2015 Project List

The remarkable role of lignin in enhancing enzymatic hydrolysis of lignocellulosic biomass (Dr. Maobing Tu)

The interactions between lignin and cellulases play an important role in the effective enzymatic hydrolysis of lignocellulosic biomass. Lignin removal has been closely associated with pretreatment efficiency and substrate hydrolysability. However, remarkably we have found that certain type of lignin can increase the enzymatic hydrolysis of Avicel and pretreated biomass. In this study, we will quantitate the effects of softwood and hardwood organosolv lignin (EOL) on enzymatic hydrolysis of Avicel based on the initial hydrolysis rate and the 72-h hydrolysis yield. Organosolv lignin will be collected from ethanol organosolv pretreatment of Cottonwood, Willow, Aspen, Eucalyptus and Loblolly pine. These hardwood and softwood lignin will be added into enzymatic hydrolysis of Avicel and the 72-h hydrolysis yield will be determined. The initial hydrolysis rate will be also determined with the addition of organosolv lignin. Furthermore, we will examine the functional groups and structural features of organosolv lignin by 1H and 13C NMR. Our study will elucidate the distinct role of lignin in enzymatic hydrolysis of lignocellulsoic biomass. This research has great potential to improve the effectiveness of enzymatic hydrolysis. 

Thermosetting polymer resins from algal triglycerides (Dr. Maria Auad)

Thermosetting polymer resins (i.e. epoxy, unsaturated polyesters and polyurethanes) play an important role in industry due to their high versatility with respect to physical, thermal and mechanical properties, leading to materials with high modulus, strength, durability and chemical resistance to solvents, provided by the high crosslink density. Recently, there has been an increased interest on the partial or total replacement of petroleum-based resources for bio-based compounds for the production of polymeric resins. Uncertainty in terms of availability of petroleum and the global tendencies toward sustainable development has been urging the chemical industry toward a sustainable chemistry and particularly the use of renewable resources, such as algae, for the production of bio-based systems. These new materials can compete or surpass the performance of the existing materials with the addition of low cost, eco–friendly characteristics and outstanding properties. In particular, algae are fast growing organisms. They are mainly composted up to 60% by weight of different oils (triglycerides) that can be chemically modified to produce different type of chemical functionalities. During the development of this REU work, Dr. Auad and the student proposes to use renewable algal triglycerides to produce polymeric bio-resins coatings of fast cure with high water, cracking and peeling resistance. In addition, these coatings can provide an effective adhesive effect to typical polar substrates (wood, polyamide 6, glass, etc.) compared with synthetic resins due to free pending organic groups (hydroxyl and carboxylic groups) of the structure.

Production of gasoline from alcohols in a micro-channel reactor (Dr. Sushil Adhikari)
Synthesis gas derived from biomass gasification can be used to produce alcohols or hydrocarbons. However, there is a limitation on how much alcohols can be blended with conventional transportation fuels without adversely impacting engines. Process like Fisher-Tropsch synthesis (FTS) can be used to produce syngas to hydrocarbons but the FTS produces wide range of products and selectivity towards a particular type of fuel is low.  Synthesis gas to methanol is highly selective and Mobil oil was the first to discover and develop zeolite based methanol to gasoline technology using zeolite ZSM-5 catalyst. In this project, the REU fellow will study the effect of temperature, pressure, and catalyst type on gasoline production from methanol and ethanol. In addition, the fellow will compare the performance of methanol to gasoline process between fixed-bed and microchannel reactors.

Film, coating and fibers from algal proteins (Dr. Maria Auad)

All algae are primary comprise of proteins, carbohydrates, oils (triglycerides) and nucleic acids in varying proportions. Several analyses of gross chemical composition of different algae have been published in the literature. In particular algal proteins are of specific interest for this work. Proteins are large biological molecules, or macromolecules, consisting of one or more long chains of amino acid which possess common structural features, including α-carbon to which an amino group (NH2), a carboxyl group (COOH), and a side chain. Due to the complexity in their composition and structure, proteins possess multiple function properties such as solubility, gelation, elasticity, emulsification, and cohesion-adhesion. Therefore, traditionally proteins such as soy bean protein and gelatin are used in the adhesive industry and as comestible films. These protein films have showed excellent barrier properties and lower water permeability. During the course of this REU proposal, Dr. Auad and the REU student will develop biodegradable polymeric films coatings and fibers from algal proteins to be used in the packaging or coating industry. 

Production of carbon nano-composites using microwave for energy storage (Dr. Xinyu Zhang)

With development in renewable energy sources and intermittent power generation, a need for high density energy and power storage materials has emerged.  Most advanced batteries rely upon rare inorganic materials for ion exchange.  Renewable materials alone are not good conductors but can be coated with carbon nano-composites (CNCs) to be used as effective electrodes.  Current standards use chemical decomposition to carbonize polymers into CNCs; however, microwave decomposition may serve as a more energy and time effective method to convert conducting polymers to CNCs.  Renewable electrodes have the potential to reduce the production costs of electrodes and produce synergistic energy and power storage effects when successfully composited with conducting polymers. During the course of this REU proposal, the REU student will develop carbon nano-composites using microwave and characterize those materials for the efficacy of energy storage.

 Enhancing Acetone-butanol-ethanol (ABE) production by overexpressing heat shock protein genes in Clostridium beijerinckii(Dr. Yi Wang)

Biobutanol has been of great interest because of its various advantages as a biofuel and considerable value as an industrial chemical feedstock. Biobutanol is usually produced by solventogenic clostridia through a fermentation process that can produce acetone, butanol, and ethanol (and thus the process is also termed as ABE fermentation) among which butanol accounts for the largest fraction. C. beijerinckii is one of the most prominent solvent-producing species. However, the butanol production by this microorganism is still unsatisfying due to the poor tolerance of the cells to the end product (particularly butanol) resulting in low butanol titer and productivity. Heat shock protein play an essential role in the synthesis, transport, and folding of proteins. Under heat shock or other stress conditions, they primarily serve to prevent aggregation and assist in protein folding. It has been reported that the solvent stress is linked to the heat shock stress. Toxic solvents have been shown to induce known heat shock proteins. It has also been reported that the overexpression of heat shock genes in some solventogenic clostridia can enhance the butanol tolerance in the host strains and thus improve the solvent production. Therefore, the objective of this study is to overexpress the heat shock protein genes in C. beijerinckii in order to enhance the solvent production from renewable carbonsources using the engineered strain.  The REU fellow student will work with the graduate students to construct the mutant strain and perform fermentation experiments under various conditions to characterize the engineered strain. During this process, the REU student will gain a good training in genetic engineering basics, fermentation operations, and product analysis.

Behavior of bark from short rotation woody crops (Dr. Oladiran Fasina)

Short rotation woody crops (e.g. fast growing species such as Eucalyptus, poplar) have been identified as being part of the bioenergy solution to reducing the nations’ dependence on crude oil. Preliminary investigation conducted in the laboratory shows that the bark of short-rotation Eucalyptus behaves differently than those from typical softwood with slower growth rate. These handling characteristics seem to have the potential of impeding the ability to pre-process short-rotation woody crops before entering the throat of conversion plants. The student fellow will use techniques such as nuclear magnetic resonance (NMR), SEM (scanning electron microscopy), TGA (thermogravimetric analysis) and infrared spectroscopy (FTIR and FTNIR) to characterize the effect of age on morphology, structure, state of moisture and thermal decomposition behavior of the bark of short rotation woody crops. The results will be compared to that of loblolly pine wood bark – the predominant wood specie in the southern US.

Lightweight construction wood composites using a combination of biobased fibers, soy, and conductive binders (Dr. Brian Via)

Oriented Strand Board (OSB) is the most common wood composite used in residential construction and is bonded with phenol formaldehyde (PF) adhesives.  But PF costs $2.00 per lb (at 100% solids content) and is nearly completely derived from petroleum based processes.  It has been shown that soy can be used to partially replace phenol formaldehyde and only costs $0.30 to $1.00 per lb depending on the grade used.  Replacement of PF with soy results in a more environmentally friendly adhesive that uses less petroleum and partially mitigates the emission of dangerous formaldehydes. Nano or microfibrilliated cellulose fibers can be added to the soy/adhesive mixture to prevent fracture at the bondline resulting in improved adhesive performance. Lighter weight OSB panels are also desirable because delivery trucks use less gasoline during transport.  But a light weight panel has more air voids between wood particles and this has the disadvantage of requiring longer press times during manufacturing resulting in increased energy usage.  This portion of the project will pursue the addition of carbon nanotubes (CNT) which we anticipate will reduce press time (at 420 ºF) by ½ minute when 0.5% by weight CNT loading is used. Given this project is just for a summer period, only a portion of this project can be worked on.  Dr. Via will therefore work with the student to choose which portion is of most interest.

Aligned cellulose nanocrystal coatings (Dr. Virginia A. Davis)

Dr. Virginia Davis’ group is focused on the assembly of nanoscale building blocks into bulk materials.  Cellulose nanocrystals (CNC) produced by the acid hydrolysis of natural cellulosic materials are increasingly being recognized for their potential in advanced materials applications. They have similar surface chemistry to silicon and high mechanical strength.  The research group is looking at how the optical and mechanical properties of CNC films can be controlled by changing the concentration, shear rate thickness and drying method. The REU student will contribute to this research by making dispersions and films and characterizing them for their optical and mechanical properties. The ultimate goal is to develop CNC films for both more energy efficient displays and MEMS applications. 

Elucidating xylose fermentation through metabolic network modeling (Dr. Jin Wang)

Lignocellulosic ethanol has been identified as one of the most promising long-term renewable energy sources, not only because lignocellulosic biomass is the most abundant and inexpensive renewable feedstock for ethanol production, but also because cellulosic ethanol can reduce both energy input and greenhouse gas emissions by more than 85% compared to fossil fuels and corn ethanol. Although ethanol fermentation of glucose derived from cellulosic biomass, using Saccharomyces cerevisiae, is well established on a large scale, the conversion of the xylose, one major sugar component of hemicelluloses, to ethanol is still one of the major barriers of industrializing lignocellulosic ethanol processes. Scheffersomyces stipitis has been shown to be the most promising wild strain for direct high-yield fermentation of xylose without byproduct formation, and it has been a source of genes for engineering xylose metabolism in S. cerevisiae. Dr. Wang’s group has constructed a central carbon metabolic network model as well as a revised genome scale metabolic network model for S. stipitis. In this project, the REU fellow will work with a graduate student to conduct designed experiments to validate the model as well as improve them based on experimental results.

Understanding the type of volatile compounds from bio-oil during storage (Dr. Sushil Adhikari)

The conversion of biomass to pyrolysis oil (bio-oil) and subsequent conversion to gasoline and diesel range compounds have significant potential for reducing the United States’ dependence on current petroleum imports. However, this oil is unstable and acidic, contains char particles, and has about half the heating value of petroleum liquid fuels. These properties of bio-oil have restricted its use in commercial applications. In addition, these bio-oils have burning smell and pro-longed exposure might cause eye-irritation and other health issues. It is imperative to understand the types of volatile compounds generated during storage. The REU fellow will analyze headspace samples using highly sophisticated instrument. The fellow will elucidate the effect of storage temperate and biomass types on volatiles production. 

Last Updated: Dec 01, 2014