Beyond the Monod Equation: Developing a New Theory of Geomicrobial Kinetics

超越莫诺方程：发展一种新的地球微生物动力学理论

• 批准号: 0819954
• 负责人: Qusheng Jin
• 金额: $ 30万
• 依托单位: University of Oregon Eugene
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0819954&HistoricalAwards=false
• 关键词: Beyond; Monod; Equation; Developing; New

Intellectual Merit: The primary objective of this proposal is to develop a new rate law for the kinetics of microbial metabolisms in geological environments. The new rate law will advance the study of geobiology and biogeochemistry by accounting for how available energy and microbial diversity control the progress of microbial metabolisms in geological environments. Investigators will develop the new rate law based on: (1) a theoretical model for thermodynamic control of microbial metabolisms; (2) limits to microbial kinetic parameters derived from collision theory and the minimum requirements for microbial growth; and (3) the diversity and abundance of microbial taxonomic groups in the environment. These three bases of the new rate law lead to three primary research tasks: (1) quantifying the significance of thermodynamic control on microbial metabolisms in geological environments; (2) developing a theoretical approach that integrates microbial diversity into kinetic rate laws; and (3) comparing the performance of the new model to traditional kinetic models (i.e., the Monod equation) by comparing the output of both models to in situ rates of methanogenesis as a test case. They will develop the new rate law and apply it to predicting the seasonal rates of methanogenesis in the sediments of Upper Klamath Lake in southcentral Oregon. Their preliminary results demonstrate modest methanogen diversity but significant rates of methanogenesis. Seasonal variation in organic matter loading into these sediments leads to a wide range in electron donor concentrations, offering a natural experiment for developing our new theory of geomicrobial kinetics. The new rate law developed in this proposal accounts for two critical, yet largely neglected, controlling factors on biogeochemical processes in the environment, i.e., the availability of chemical energy and the diversity of microorganisms. The new rate law therefore bridges the gap between empirical rate laws (e.g., the Monod equation) applicable for pure-cultures under energy-rich conditions and the kinetics of diverse microorganisms in geological environments. The new theory integrates geochemistry and microbial diversity into geomicrobial kinetics and, therefore, advances ongoing research efforts that seek to understand geological environments as habitats for diverse microorganisms. The new theory can be applied to the prediction of microbial activities in both natural environments and polluted areas, or in remote sites where direct sampling is not feasible. Broader Impacts: The proposed research addresses a compelling question in geobiology and biogeochemistry − how to predict the activities of diverse microorganisms in geological environments? Investigators will use our multidisciplinary approach to provide learning opportunities at all levels from K-12 to postgraduate. They will collaborate with science instructors at a high school near the field site to develop a sustainable and replicable classroom unit on the kinetics of methanogenesis and the carbon cycle. This unit will be inquiry-based and will introduce students to environmental science via a series of hands-on field and laboratory experiences centered on a common theme ? the cycling of carbon in Oregon lakes. The unit will be distributed to all Oregon K-12 educators, and it will be designed to meet a new requirement of the Oregon State Board of Education for additional inquiry-based science instruction in Oregon public schools. The proposed project will support two Ph.D. students. PIs will also recruit three to four undergraduate students into our research program via the support of the NSF-funded Undergraduate Catalytic Outreach and Research Experiences program and the Summer Program for Undergraduate Research at the University of Oregon.

智力优势：该提案的主要目的是为地质环境中微生物代谢的动力学发展一种新的速率定律。新的速率定律将通过解释可利用的能量和微生物多样性如何控制地质环境中微生物代谢的进展来推进地球生物学和地球化学的研究。研究人员将根据以下方面制定新的速率定律：（1）微生物代谢热力学控制的理论模型;（2）来自碰撞理论的微生物动力学参数的限制和微生物生长的最低要求;（3）环境中微生物分类群的多样性和丰度。新速率定律的这三个基础导致了三个主要的研究任务：（1）量化地质环境中微生物代谢的热力学控制的意义;（2）开发将微生物多样性整合到动力学速率定律中的理论方法;（3）将新模型的性能与传统动力学模型（即，Monod方程）通过将两个模型的输出与作为测试情况的甲烷生成的原位速率进行比较。他们将开发新的速率定律，并将其应用于预测俄勒冈州中南部上克拉马斯湖沉积物中甲烷生成的季节性速率。他们的初步结果表明，适度的产甲烷菌多样性，但显着的产甲烷率。有机物载入这些沉积物中的季节性变化导致电子供体浓度范围很广，为发展我们的新理论提供了一个自然的实验地质微生物动力学。本提案中提出的新速率定律说明了环境中生物地球化学过程的两个关键但在很大程度上被忽视的控制因素，即，化学能的可利用性和微生物的多样性。因此，新的速率定律弥合了经验速率定律之间的差距（例如，Monod方程），适用于能源丰富的条件下的纯培养物和地质环境中各种微生物的动力学。新理论将地球化学和微生物多样性整合到地质微生物动力学中，因此，推进了正在进行的研究工作，试图了解地质环境作为不同微生物的栖息地。新的理论可以应用于自然环境和污染地区的微生物活动的预测，或在偏远地区直接采样是不可行的。更广泛的影响：拟议的研究解决了地球生物学和地球化学中一个引人注目的问题#8722;如何预测地质环境中不同微生物的活动？调查人员将使用我们的多学科方法，提供从K-12到研究生的各级学习机会。他们将与现场附近一所高中的科学教师合作，开发一个关于甲烷生成和碳循环动力学的可持续和可复制的课堂单元。本单元将以探究为基础，通过一系列围绕一个共同主题的实地和实验室实践经验，向学生介绍环境科学。碳在俄勒冈州湖泊中的循环。该单位将分发给所有俄勒冈州K-12教育工作者，它将被设计为满足俄勒冈州教育委员会的一个新的要求，在俄勒冈州公立学校额外的调查为基础的科学教学。该项目将资助两名博士。学生PI还将通过NSF资助的本科催化推广和研究经验计划以及俄勒冈州大学本科研究暑期计划的支持，招募三到四名本科生进入我们的研究计划。