Ecological and Engineering Approaches to Optimizing Algal Biofuels

Abstract

Algae are ubiquitous in natural ecosystems and have been studied extensively due to their versatility for biofuel production. Most of these studies have been conducted on the grounds of synthetic biology and process engineering with few industrial scale projects considering algal community interactions. Such interactions have often indicated the propensity of increasing overall productivity and reducing community invasability, both important characteristics for scalable projects. However, over 30,000 species of algae have currently been identified with another 20,000 estimated to exist. Within this context, elucidation of these relationships remains extremely resource and time intensive. This thesis outlines a strategy for rapid, high-throughput screening of algal community combinations using a microfluidic platform to synthesize millions of parallel, nanoliter-scale algal communities for analysis of biomass accumulation. Model communities were first studied in a bench scale flask experiment and then examined using microfluidic droplets. These experiments showed consistent results on both positively and negatively interacting algal bicultures. Specifically, these include better performance within bicultures of Ankistrodesmus falcatus and Chlorella sorokiniana as well as Chlorella sorokiniana and Selenastrum minutum with lower performance within the biculture of Selenastrum capricornutum and Scenedesmus ecornis. Biofuels provide a unique opportunity for market penetration in one dominated by petroleum based fossil fuels. They serve as renewable and significantly less carbon intensive alternatives. While the holistic success of algal biofuels will hinge on an amalgamation of these scientific fields, rapid screening of algal communities could prove imperative for discovering community interactions and ideally facilitating a mechanistic analysis of how such interactions arise in natural communities.