【作者】 逄晓翠；

【导师】 张旭；

【作者基本信息】 大连理工大学 ， 运筹学与控制论， 2009， 硕士

【摘要】 本文以甘油为底物、采用微生物歧化方法生产1,3-丙二醇的连续发酵过程为背景,基于连续发酵酶催化动力学模型,考虑胞外甘油在还原路径中的三种不同的跨膜运输方式,建立连续发酵酶催化复杂动力系统,并研究系统的基本性质。基因调控连续发酵动力系统的建立和研究为实验上采用基因敲除等技术培养高产量新菌种提供理论指导。本课题受到国家“十五”科技攻关计划项目“发酵工程生产1,3-丙二醇”(编号为2001BA708801-04)和国家高技术研究发展计划(863计划)“生物柴油与1,3-丙二醇的联产工艺”(编号为2007AA022208)的资助。此项研究将为实现1,3-丙二醇的产业化生产提供理论指导,因此,该项目研究具有重要的理论意义与应用价值。本论文的研究内容与取得的主要结果可概括如下:1、对还原路径中克雷伯氏菌胞外甘油和胞内1,3-丙二醇的跨膜运输机理进行分析和推断。在假设胞内1,3-丙二醇的跨膜运输方式为主被动结合的条件下,分别考虑胞外甘油的三种不同的跨膜运输方式(主动、被动、主被动结合),根据米氏方程建立连续发酵酶催化复杂动力系统及其参数辨识模型,证明了系统的基本性质(解的存在性和唯一性)和辨识模型的可辨识性。构造优化算法,依实验数据求得最优辨识参数。辨识后的模型中1,3-丙二醇的计算值与实验值之间的相对误差为30%左右,根据实际问题可知建立的模型适合描述连续发酵过程。2、提出生物鲁棒性分析方法。根据模型的稳定性严格依赖于动力系统敏感参数的精确数值,从对参数进行扰动的角度,建立定量的鲁棒性能指标及其优化算法。对连续发酵酶催化复杂动力系统中的三个模型分别进行鲁棒性分析,依照目标函数值,选取合理的模型去更好地反映胞外甘油的跨膜运输机理。复杂动力系统中的三个模型的鲁棒数值结果表明,参数辨识性能指标作为选取合理系统的唯一标准是不完善的,因而对模型进行鲁棒性分析是非常必要的。更多还原

【Abstract】 The enzyme-catalytic complex dynamical systems of bio-dissimilation of glycerol to 1,3-propanediol by Klebsiella pneumoniae are investigated in this paper.Basing on enzyme-catalytic kinetic model of continuous fermentation,considering the different transport ways of extracellular glycerol on the reductive pathway,the complex dynamical systems including three models are established and the properties of solutions are studied.The study of the new model can not only be helpful for deeply understanding metabolic and genetic regulation of dha regulon of glycerol metabolism,but also provide certain reference for genetic modification of Klebsiella pneumoniae.This work was supported by the tenth 5 years’ projects of Science and Technology Administration of China "Microbial Production of 1,3-Propanediol"(No.2001BA708 B01-04) and National High Technology Research and Development Program of China(863 Program)" Biodiesel and 1,3-Propanediol Integrated Production"(No.2007AA02Z208).The main results obtained in this dissertation may be summarized as follows:1.The transport mechanism of glycerol and 1,3-PD across cell membrane on the reductive pathway is analyzed and discussed.Under the assumption that 1,3-PD passes the cell membrane by both passive diffusion and active transport,considering three different transport ways of extracellular glycerol separately which are active transport,passive transport as well as active and passive transport,the enzyme-catalytic complex dynamical systems are developed by Michalis-Menten kinetics.We prove some basic properties of the systems,such as existence and uniqueness of the solution.Moreover,parameter identification models of complex dynamical systems are established and the identifiability of models is proved.The feasible optimization algorithm is constructed to find the optimal parameters for the models in accordance with the experimental data.The numerical simulation show that the relative errors between experimental and computational values of 1,3-PD is 30%or so.According to the actual biological system,the models presented in this paper are fit for formulating the factual fermentation.2.A new analysis method of biological robustness is proposed.As the stability of model depends crucially on the precise numerical values of sensitive kinetic parameters,from the perspective of a change in these parameters,a quantitative performance index of robustness and its optimization algorithm are established,then the robustness of each model in complex dynamical systems is analyzed.According to the value of objective function,we can select a reasonable system to reflect the transport mechanism of glycerol.The numerical results of robustness indicate that performance index of parameter identification is not perfect to be the unique standard to select a reasonable model,so robust analysis for each model is necessary.更多还原