40% of all plastic is used in packaging, a major fraction in the form of films. Most plastic films comprise multiple layers that impart desirable functionality (e.g., oxygen or moisture barriers). The currently used mechanical recycling cannot handle multilayer films. Multilayer films can be processed via pyrolysis, this, however, involves the break-down of polymers into fuel or chemical feedstock, resulting in undesirable greenhouse gas (GHG) emissions.
Plastics recycling research in our group utilizes physical, solvent-based processes whereby polymer chains do not break. This constitutes true recycling, as the recovered polymer is the same as the staring material. The objective of this project is to develop solvent-based processes to deconstruct flexible multilayer plastic films while leaving intact (in its solid form) the main component polyolefins.
The multilayer film delamination process developed here is environmentally responsible on the basis of low energy usage and GHG emissions. The recovered polyolefins, following appropriate processing, can replace primary materials without loss of properties or performance and, hence, meet demand by customers and corporations to incorporate recycled plastics into products.

Jacob Licht has earned a B.S. degree in Chemical Engineering from the University at Buffalo (UB), The State University of New York. Currently, he is a Ph.D. candidate in the Department of Chemical and Biological Engineering at UB working under the guidance of Prof. Paschalis Alexandridis and Prof. Marina Tsianou. His work investigates the delamination of multilayer plastic films to recover polyethylene with the goal of developing a scalable molecular recycling process capable of recovering polymeric materials currently being landfilled or incinerated.

• Time: 11:00 AM
• Location: 206 Furnas Hall

Glycosylation is an essential post-translational modification that regulates a variety of biological processes. An expanded toolkit of molecular probes is needed to recognize cellular glycan structures in a stereo-specific manner, as this can yield novel biomarker of cell differentiation and disease progression. Currently available lectins have shallow binding pockets and commonly exhibit broad binding specificity or only recognize terminal epitopes. Anti-carbohydrate antibodies are difficult to produce due to their low immunogenicity to glycan antigens. To address these limitations, we tested the hypothesis that mammalian glycosyltransferases can be converted into glycan binding proteins with high specificity due to their relatively deep binding pocket and selective substrate binding properties. A fusion protein was created with human IgG1 Fc N-terminally linked to pig ST3Gal1. Introduction of an H302A mutation in this construct resulted in loss of enzymatic activity but strong binding preference for sialoglycans in multiple cell types. By performing a broad CRISPR-Cas9 based library screen, studies with a panel of isogenic glycogene knockouts, and glycan microarray studies, we determined that H302A specifically binds α(2-3)sialylated core-2 O-glycans. Additionally, its binding specificity was distinct from other known sialic acid binding lectins. To expand the repertoire of lectins, a novel mammalian cell surface display platform was developed, and this was used to screen for additional H302A variants. Using a rationally designed mutant library, we identified a triple mutant of PS1, sCore2, containing H302A, A312I and F313S mutations that displayed better binding properties than H302A for sialyl-core 2 O-glycans. In spectral flow cytometry studies that analyzed glycan profiles of 35 immune cell types, sCore2 exhibited strong binding for terminal effector cell types, suggesting the high expression of sialyl-core 2 O-glycan. In human tissue microarrays, sCore2 stained various cancer tissues compared to normal tissues. In summary, we present a streamlined approach to generate glycan binding proteins based on the known substrate specificity of the starting glycosyltransferases.

Ryoma Hombu is a senior PhD candidate in Sriram Neelamegham’s lab. He is not only interested in creating novel biomolecules that exhibit new functions by utilizing protein engineering, gene editing and organic chemistry, but also applying those molecules to uncover the biological phenomenon and modify the biological components by utilizing chemical biology, glycobiology, enzymology and immunology.

He finished his master’s degree of pharmaceutical sciences in Nagoya city university in Japan. He had worked on organic chemistry to synthesize light-responsive compounds and chemical biology to apply that compound to cellular context. His current research focuses on converting glycan-processing enzyme called glycosyltransferases into glycan-binding protein with high specificity by protein engineering approach. He has delivered a presentation at 3 conferences in his PhD study and co-authored in 4 papers in his career. His current work is now under peer-review in Nature Communications and filed for US provisional patent. 

• Time: 11:00 AM
• Location: 206 Furnas Hall