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ChE Majors Tjo and Voke Take Second-place Awards During AIChE Conference Poster Contest

Susan Perry and students at AIChE conference

From left: Hansen Tjo and Elizabeth Voke

Chemical Engineering (ChE) majors Hansen Tjo and Elizabeth Voke each won second-place awards in the undergraduate poster contest at the annual conference of the American Institute of Chemical Engineers (AIChE) in Orlando, Florida, from November 10 to 15. The ChE department helped to send 10 ChE majors to the conference, at which Hansen finished second in the Materials Science & Engineering category, and Elizabeth won second place in the Food, Pharmaceuticals, and Biotech classification.

Hansen’s award-winning poster described his research with ChE doctoral student Whitney C. Blocher McTigue and ChE faculty advisor Professor Sarah Perry on “Predicting Polyelectrolyte-Micelle Phase Transitions: A Study in Charge Densities.”

As Hansen and his research associates concluded, “The results from this study will broaden the array of polyelectrolyte-micelle systems for applications such as biomolecular encapsulation and drug delivery.”

According to Hansen and colleagues, the widespread applications of coacervates for molecular separation and controlled delivery have resulted in extensive analysis of the phase behavior and properties of polyelectrolyte-micelle systems. However, much of the work to date has focused primarily on the effects of micellar surface-charge density with model polymer-surfactant complexes.

“Thus, our objective is to explore the effects of stoichiometry and micellar chemistry over a larger phase space, with the goal of constructing a predictive framework for polyelectrolyte-micelle phase separation based on species’ charge densities,” wrote Hansen and colleagues.

"Here," the researchers added, "we mapped the phase behavior of (model) complexes between the polycation poly (diallyldimethylammonium chloride) with surfactant micelles containing a mixture of the anionic surfactant sodium dodecyl sulfate and the neutral surfactant Triton X-100 as a function of composition and salt concentration. These morphology maps will act as a key reference for phase transitions in polymer-micelle systems."

Elizabeth Voke’s research could have repercussions on such pharmaceuticals as antibiotics and anticancer and immunosuppressant drugs. Her research involves the development of Mycobacterium smegmatis as a host strain for polyketide synthase production, a study done during the 2019 Amgen Scholars Summer Research Program in conjunction with Luis Valencia and Professor Jay Keasling of the Department of Chemical and Biomolecular Engineering at the University of California, Berkeley.

According to Elizabeth’s abstract, polyketide synthases (PKSs) are enzymes that synthesize a biologically important family of complex chemicals called polyketides, which include various antibiotics, anticancer, and immunosuppressant drugs. Due to their highly complex architectures, polyketides are difficult to synthesize via traditional organic chemistry means.

According to the abstract, through bioengineering, scientists have been able to genetically modify polyketide synthases to selectively produce polyketides of interest such as adipic acid, methyl ketones, and chiral building blocks. However, commonly used heterologous hosts for PKS production, such as Escherichia coli (E. coli) and Streptomyces, can be inefficient and challenging to manipulate.

“In response to this need,” explained Elizabeth and her colleagues, “we seek to develop Mycobacterium smegmatis as a new PKS host due to its more easily manipulated genome, availability of genetic tools,  relatively fast growth rate, and ability to naturally produce precursors for biosynthesis.”

The experience at the AIChE conference proved invaluable for all the ChE students who attended, with financial help from the ChE Department.

“It was an extremely valuable experience for all 10 students that went,” wrote the UMass AIChE student chapter in a letter to ChE Department Head John Klier while thanking him for the opportunity. “We took advantage of a career/graduate school fair, participated in workshops, and even represented UMass at the annual jeopardy competition, which we qualified for last year. We had a great time and are very thankful for this experience. We would not have been able to attend without your help.” (January 2020)

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