Dimitris Argyropoulos

The objective of the project is to design a sufficiently stable microcapsule system with encapsulated agrochemical active ingredient, using cellulose-based chemistries as the principal barrier materials, with a biodegradation profile that satisfies the criteria in the ECHA ANNEX XV Proposal for a Restriction on Microplastics.

Adherence and survival of pathogens, such as bacteria and viruses, on surfaces leads to their subsequent transmission to new hosts and significantly contributes to their proliferation, which in turn considerably increases their threat to human health, especially by antibiotic resistant bacteria. Hospital acquired infections, in particular, highlight the scope of this issue: according to the CDC, about 1.7 million healthcare-associated infections cause upwards of 99,000 deaths annually in the United States. 5-10% of all hospitalized patients are adversely affected, which in turn is adding about $30-45 billion to health care costs every year. As an example, Staphylococcus aureus has been found to be able to survive for weeks and months under dry conditions on the cotton and polyester fabrics used in hospitals. Food processing, packaging and service industries, waste water treatment, daycare facilities, and personal households are other areas where infectious agents are easily spread. Consequently, more research into effective surface disinfection and alternative materials (fabrics, plastics or coatings) with antimicrobial properties is needed.

Adherence and survival of pathogens, such as bacteria and viruses, on surfaces leads to their subsequent transmission to new hosts and significantly contributes to their proliferation, which in turn considerably increases their threat to human health, especially by antibiotic resistant bacteria. Hospital acquired infections, in particular, highlight the scope of this issue: according to the CDC, about 1.7 million healthcare-associated infections cause upwards of 99,000 deaths annually in the United States. 5-10% of all hospitalized patients are adversely affected, which in turn is adding about $30-45 billion to health care costs every year. As an example, Staphylococcus aureus has been found to be able to survive for weeks and months under dry conditions on the cotton and polyester fabrics used in hospitals. Food processing, packaging and service industries, waste water treatment, daycare facilities, and personal households are other areas where infectious agents are easily spread. Consequently, more research into effective surface disinfection and alternative materials (fabrics, plastics or coatings) with antimicrobial properties is needed. The technology development proposed herein will expand the application of nanofibrillated cellulose in which are embedded photosensitizers (chemical compounds that react with light), thereby leading to novel photoactive coatings capable of being sprayed or applied as a coating to existing materials (or used in 3D printing), and that are capable of rapid, efficient, and low-cost sterilization of a range of infective agents. The objective of this CIF proposal is to acquire data necessary for commercialization of nanofibrillated cellulose embedded with photosensitizers as anti-infective materials, specifically to demonstrate that they are active against bacteria and fungi that together represent the five classes of antibiotic-resistant pathogens that are emerging as major public health threats (vancomycin-resistant Enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant mycobacteria, Gram-negative bacteria, and fungi), and also are highly effective against viruses. The funding provided will enable our interdisciplinary research program to provide the proof-of-principal to demonstrate their commercial applicability as anti-infectives in the health care, textiles, and food preparation industries.

Adherence and survival of infective agents on surfaces leads to their transmission to new hosts and significantly contributes to pathogen proliferation, which in turn considerably increases the threat to human health, especially by drug-resistant strains. Consequently, more research into effective surface disinfection by alternative materials (fabrics, plastics or coatings) with anti-infective properties are needed. The research proposed herein describes the application of cellulose (nanocrystals and paper) that are modified with porphyrins, thereby leading to novel photoactive materials capable of rapid, efficient, and low-cost sterilization of a range of bacteria, fungi and viruses. The funding provided by this grant will enable our interdisciplinary research program between the Departments of Chemistry (Sciences), Forest Biomaterials (CNR), and Biological Sciences (Sciences) to develop anti-infective materials useful for the health care, textiles, and food preparation industries.

The goal of this work is to help investigate and analyze the reactivity and value of a series of woody biomass materials provided by BioOil AS. NCSU will help define the experiments and work BioOil AS partners to insure that the samples are prepared and stored in a realistic and reliable manner. NCSU will also investigate options for separating the major biomass components, cellulose, hemicellulose, lignin and extractives to recover these individual components, and determine the reactivity of the isolated carbohydrates for producing sugars that can be used as a fermentation feedstock. NCSU will also investigate the use of the isolated lignin component for value added applications, specifically their performance in phenol formaldehyde resins. Finally, using data from the experimental work NCSU will assist with modeling the integrated process to determine the mass and energy flows for the different unit operations.

Most efforts to utilize lignin previously have been limited by various factors that impart in lignin characteristics that define it as an unreliable precursor to polymer production. This is because lignin (and more specifically technical kraft lignin) offers relatively unpredictable polymerization characteristics, depending upon its source, the pulping (or other process) from which the lignin arises, and the degree of delignification to which the plant materials were subjected. Heating of lignin at an elevated temperature converts it to a condensed from and makes it rigid and less reactive. The irreversible formation of such gels precludes lignin from becoming and being considered as an integral part of modern synthetic polymer and composite production lines. In addition, the relatively low molecular weight (a few thousands) for lignin derived from commercial pulping and biorefinery operations makes lignin unsuitable for higher end applications, such, for example, high performance, heat stable engineering thermoplastic and textile fiber applications. Our work can be characterized in that technical kraft lignins will be structurally modified so as to form lignins of modulated reactivity by the selective masking procedures preparing them for subsequent copolymerization chemistries. The thus formed, masked lignins will exhibit modulated characteristics making them highly useful components for automotive, stable melts for carbon fiber pre-polymers and thermoplastic copolymers for textile application. As such, the present effort will provide a significant advancement in lignin chemistry that allows significant flexibility in selecting the lignin source and in tuning the eventual polymer properties to desired and pre-defined characteristics. This will be achieved while simultaneously preventing the lignin from becoming a gel during polymerization, which is a phenomenon that has previously significantly limited the usefulness of technical lignins in preparing high value polymers.

Under the IUCRC membership agreement NCSU will focus on developing engineering process models that can be used to evaluate the mass and energy balances within the integrated biorefinery. These engineering process models, developed with common commercial software packages, can be used to evaluate different configurations of the key unit operations, and minimize the energy demands and operational costs. They can also be used by BioOil to estimate the capital costs of the biorefinery options. These process models will include many common unit operations, or blocks, including ethanol recovery using distillation and pervaporation, biomass pretreatment, lignin isolation and recovery, enzyme hydrolysis, mixed sugar fermentation, waste-water treatment, biomass power boiler and stream/power generation. To accomplish these overall goals, BioOil has joined the NSF Industry University Cooperative Research Center for Bioenergy Research and Development (CBeRD). Other CBeRD member companies are also developing process models and tools that can provide additional information and insights into the BioOil AS processes.

This project seeks to exploit feasible chemical modifications during kraft pulping operations to obtain significant energy and product benefits for US kraft pulp and paper mills. The project will focus on providing a cost effective retro-modification to kraft pulp mills (linerboard and bleachable grades) that will improve the energy efficiency and productivity of mills. It will do this by rerouting a significant portion (20-30 %) of the green liquor (GL) flow from causticizing to the pulp digester. The originally funded DOE project (Novel Pulping Technology: Directed Green Liquor Utilization [D-GLU] Pulping) determined that the GL pretreatment technology that was successfully applied in UPM-Kymmene mills in Finland does provide important energy benefits for US mills employing typical North American furnishes, in particular Southern pine. At the conclusion of the first project, we were able to determine that an inexpensive ($0.19/lb) organic additive (thiourea) can enhance the pulping benefits in a manner similar to AQ. The ultimate purpose of the proposed project will be to intensively collaborate during the next four years with our sponsor mill in Samoa, CA who has expressed interest in implementing this technology. We have assembled a diverse team that includes expertise in wood chemistry, environmental engineering, chemical engineering, and pulping and bleaching that is headed at the North Carolina State University and includes the Georgia Institute of Technology. We anticipate that this proposal will address the major front end issues to implementation over the first two years with guidance from our sponsors and then tackle the logistics of mill implementation along with secondary issues including pulp qualities and characteristics, odor, and corrosion.

Our proposal is aimed at exploring the use of supercritical oxidation technologies for fragmenting and converting lignins into high value, low molecular weight chemicals that could be used as precursors to the adhesives, plastics, detergents, pharmaceutical, flavor and fragrance, metal chelants, polyurethane, antioxidant and other chemical industries. The project will use softwood and hardwood lignin streams that emerge from modern biomass/bio-energy saccharification treatments as well as organosolv pulping and kraft lignin streams. Our feasibility study has shown that it is possible to oxidize recalcitrant residual kraft lignin in scCO2 in total absence of alkali. This highly valuable piece of scientific information when coupled with the multitude of attractive features and recent advances in supercritical technologies and catalytic science, offers some very exciting prospects. Namely, the development of new, environmentally benign, fragmentation technologies that do not require alkali and solvents. This will add value to lignin streams which are currently underutilized or in need of new markets. Initially our project aims at isolating, characterizing and defining lignin fractions via ultrafiltration and studying their solubilities in scCO2, in the presence and absence of co-solvents as well as CO2-expanded liquids. We then intend to chart the reaction pathways that occur when selected lignins are subjected to peroxide induced oxidative degradations in the systems identified. The reaction pathways that occur when lignins are subjected to dioxygen induced oxidative degradations in the presence of catalysts solubilized in CO2-expanded liquids will also be examined by quadrupole mass spectrometry. In addition, the concerted use of scCO2 oxidative degradation and sonication technologies will be explored with the aim to produce useful low molecular weight chemicals and functional monomers in good yields. Finally, once the characterization data has been fully accumulated, our efforts will be directed towards optimizing the various reactions for the production of the identified valuable chemicals. Overall, this project will reveal the ultimate potential of scCO2 oxidative chemistry when applied to lignins. This effort in conjunction with modern biomass/bio-energy saccharification technologies will form the foundations of a novel, environmentally friendly process for adding value to lignins.

Ionic Liquids (ILs) are organic salts that are liquid at or near room temperature. They remain liquid over a wide temperature range (about 300?aC), and are thermally stable up to 200?aC. Ionic liquids are non-volatile and non-flammable, and are considered to be environmentally friendly alternatives to volatile organic compounds and suitable solvents for ?green? physical and chemical processing, including separations, extractions, and for (bio)chemical reactions [6]. Recently, it has been reported that ILs have the potential to act as mustard gas neutralizers as shown by the work of Voss et al. and http://www.af.mil/news/story.asp?id=123195755. The action is predicated on a nucleophilic reaction. However, the down side of using ILs for chemical warfare agent decontamination is related to their relative high viscosity if they are used in the pure state which may complicate their processing to treat large surfaces. Also due to their high solvation capacity and depending on their nature, they may cause damage to indoor surfaces. Finally, the cost related to their production makes them too expensive if they are used alone in large volume. Inspired from the above mentioned examples and taking advantage of capability of IL to neutralize chemical warfare as mentioned earlier, our approach is therefore to incorporate ILs in a polymer matrix to manufacture a solid composite material that displays anti-chemical warfare agent activity. The targeted active sorbent material will have high absorbent capability, porous structure, be easy to process, easy to handle, and be eco-friendly. These characteristics are determined by the nature of the polymeric matrix to be used. In our case, we will focus on the use of a polymer, cellulose, which originates from renewable resources. This green approach to anti-chemical warfare is feasible and may be potentially more powerful than current technologies used in the military mentioned earlier (vide infra).