Projects in Bio-Based Products
This page describes the projects that illustrate the type of work we perform in bio-based product research and development. We are seeking interested and capable partners in commercialization of these new product concepts. For a historical perspective of our progress in this field, our completed projects are described separately.
Value-Added Products from Hemicellulose Utilization in Dry-Mill Ethanol Plants
This project is funded by the Department of Agriculture and the Department of Energy (DOE), jointly. The participants in the project include two of DOE's national laboratories, PNNL and the Idaho National Engineering and Environmental Laboratory, and a commercial partner, Kemin Industries. The project is cosponsored and managed by the Iowa Corn Promotion Board with the Minnesota and Ohio Corn Growers Associations. The specific objective of this project is to create value-added products from ethanol dry-mill facilities. The feedstock is the corn hemicellulose from the dry-mill ethanol process, currently used as a very low-value animal feed. The project will integrate highly efficient fermentations with high-yielding aqueous-phase catalysis to create substantial value. The value created at the smaller dry-mill facilities will help the overall economics of ethanol fermentation substantially. This in turn will facilitate the expansion of the ethanol industry and help the industry move toward the DOE goal of 5 billion gallons of ethanol by 2020.
In established commercial bioprocess research laboratories, iterative experiments at the shake flask, small fermentor and process prototype fermentor levels are employed to establish and validate a new process. One of the significant bottlenecks in bioprocess research is the requirement for large numbers of repetitive experiments using batch fermentation technology. Usually only one variable can be examined in each experiment and large numbers of shake flask experiments are often performed in parallel with the batch fermentor experiments. In this standard approach to deployment of new bioprocesses, the time limiting factor is labor and availability of equipment. An alternative to this standard approach is to use continuous culture technology, often referred to as chemostat or auxostat technology. In this project another tool, Chemostat Technology is being developed to support state-of-the-art fungal research.
There are three important attributes of this technology.
- It offers a more efficient approach to bioprocess research that means a shorter timeline from idea to prototype process.
- It complements and extends the usefulness of proteomics as it applies to fundamental research and bioprocess research.
- Engineered mutants can be evaluated quickly and continuous selection experiments can replace the laborious mutagenesis and screening approach to bioprocess improvement.
For rapid development of novel processes and determination of optimum operating conditions, performing optimization investigations using continuous culture (chemostat technology) will reduce new product/process development time. For example, growth rate and product formation can be measured on several carbon sources or at several pH levels in a single continuous culture experiment. The optimal medium composition can be determined in an experiment to optimize major (carbon source, nitrogen source) and minor (salts, micronutrients) medium components.
Proteomics research will be greatly improved using chemostat technology. An underlying premise in proteomics research is that variations in batch-to-batch samples are negligible with respect to the protein fractions from fungal cells. This uncertainty associated with the premise can be reduced via the chemostat. A fungus grown in a chemostat can be examined under conditions of balanced growth. Having achieved a steady state, critical factors hypothesized to affect the proteome can be assessed by sampling the steady state, change the parameter and sampling again.
Filamentous fungi are used in manufacturing processes to make acids, enzymes and pharmaceutical products. For filamentous fungi a particular morphology is often associated with maximum product output. It is logical to hypothesize that genes control this morphology and that these genes will be useful to drive improved production of desirable products in taxonomically diverse filamentous fungi. It is the intent of this project to identify and clone the critical morphology control genes and use them to improve the output of commercially important organic acids by fungi identified in an associated project, Fungal Discovery. The objective of this project is to identify genes that control the morphology of filamentous fungi, and genetically modify model organisms so that this morphology change can be controlled at will in fungal fermentations. Details: Fungal Genetics (.pdf, 1.4Mb)
The project employs the unique proteomics capabilities at PNNL to identify proteins critical to morphological development in Phanerochaete. chrysosporium. White rot fungi, including Phanerochaete, are the only microorganisms that degrade significant amounts of lignin; a complex and highly cross-linked material involved in maintaining structural rigidity in plants. As a result of studies designed to maximize ligninase production, there is a body of bioprocess literature on the culture of this organism in stirred-tank reactors. The characteristic filamentous growth agglomerates and attaches to various parts of the vessel, including operationally important process monitoring and control equipment. This results in low yields of the desired enzymes. To control the morphology investigators have employed various immobilization techniques such as alginate beads, urethane beads or stainless steel mesh with little success. Research at PNNL on Phanerochaete has led to an observation on the positive effect of high concentrations of glucose on morphology. The morphology of the organism at high glucose and low glucose concentrations is quite different, leading to the hypothesis that different genes are expressed. Using proteomics the genes are being identified and studied to determine the nature of the genetic control of morphology in this fungus.
The objective of this project is to develop an economic process for the separation of corn fiber into its core building blocks. The general component groups in the corn fiber stream derived from corn processing facilities include starch, cellulose, hemicellulose, polyphenolics, oil, and ash. This project is developing a technology platform to separate these component groups and convert them into the core building blocks; glucose, arabinose, xylose, ferulic acid, and the specific components of the oil fraction (.pdf, 196Kb): triglycerides, and sterols. The most abundant core building blocks, glucose, xylose and arabinose are being evaluated as a feedstock for either fermentation to ethanol or direct aqueous phase catalytic conversion to proylene glycol, ethylene glycol, and glycerol. The ferulic acid will be evaluated as a feedstock for the production of vanillin. The specific components from the oil fraction will be sold into existing markets and contributes significantly to the overall economic viability of the project. This is a CRADA project with the National Corn Growers Association and Archer Daniels Midland. This project is now in the pilot-scale testing phase which will be completed near the end of calendar year 2005.
Our project focuses on developing new catalytic materials and novel processes for the conversion of sorbitol to isosorbide. Isosorbide (1,4-3,6-dianhydrosorbitol) is derived from the acid catalyzed cyclic dehydration of sorbitol, which in turn is derived from glucose via hydrogenation. Recent patents have shown that isosorbide drastically improves properties of materials like polyethyleneterephthalate (PET) when used as a copolymer. This new potential market for isosorbide affords a substantial opportunity to develop a cost-competitive process that utilizes renewable feedstocks. The object of this project is two-fold: (1) develop an improved process that increases the yield to isosorbide and (2) create a more environmentally benign process. Sorbitol dehydration is an acid catalyzed process that is done commercially on a relatively small scale with mineral acid catalysis. Such catalysts create separation and waste disposal issues. An improved, economically viable process would employ heterogeneous solid acids supporting either batch or continuous processes.
Process development is underway for a hydrothermal gasification technology for recovery of energy from wet biomass including unconverted residuals from ethanol fermentation. Research includes preliminary batch reactor testing with the wet biomass materials, bench-scale continuous-flow process testing to develop process kinetics and address various handling issues, and testing in a 10 gallon/hr processing unit to scale-up the process, thus verifying the reactivity of these feedstocks and the processability of their slurries in this high-pressure process. The preliminary economic assessment provided a basis for evaluation of application of the technology to various biomass residual feedstocks. Catalyst contamination and poisoning was identified as a remaining technology hurdle. This process development effort is the latest stage of work on a processing concept initially investigated as a fuels-from-biomass technology in the 1980s.
The work builds on the extensive effort at PNNL in catalyst development for high-pressure aqueous phase gasification that was undertaken during the past decade. The process provides an efficient means to recover the energy left in residual material from ethanol production, particularly from lignocellulosic feedstocks. This process not only improves the overall process efficiency of ethanol production, but it addresses the requirement for wastewater treatment inherent in the fermentation. In addition, the technology has potential for use in energy recovery from other wet biomass processing residues from sugar production processes and biorefinery concepts. Details: Chemical Processing in High-Pressure Aqueous Environments. 7. Process Development for Catalytic Gasification of Wet Biomass Feedstocks (.pdf, 599Kb)
A CRADA project is now underway with Antares Group and Eastman Chemical to develop a workable process for application to biosludge. Development of process steps to allow treatment of wet biomass, including mineral matter and sulfur, by catalytic hydrothermal gasification with long-term protection of the catalyst is the key deliverable for this project.
For this bio-oil (fast pyrolysis of biomass) upgrading process development, research will be conducted in existing bench-scale batch reactor systems at PNNL to evaluate new catalysts and a bench-scale continuous flow reactor operated with bio-oil feedstocks and feedstock fractions to determine kinetic parameters for the conversion and catalyst deactivation and lifetime data. The process test results will be used to provide a new basis for process economics.
Previous studies in this area have focused on the use of petroleum refining technology for analogous processing steps for bio-oil. The progress in this field advanced to the level of laboratory demonstration of such processing systems with useful catalysts and processing parameters identified. However, recent developments in catalyst formulation, specifically developed for use with biomass-derived materials in the presence of large amounts of water, are now expected to provide improvements to the overall processing efficiency through reduced hydrogen requirements and reduced processing severity with improved catalyst longevity.
A CRADA project is now underway with UOP LLC to develop bio-oil processing technology which will allow bio-oil to be used as supplemental feedstock to existing petroleum refineries. Optimum utilization of bio-oil fractions, processing conditions and catalyst formulations are the subjects of this research.