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

1236691 Betenbaugh/BouwerAlgae代表了液体燃料（包括柴油和喷气燃料）的潜在有价值的可再生来源。 这些液体燃料来源于藻类生物质积累过程中产生的脂质，是飞机和机动车辆使用的石油基液体燃料的替代品。 藻类生物质可以利用光合作用（光自养）、有机碳源（异养）或有机碳和阳光的组合（兼养）产生。不幸的是，仅来源于光合作用的藻类生物燃料过程通常产生少量的藻类生物质和降低的脂质产量。或者，藻类可以产生更高水平的生物质，并在补充有机碳和其他营养物质时产生高脂质产量。然而，传统有机碳源如葡萄糖的添加增加了生产成本并阻碍了商业可行性。一个同样紧迫的可持续性问题是农业、工业和城市有机废物的积累和处置所造成的环境影响和成本。该研究计划将通过将有机废物处理过程与使用微藻生物加工产生液体燃料相结合，同时解决可持续性和能源问题。 具体而言，该项目旨在改变废物处理，以产生更多的有机碳源，可供微藻消耗，并操纵微藻，使这些宿主能够消耗更多种类的来自人为有机废物的碳源。该项目的具体目标如下：1）优化环境废物处理（发酵），以产生高产量的可供微藻消耗的有机营养素; 2）从基因上操纵微藻，以使这些细胞消耗更多的有机废物副产品。在Bouwer实验室，将对有机废物处理条件（包括化学和生物预处理步骤以及碳和氮含量）进行控制，以提高有机物质转化为目标有机酸的转化率。不幸的是，虽然微藻可以消耗一些有机酸，但许多藻类无法处理来自废物处理过程的其他有机酸副产物。因此，Betenbaugh实验室项目的第二个目标是重新编程微藻细胞代谢，使它们能够消耗该物种通常不消耗的额外有机废物副产品。世界面临的三大可持续性挑战是环境污染、过度依赖不可再生化石燃料和全球变暖。长期解决办法应考虑同时处理多种可持续性问题的综合办法。该计划通过将有机液体废物处理与微藻生长和脂质生产联系起来以产生可再生液体生物燃料来解决这些挑战。微藻利用有机废物将减少威胁我们河流、湖泊和海洋的农业、工业和家庭废物径流，并将在最需要就业机会的地区创造就业机会。这项技术可以与现有的农业和家庭废物处理设施相结合，用于可再生能源发电，经济发展和社区自给自足。一个同样重要的目标将是发展一种以可持续性为重点的新的教育模式。通过与巴尔的摩少数族裔公立STEM高中的合作，学生将接受教育，使用实践方法，在基于网络和实验室的环境中，包括当地的植物园，从微藻中产生生物燃料。此外，约翰霍普金斯大学正在开发以生物能源、生物可持续性和环境恢复为重点的课堂和实验室课程。因此，拟议的项目将提供一个有价值的研究和教育平台，以培养下一代跨学科的工程师和科学家，致力于为我们星球上紧迫的可持续发展问题找到解决方案。

1236691Betenbaugh/BouwerAlgae 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.