Qualitative and Quantitative Assessment of Biodiesel Derived from Microalgae

Abstract

A modular experiment for upper-level undergraduate students is presented, featuring the product cycle and process evaluating the quality and quantity of biodiesel obtained from a microalgae feedstock grown under carbon-supplemented and nutrient-deprived conditions. Batch reactors are used to cultivate and harvest microalgae, which undergo acid-catalyzed in situ transesterification to produce biodiesel. Methods are presented to quantify yield and analyze products via gas chromatography–mass spectroscopy. With an awareness of the limited time available in a teaching laboratory, this experiment was designed and successfully implemented in an undergraduate biochemistry course over four sessions. Reflux reactions were performed in hermetically sealed microwave vials, eliminating water usage and reducing glass breakage. Learning objectives were assessed by postcontent quizzes, and written reports using a rubric based on Bloom’s taxonomy, results of which indicate a demonstration of the higher-order cognitive abilities of Evaluation and Analysis. The ability to biochemically engineer cultivation conditions to influence lipid production gives this experiment the potential to be offered as a course-embedded undergraduate research experience (CURE) project. This easily adoptable experiment offers an engaging opportunity for students to experience the technical and societal aspects of emerging biofuel technologies.