Sustainable Bioconversion of Liquid Biofuels: Linking Organic Waste Processing and Microalgae Cultivation

Johns Hopkins University, Baltimore MD

Investigators

Abstract

1236691 Betenbaugh/Bouwer Algae represent a potentially valuable renewable source of liquid fuels including diesel and jet fuel. These liquid fuels are derived from the lipids generated during the accumulation of algal biomass and represent an alternative to petroleum-based liquid fuels for airplanes and motor vehicles. Algal biomass can be generated using photosynthesis (photoautotrophy), with organic carbon sources (heterotrophy), or using a combination of organic carbon and sunlight (mixotrophy). Unfortunately, algal biofuel processes derived from photosynthesis alone typically generate low amounts of algal biomass and reduced yields of the lipids. Alternatively, algae can generate much higher levels of biomass and produce high lipid yields when supplemented with organic carbon and other nutrients. However, the addition of traditional organic carbon sources such as glucose increases production costs and hinders commercial feasibility. An equally pressing sustainability problem is the environmental impacts and costs resulting from the accumulation and disposal of agricultural, industrial, and municipal organic wastes. This research program will simultaneously address both sustainability and energy issues by combining organic waste treatment processes with the generation of liquid fuels using microalgal bioprocessing. Specifically the project aims to alter waste treatment in order to generate increased amounts of organic carbon sources that can be consumed by microalgae and to manipulate microalgae to enable these hosts to consume a greater variety of carbon sources available from anthropogenic organic wastes. The specific objectives of the project are as follows: 1) Optimize environmental waste processing (fermentation) to generate high yields of organic nutrients that can be consumed by microalgae; 2) Manipulate microalgae genetically in order to allow these cells to consume a larger number of organic waste by-products. In the Bouwer laboratories, organic waste processing conditions including chemical and biological pretreatment steps as well as carbon and nitrogen content will be manipulated in order to increase organic matter conversion to target organic acids. Unfortunately, while microalgae can consume some organic acids, many algae are unable to process other organic acid by-products from waste treatment processes. Therefore, the second aim of the project in the Betenbaugh laboratory is to reprogram microalgae cellular metabolism to enable them to consume additional organic waste by-products that the species do not typically consume. Three of the greatest sustainability challenges facing the world are pollution of the environment, over-reliance on non-renewable fossil fuels, and global warming. Long-term solutions should consider holistic approaches that address multiple sustainability issues simultaneously. This program addresses these challenges by linking organic liquid waste disposal with microalgae growth and lipids production for the generation of renewable liquid biofuels. Utilization of organic wastes by microalgae will reduce agricultural, industrial and domestic waste runoff that threatens our rivers, lakes, and oceans and will lead to the creation of jobs in areas where the employment opportunities are most needed. This technology can integrate with existing agricultural and domestic waste-treatment facilities for renewable energy generation, economic development, and community self-sufficiency. An equally important goal will be the development of a new education paradigm focused on sustainability. Through a partnership with Baltimore's minority public STEM high schools, students will be educated using hands-on approaches to generate biofuels from microalgae in web-based and laboratory settings including a local arboretum. In addition, classroom and laboratory courses focused on bioenergy, biosustainability, and environmental recovery are under development at Johns Hopkins University. Thus, the proposed project will provide a valuable research and education platform to train the next generation of cross-disciplinary engineers and scientists dedicated to finding solutions to pressing sustainability issues on our planet.