Rational Design of Optimal Cellulase Enzyme System for Biofuels Production

PI: Murthy， GantiProposal Number: 1236349Institution: Oregon State university标题：用于生物燃料生产的最佳纤维素酶系统的合理设计虽然先进的生物燃料有可能减少对化石燃料的依赖和温室气体的排放，但由于生产和将原料转化为生物燃料的各种挑战，这还没有实现。该建议解决了原料转化中的一些挑战。许多研究人员已经证明，纤维素酶的高价格高达每加仑乙醇1美元（乙醇生产成本的30-35%）是先进生物燃料商业化的绊脚石。任何能够降低这些成本的策略都可能对纤维素乙醇生产的经济效益产生重大而直接的实际影响。纤维素是地球上最丰富的生物聚合物，被许多生物代谢，因此自然界中存在着各种各样的纤维素酶。利用这种广泛的纤维素酶来生产先进的生物燃料是具有挑战性的，因为许多这些酶具有不同的作用模式、温度和最佳pH值。目前确定最佳酶比的唯一方法是用不同的底物进行广泛的实验。迫切需要开发一种合理的设计框架，可以优化不同纤维素酶的混合物，受各种工艺，经济约束；从而大大降低了乙醇生产过程中使用的酶的总成本。本综合建议的总体目标是利用随机/动力学模型和控制理论方法开发合理设计纤维素酶的方法。使用控制理论工具分析复杂生化系统的新方法将得到发展。这些分析方法在生物加工和生物燃料生产中具有广泛的应用前景。这些技术将在使用纯酶和商业酶混合物的实验室规模系统上进行演示。本项目将利用随机建模技术和控制理论方法的动力学模型来开发一个合理设计纤维素酶的框架。由于纤维素水解在多种酶协同作用下有效进行，多种酶的作用将使用两种方法建模：动力学模型和随机分子模拟模型。线性和非线性控制理论方法将以一种新的方式应用于识别和量化各种设计约束下的最佳酶组成。控制理论技术将用于评估最佳酶组合物在实际应用中的适用性。这个理论框架也可以用来帮助模型驱动的假设公式的设计纤维素酶混合物，可以通过实验验证。在这个项目中开发的分析技术将在生物加工和生物燃料生产领域得到应用。本项目的主要工作是为研究生、本科生和高中生提供结构化的培训和指导计划、课程开发和推广计划，以广泛传播本项目开发的知识。将开设一门新的研究生水平课程，并为现有的本科课程开设一个实验室部分。将开发一个专门的网站，以便有效地传播本项目编制的课程材料。研究生和本科生将直接接受研究方法方面的指导和培训，以建立知识库，并作为进一步创新的催化剂。

PI: Murthy, GantiProposal Number: 1236349Institution: Oregon State UniversityTitle: Rational Design of Optimal Cellulase Enzyme System for Biofuels ProductionWhile advanced biofuels have potential to reduce dependence on fossil fuels and emissions of greenhouse gases, this has not been realized due to various challenges in production and conversion of feedstock into biofuels. This proposal addresses some of the challenges in the conversion of feedstock. Many researchers have demonstrated that the high price of cellulase enzymes up to $1/gal of ethanol (30-35% of ethanol production costs) is a stumbling block for commercialization of advanced biofuels. Any strategy that can reduce these costs could have significant and immediate practical impact on economics of cellulosic ethanol production. As cellulose is the most abundant biopolymer on earth that is metabolized by many organisms, a wide variety of cellulase enzymes exist in nature. Utilization of this wide array of cellulases for advanced biofuels production is challenging as many of these enzymes have different modes of action, temperature and pH optima. Currently the only way to determine the optimum enzyme ratio is to perform extensive experiments with different substrates. There is a critical need to develop a rational design framework that can optimize the mixture of different cellulase enzymes subject to various process, economic constraints; thus significantly reducing the total cost of enzymes used in ethanol production process.The overall goal of this integrated proposal is to develop methods for rational design of cellulase enzymes using stochastic/kinetic models and control theoretic approaches. New methods of analysis for complex biochemical systems using tools from control theory will be developed. These analytical methods will have wide ranging application in bioprocessing and biofuels production. These techniques will be demonstrated on a laboratory scale system using pure enzymes and commercial enzyme mixtures.This project will utilize stochastic modeling techniques and kinetic models with control theory approaches to develop a framework for rational design of cellulase enzymes. Since cellulose hydrolysis proceeds efficiently in the presence of multiple enzymes working in a synergistic manner, action of multiple enzymes will be modeled using two approaches: Kinetic models and stochastic molecular simulation models. Linear and nonlinear control theory methods will be applied in a novel way to identify and quantify the optimal enzyme composition for various design constraints. Control theory techniques will be used to evaluate the suitability of the optimal enzyme compositions for real world applications. This theoretical framework can also be used to aid model driven hypothesis formulation for design of cellulase mixtures that can be experimentally verified. Analysis techniques that will be developed in this project will have applications in the areas of bioprocessing and biofuels production.A significant effort in this project will be devoted for conducting structured training and mentoring programs for graduate, undergraduate and high school students, curriculum development and outreach programs for wide dissemination of knowledge developed in this project. One new graduate level course will be developed and a laboratory section will be developed for an existing undergraduate course. A dedicated website will be developed for effective dissemination of the course materials developed in this project. Graduate and undergraduate students will be directly mentored and trained in research methods to create a knowledge base and serve as a catalyst for further innovation.