(7ix) Utilization of Lignocellulosic Biomass to Value-added Bio-products

Yoo, C. G., State University of New York College of Environmental Science and Forestry
Research Interests:

Lignocellulosic biomass, the most abundant renewable resource produced by photosynthesis on Earth, has been considered a promising alternative fuel and chemical source. It is widely accepted that biomass-derived products can reduce the current dependence on fossil-based products; however, there are still many technical and economic challenges facing the utilization of this material. My research interest in lignocellulosic biomass stems from such challenges. The long-term goal of my work is to improve the utilization of lignocellulosic biomass by understanding the physicochemical properties of this material and developing effective conversion technologies and value-added biomass-derived products.

1. Understanding the physicochemical characteristics of biomass and bio-products

Significance: Lignocellulosic biomass is a complex biopolymer mainly composed of cellulose, hemicellulose, and lignin, with other minor components. The characteristics of biomass vary depending on its species, growing environments, harvesting periods, and region. In addition, biomass conversion methods, reaction conditions, and other factors can change characteristics of the products and residues produced from biomass. Therefore, characterizing biomass and its products is essential for understanding both biomass feedstock and the effects of different conversion methods.

Current Research and Accomplishments: I have conducted a range of biomass characterization research to study the effects of different pretreatments on biomass, understand biomass recalcitrance factors in natural variants, observe the characteristic changes in genetically modified biomass, and interpret the inhibitory effects of pretreated lignins on cellulose hydrolysis. My contribution to biomass characterization has not only been limited to the collection of data or interpretation of characteristic results. I have designed a bi-solvent system to enhance biomass handling and the resolution of NMR spectra.

Future Research Plan

Based on my research experience, I believe we can find many answers for the current challenges in biomass utilization by elucidating the properties of biomass and its products. In particular, I will focus on lignin characterization because it is the key factor of biomass recalcitrance and is not a well-explored component compared to the carbohydrates fraction in lignocellulosic biomass. The following plans detail my immediate research aims for characterizing lignin, including (a) to study the relationship between the physicochemical and thermochemical properties of lignin and (b) to develop new ways of rapidly characterizing valuable technical lignins.

2. Development of effective biomass conversion processes and value-added bio-products

Significance: The conversion of lignocellulosic biomass is challenging due to its rigid and compact structure and its recalcitrant nature due to various chemical and physical features. Therefore, effective and innovative technologies are needed to convert biomass into fuels and industrial chemicals. Also, due to the technical and economic barriers of current biofuels, such as cellulosic ethanol and biodiesel, researchers have turned their attention to developing new types of biofuels, chemicals, and biomaterials from biomass.

Current Research and Accomplishments: Various pretreatment and fractionation methods have been studied for biomass utilization, but the aforementioned barriers in biomass conversion have not been fully addressed yet. For these reasons, I have tried to consider the challenges for biomass utilization by lignin valorization to mono-aromatic compounds and dicarboxylic acids. Another approach I have developed is an efficient biomass conversion process for high-value chemicals and precursors using a biphasic system that consists of an aqueous phase of molten salt hydrate and an organic phase for extracting furan-based chemicals.

Future Research Plan

My future research will aim to design practical biomass utilization strategies for industrial applications. I will approach this goal by improving biomass conversion efficiency and/or by producing high-value lignin-based products/co-products. In my previous work, I learned about the technical limitations and cost-barriers in current biomass conversion processes, thus I will focus my research group’s efforts on designing efficient biomass conversion strategies to overcome these challenges. In addition, I will develop an economic biorefinery process by valorizing co-products like lignin from current biomass conversion processes. To achieve these goals, the aims of my future research group will include: (a) to synthesize new graphene oxide-based acid catalysts for the efficient and cost-effective conversion of biomass; and (b) to produce green and high-value lignin-based biomaterials with direct commercial applications.

Research accomplishments

  • Published 32 peer-review journal articles (16 articles as a first author and 16 articles as a co-author) in Green Chemistry, ChemSusChem, ACS Sustainable Chemistry & Engineering, Bioresource Technology, Biotechnology for Biofuels, and other journals.
  • Published 3 book chapters about biomass utilization and characterization.
  • Made 20 oral and 31 poster presentations at the professional conferences including AIChE annual meeting, ACS annual meeting, Symposium on Biotechnology for Fuels and Chemicals, and others.
  • Made two invited presentations at Kongju National University and University of Tennessee-Knoxville.
  • Contributing as a Topic Editor in the Frontiers in Energy Research journal.

Teaching Interests:

My experience as a student and an instructor in academia has led me to believe that a well-prepared teacher not only delivers knowledge to students, but also utilizes a diverse number of approaches to help all students comprehend the material. In particular, higher education aims to foster professionals who have both fundamental knowledge and problem-solving skills. Therefore, effective teaching should go beyond just the delivery of knowledge. My primary goal in teaching is to provide a confident environment for students to learn fundamental knowledge and to cultivate their abilities to apply their learning and problem-solving skills at future positions. To provide this type of quality instruction, I have three key approaches: 1) motivate students; 2) interact and communicate with them in diverse ways; and 3) build their logical reasoning strategies from learning by application.

My field of research, the characterization and utilization of biomass, has attracted considerable attention due to recent global energy and environmental issues. Compared to the amount of research activity on biorenewable materials, there are generally few related courses on the subject available to students. I believe more courses are necessary to introduce biorefinery concepts and their applications, and with this in mind, I was able to contribute to the development of a “Bioprocessing and Bioproducts” course, preparing an array of course materials that spanned from the syllabus to the content for weekly lectures. It was a great experience that allowed me to think about the connection between my research and teaching. I have also taught in several lab classes designed for undergraduate students. With these experiences, I would like to develop a new course introducing and explaining biorefinery. Having written two book chapters about lignocellulosic biomass pretreatment and cellulosic ethanol production and one book chapter on biomass analysis technologies, I feel well prepared to undertake this endeavor. In particular, one of these book chapters that targeted junior and senior college students to provide fundamental knowledge about the utilization of lignocellulosic biomass is now being used in “Biorefining” course at University of Wisconsin-Madison.

I believe a well-prepared course is an excellent medium through which an instructor can provide guidance to students who can in return share their own new and creative ideas. My educational experiences have provided a valuable stepping-stone and foundation for my career to serve as a future faculty member.

Education accomplishments

  • Mentored two graduate, six undergraduate, and one high school students.
  • Gave lectures as a TA in three courses.
  • Gave lectures as a guest lecturer in two courses.
  • Organized Summer Biofuel Workshops (supported by NSF) for local high school students in two years.

Other accomplishments

  • Contributed two grant proposals (SIRE-REU; $4,865 per each project).
  • Recommended USDA 2015 AFRI NIFA Fellowship as PI ($148,515; The fellowship was not awarded because of relocation to ORNL).
  • Reviewed 3 grant proposals for USDA Small Business Innovation (SBIR) Phase I from 2015 to 2017.
  • Awarded Supplementary Performance Award ORNL (2016), Research Excellence Award (2012), Techno Dormitory Scholarship (2006), Science and Technology Scholarship (2006-2007), Hanyang Fusion Materials Scholarship (2006-2007).
  • Member of the honor societies, Gamma Sigma Delta and Alpha Epsilon.