EFRI-PSBR: Closing the loop- towards a PSBR design framework for self-sustained marine microalgal-based fuel production

作为生物燃料生产的理想原料，碱性油具有许多特点，能够利用劣质水(城市污水、微咸水等)、大气二氧化碳(CO2)，并在制备过程中重复使用烟道气中的CO2。然而，在当代光合作用生物精炼厂(PSBR)中，与培养和收获藻类相关的几个技术挑战。该项目由北卡罗来纳州立大学北卡罗来纳州立大学研究与创新新兴前沿部门和分子与细胞生物科学部联合授予北卡罗来纳州立大学的Amy Grunden、Francis de los Reyes III、Joel Ducoste、S.Ranji Ranjithan和Heike Sederoff教授，其总体目标是对可扩展的PSBR进行建模、开发、实施和评估，该PSBR使用可转换的营养循环过程，并支持在基于海洋微藻的系统中将二氧化碳高效转化为石油。利用协同工程和生物技术方法，该团队将：1)对海洋微藻物种(Dunaliella spp.)进行基因工程。该项目的主要目标是：1)通过提高二氧化碳的吸收/固定能力以及从微藻生物量中循环利用氮和磷的能力，2)设计一台小型PSBR，利用动力学模型将其用于开发基于计算流体力学模拟的PSBR可伸缩动态反应器模型；3)开发创新、可伸缩的藻类收获和脂肪提取方法；4)开发包括微藻PSBR系统灵活和可伸缩的成本和生命周期库存过程模型的生命周期分析框架。在这项工作的一个新特点中，北卡罗来纳州立大学团队计划展示新型拉格朗日微型传感器，该传感器可以根据通过反应堆的运输过程中光辐射的曝光比例来评估光辐射的累积，这将大大有助于对PSBR对光的响应进行建模和测试。因此，遗传增强、反应堆建模和生命周期评价将被用于优化PSBR中藻类生物量和脂肪的生产。Broader Impons开发真正可扩展和可持续的PSBR通过减少运输部门对化石燃料的依赖，提供巨大的经济和环境影响。创新和变革性的使能技术将允许在可扩展和可持续的PSBR中强劲地生产海洋微藻、生物质和脂肪，通过开发高效、高产的替代能源原料生产平台，将为国家带来显著的环境和经济利益。此外，通过拟议的指导和推广计划，这一涉及工程师、微生物学家、分子生物学家和植物生理学家的跨学科项目为扩大高中、本科生、研究生和博士后学者参与STEM提供了独特的机会，这些学者将被要求在传统学科之间架起桥梁，成为新一代科学家和工程师，为子孙后代开发可再生能源。具体地说，NCSU团队将与研究三角高中(RTHS，www.rthighSchool.org)的教师合作，基于PSBR技术为中学生开发可广泛分发的基于网络的教学模块。研究三角高中是一所专注于STEM的公立特许学校，服务于来自北卡罗来纳州七个县的不同人群。PIS还将为通过RTHS团队开发的为期一周的预科研究方法训练营入学的学生举办为期6周的高中生暑期研究计划。此外，该团队将推出一门新的本科专题荣誉课程-用于燃料生产的光合作用生物精炼厂，以在综合荣誉研讨会/讨论课程中培训本科生工程和生物专业学生，提供机会就与光合作用生物精炼厂设计、建模和操作相关的主题进行独立学习和团队合作。

ABSTRACT Intellectual MeritAlgal oils have many characteristics of an ideal feedstock for biofuels production, offering the ability to use poor quality water (municipal wastewater, brackish water, etc.), atmospheric carbon dioxide (CO2), and to reuse CO2 in flue gases in their preparation. However, there are several technical challenges associated with culturing and harvesting algae in current generation photosynthetic biorefineries (PSBRs). The overall goal of this project awarded jointly by NSF Emerging Frontiers in Research and Innovation Division and the Division of Molecular & Cellular Biosciences to Professors Amy Grunden, Francis de los Reyes III, Joel Ducoste, S. Ranji Ranjithan, and Heike Sederoff, all of North Carolina State University, Raleigh, NC, is to model, develop, implement, and evaluate a scalable PSBR that uses transformational nutrient recycle processes and supports efficient conversion of CO2 to oils in a marine microalgae-based system. Using synergistic engineering and biotechnological approaches, the team will: 1) genetically engineer a marine microalgae species (Dunaliella spp.) with enhanced CO2 uptake/fixation and the capability to recycle nitrogen and phosphorous from microalgal biomass; 2) design a small-scale PSBR using a kinetic model, which will be used to develop a scalable dynamic reactor model based on computational fluids dynamics simulation of the PSBR; 3) develop innovative, scalable approaches for algal harvesting and lipid extraction; and 4) develop a life-cycle analysis (LCA) framework that includes flexible and scalable cost and life-cycle inventory process models of the microalgal PSBR system. In a novel feature of the effort, the North Carolina State team plan the demonstration of novel Lagrangian microsensors that can assess accumulation of light radiation in proportion to its exposure during transport through the reactor, which will significantly aid in the modeling and testing of PSBR operation in response to light. Thus, genetic enhancement, reactor modeling, and LCA will be used to optimize the production of algal biomass and lipids in the PSBR.Broader Impacts Development of truly scalable and sustainable PSBRs offers tremendous economic and environmental impact by reducing the transportation sector reliance on fossil fuels. Innovative and transformative enabling-technologies that will permit robust production of marine microalgae biomass and lipids in scalable and sustainable PSBRs will bring significant environmental and economic benefits to the nation through the development of an efficient, high-yield alternative energy feedstock production platform. In addition, through the proposed mentoring and outreach programs, this interdisciplinary project involving engineers, microbiologists, molecular biologists, and plant physiologists provides unique opportunities for broadening STEM participation among high school, undergraduate, graduate, and postdoctoral scholars who will be required to bridge traditional disciplines and become the new generation of scientists and engineers to develop renewable energy for future generations. Specifically, the NCSU team will develop widely distributable web-based teaching modules for secondary students based on PSBR technologies in collaboration with faculty from Research Triangle High School (RTHS, www.rthighschool.org), a STEM-focused public charter school serving a diverse population from seven North Carolina counties. The PIs will also host a 6-week high school student summer research program for students that have matriculated through a 1-week preparatory Research Methods Bootcamp developed by the RTHS team. In addition, the team will introduce a new undergraduate special topics honors course, Photosynthetic Biorefineries for Fuel Production, to train undergraduate engineering and biology students in an integrated Honors seminar/discussion course providing opportunities for independent study as well as teamwork on topics relevant to photosynthetic biorefinery design, modeling, and operation.