasing attention; however, the effect of genetic modification on the fractionation, depolymerization and catalytic upgrading of lignin from genetically engineered plants is not well understood. This study aims to fractionate and characterize the lignin streams from a wild-type and two genetically engineered …

Pretreatment, Enzymatic Hydrolysis, And Fermentation To Ethanol Using A Lignocellulosic Feedstock And Subsequent Recovery Of A Value Added Co-Product: Pure Crystalline Cellulose, Ryan J. Bouza

Electronic Theses and Dissertations

As more demand for alternatives to petroleum and the industrial world’s love of cars increase, cellulosic ethanol will become more important. The ethanol can, of course, be used in the transportation fuel sector, but there is also a potential for co-products to be developed out of the cellulose to ethanol process. Some of these co-products have the potential to replace current petrol products. These co-products may provide the extra revenue generation needed for further investment and development of this industry. This would not only provide better energy independence, but in the United States, it would better satisfy the cellulosic ethanol …

The Confounding Effects Of Particle Size And Substrate Bulk Density On Phanerochaete Chrysosporium Pretreatment On Panicum Virgatum, Amanda N. Hickman, Sue E. Nokes, William S. Sympson, Mathew J. Ruwaya, Michael D. Montross, Barbara L. Knutson

Biosystems and Agricultural Engineering Faculty Publications

Phanerochaete chrysosporium treatment is less effective as a biological pretreatment on feedstock with larger particle sizes. We hypothesized that the improved effectiveness of the pretreatment when smaller particle sizes are used may be due to the inherently higher bulk density with smaller particle sizes. The effects of substrate bulk density and particle size on the efficacy of P. chrysosporium pretreatment of switchgrass (Panicum virgatum) was tested experimentally. Phanerochaete chrysosporium was grown on senesced switchgrass (2 different particle sizes) with various bulk densities. In all treatments, the fungal-pretreated samples released more glucose during enzymatic saccharification than the control sample. …

Mapping The Membrane Proteome Of Anaerobic Gut Fungi Identifies A Wealth Of Carbohydrate Binding Proteins And Transporters, Susanna Seppälä, Kevin V. Solomon, Sean P. Gilmore, John K. Henske, Michelle A. O'Malley

School of Agricultural & Biological Engineering Faculty Publications

Background

Engineered cell factories that convert biomass into value-added compounds are emerging as a timely alternative to petroleum-based industries. Although often overlooked, integral membrane proteins such as solute transporters are pivotal for engineering efficient microbial chassis. Anaerobic gut fungi, adapted to degrade raw plant biomass in the intestines of herbivores, are a potential source of valuable transporters for biotechnology, yet very little is known about the membrane constituents of these non-conventional organisms. Here, we mined the transcriptome of three recently isolated strains of anaerobic fungi to identify membrane proteins responsible for sensing and transporting biomass hydrolysates within a competitive and …

Recirculating Calcium Hydroxide Solution: A Practical Choice For On-Farm High Solids Lignocellulose Pretreatment, William S. Sympson Jr.

Theses and Dissertations--Biosystems and Agricultural Engineering

Pretreatment is a necessary step in the utilization of lignocellulosic biomass for biochemical conversion to higher value products. There are multiple chemical choices for industrial settings, however on-farm choices are constrained to near ambient conditions with minimal specialized equipment, training, and limited waste disposal. Calcium hydroxide (lime) is suitable for on-farm use. This work presents the novel idea of pretreating biomass by recirculating a filtered, saturated lime solution in an up-flow, high solids (14-16% w/w) configuration at ambient conditions. In this system, lime solids were efficiently consumed, post-pretreatment washing of substrate did not significantly improve glucose yields, and energy and …

Switchgrass Storage Effects On The Recovery Of Carbohydrates After Liquid Hot Water Pretreatment And Enzymatic Hydrolysis, Noaa Frederick, Mengxing Li, Danielle Julie Carrier, Michael D. Buser, Mark R. Wilkins

Department of Biological Systems Engineering: Papers and Publications

Perennial grasses that would be used for bioenergy and bioproducts production will need to be stored for various periods of time to ensure a continual feedstock supply to a bioprocessing facility. The effects of storage practices on grass composition and the response of grasses to subsequent bioprocesses such as pretreatment and enzymatic hydrolysis needs to be understood to develop the most efficient storage protocols. This study examined the effect of outdoor storage of round switchgrass bales on composition before and after liquid hot water pretreatment (LHW) and enzymatic hydrolysis. This study also examined the effect of washing LHW pretreated biomass …

Characterization Of Genetically Modified High Biomass Producing Tobacco Plant, Pankaj Singh Kuhar

Department of Biological Systems Engineering: Dissertations and Theses

Global warming and peak oil has clouded our energy security. In light of this situation, bioethanol as emerged as one of the most amenable solutions to the problem. However bioethanol has its own shortcomings and transgenics seem imperative to exploit its full potential. A high biomass producing line in transgenic tobacco (Nicotiana tabacum cv. Xanthi) was identified during a routine genetic transformation, termed giant recombinant (GR). To characterize the phenotype of the giant line, growth rate and lignocellulosic composition was analyzed relative to the non-transgenic control line. The GR line accounted for 240% more biomass than the untransformed line …

Effects Of Sodium Hydroxide Pretreatment On Structural Components Of Biomass, Alicia A. Modenbach, Sue E. Nokes

Biosystems and Agricultural Engineering Faculty Publications

Pretreatment is a unit operation in the conversion of biomass to valuable products that utilizes various combinations of conditions, including chemicals, heat, pressure, and time, to reduce the recalcitrance of lignocellulose. Many such pretreatments have been developed over the years, as the operating conditions can be adapted so that lignocellulose is modified in ways unique to each pretreatment. By tailoring pretreatment conditions to achieve these modifications, the types of final products produced can be controlled. The purpose of this review is to provide a consolidated source of information for sodium hydroxide effects on lignocellulose. The structural characteristics of lignocellulose and …

Field Implementation Of Phanerochaete Chrysosporium Biomass Pretreatment: Fungal Identification And Inoculation Techniques, Bobby D. Carey Jr

Theses and Dissertations--Biosystems and Agricultural Engineering

Scaling biological pretreatment from the bench scale to the production scale may be more economical if unsterilized feedstock are used, however these allow for microbial competition from contaminates. An accurate and rapid method for identifying the desired biological pretreatment organism is necessary to confirm the presence of the desired organism when contaminates are morphologically similar to the target organism. Traditional methods, such as visual identification, sequencing, and selective plating can be time consuming and are sometimes still inconclusive. Based on methods described in the literature, plasmid DNA containing the marker genes gus (�-glucuronidase), LacZ, and gfp (green fluorescence protein) …