Applying Mass Balances To Alcohol Metabolism: A Team Project That Applies Fundamental Chemical Engineering Skills To Biotechnology

In the last decade, chemical engineering has evolved to meet the growing challenges of the 21 st century, particularly in the areas of biotechnology and sustainable development. However, the chemical engineering curriculum has somewhat lagged in integrating and reflecting these modern topics. Approximately 30% of students entering our Mass and Energy Balances class list interests in biologically-related topics (pharmaceutical, biomedical, medical, environmental) versus about 10% each for industry, energy, research, and other, with 20 % undecided, and about 10% non-respondents (mostly non-chemical engineering undergrads). This traditional gateway course needs to continually evolve to develop student awareness of the current issues, excite their interest in finding solutions to challenges that face their generation, and engage them in learning the required fundamental skills to find those solutions. Topics on biotechnology were absent in the course initially, and as we investigated ways to integrate these topics into the class we found that there was a paucity of published biochemical-themed projects for a sophomorelevel mass balance curriculum. This challenged us to develop a new team project that incorporates biotechnology. We chose to apply mass balances to human alcohol metabolism. Student teams create a mass balance model of the breakdown of ethanol within the human body using computer spreadsheets to calculate mass flow rates to and from key organs. Process units model the organs handling biological functions such as oxygen and liquid intake, chemical breakdown, and waste removal. The project requires only knowledge of multi-unit mass balances and chemical reactions in the steady state; parameters are designed to create reasonable physiological results from their model. Students test their model using an established basis and monitor variables such as blood alcohol concentration and blood acetaldehyde concentration. Students investigate “Asian blush”, a physiological syndrome resulting from different enzymatic degradation of ethanol in some Asian populations compared to those of European descent, thus introducing the students to human health issues. Students then scale their model from human proportions down to a microscale lab-on-a-chip device, a so-called “body-on-a-chip”, which is an in vitro platform that is used for testing metabolic effects of various chemicals. With the premise of working as consultants for a pharmaceutical company, students study a fictional drug which is supposed to suppress alcoholism by artificially increasing alcohol sensitivity. Student groups are assigned different formulations, each altering different parameters in their mass balance model, and are asked to analyze the effects of their drug to determine its efficacy. Formulations can vary from detrimental to beneficial, requiring students to develop analytical skills and engineering judgment as they assess the drug performance. By combining computer technology and biochemical principles, we created a self-contained, group, project module which introduces students to a number of different biotechnological and human health issues, and develops critical thinking, team work, and communication skills. This project addresses students’ professional interests, engages them in active learning, and reinforces the mass balance fundamentals that are building blocks for subsequent courses in the chemical engineering curriculum.