共查询到17条相似文献,搜索用时 375 毫秒
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基于代谢通量分析理论研究了地衣芽孢杆菌生物合成b-甘露聚糖酶的胞内代谢活动. 首先构建了地衣芽孢杆菌产b-甘露聚糖酶的代谢网络,并依据代谢物质量平衡原则建立了反应网络的代谢流模型;进一步采用线性规划的优化方法分别以b-甘露聚糖酶合成反应通量最大和菌体生长速率最大为目标函数对模型进行求解,由此计算得到b-甘露聚糖的最大理论转化率为57.87%. 最后对代谢网络中的5个关键节点进行了比较分析,得到了2个类似非刚性的代谢节点(5-磷酸核酮糖节点和草酰乙酸节点),为利用基因工程方法提高b-甘露聚糖酶的生产能力提供了理论依据. 相似文献
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利用代谢通量分析方法,对谷氨酸棒杆菌Corynebacterium glutamicum CCTCC M201005分批发酵不同阶段和不同溶氧浓度下的代谢网络模型进行了计算,考察了代谢节点对絮凝剂REA-11合成的影响,并对C. glutamicum生长代谢过程中能量和还原力的产生及消耗问题进行分析.结果发现,磷酸戊糖途径(PP)通量在整个发酵过程中始终维持在较高的水平;REA-11合成通量随溶氧浓度的增加而降低,菌体合成通量则随溶氧水平的增加而增加;ATP通量的增加可以促进菌体生长,而与REA-11的合成呈负相关. 相似文献
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微生物细胞工厂以可再生资源为原料,实现了大宗化学品和天然产物的可持续生产,并有望替代石油化工炼制和动植物提取。剪接天然或人工代谢路径是构建微生物细胞工厂的基础。然而,剪接代谢路径造成的代谢流扰动,导致微生物细胞工厂的适配性差,降低了微生物细胞工厂的生产性能。提高人工代谢路径之间的适配性,以及人工代谢路径与底盘微生物细胞之间的适配性,将是改善微生物细胞工厂生产性能的关键。本文从强化与平衡人工代谢路径的代谢通量,解除人工代谢路径与底盘细胞内源代谢路径的交互作用,以及强化人工代谢路径与底盘细胞整体代谢网络的适配性层面,对提高微生物细胞工厂适配性的研究现状进行介绍。开发高效的多重适配性调控策略,在细胞水平重置代谢路径的适配性与提高微生物细胞对代谢产物的适配性,将是未来的研究重点。 相似文献
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将代谢工程理论应用于动物细胞的流加培养过程。通过构建代谢网络模型,研究了杂交瘤细胞从动态到拟稳态过程中物质和能量代谢通量的时间分布图。结果表明:当葡萄糖浓度较高时,葡萄糖在乳酸生成途径和TCA循环的代谢通量分配比例分别为90%和10%,ATP生成的比例分别为20%和60%,说明葡萄糖大部分经糖酵解途径生成乳酸,而进入TCA循环的少量部分则提供大部分的能量生成。当葡萄糖浓度降至其限制细胞生长的浓度时,进入TCA循环的葡萄糖比例逐步提高到100%,葡萄糖的氧化程度从0. 6 mmol·mmol-1增至4. 52 mmol·mmol-1,说明葡萄糖代谢逐渐从乳酸生成途径迁移到TCA循环,从无氧代谢逐渐转移到有氧代谢。 相似文献
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Analysis of Data on Xanthan Fermentation in Stationary Phase Using Black Box and Metabolic Network Models 下载免费PDF全文
The xanthan fermentation data in the stationary phase was analyzed using the black box and the metabolic network models. The data consistency ls checked through the elemental balance in the black box model. In the metabolic network model, the metabolic flux distribution in the cell is calculated using the metabolic flux analysis method, then the maintenance coefficients is calculated. 相似文献
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P. Ao 《Computers & Chemical Engineering》2005,29(11-12):2297
We propose to model the dynamics of metabolic networks from a systems biology point of view by four dynamical structure elements: potential function, translocation matrix, degradation matrix, and stochastic force. These four elements are balanced to determine the network dynamics, which gives arise to a special stochastic differential equation supplemented by a relationship between the stochastic force and the degradation matrix. Important network behaviors can be obtained from the potential function without explicitly solving for the time-dependent solution. The existence of such a potential function suggests a global optimization principle. The existence stochastic force corresponds naturally to the hierarchical structure in metabolic networks. We provide theoretical evidences to justify our proposal by discussing its connections to others large-scale biochemical systems approaches, such as the network thermodynamics theory, biochemical systems theory, metabolic control analysis, and flux balance analysis. Experimental data displaying stochasticity which carries important biological information are also pointed out. 相似文献
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Elementary flux mode (EFM) analysis was used in the metabolic analysis of central carbon metabolism in Saccharomyces cerevisiae based on constructed cellular network. Calculated from the metabolic model, the ethanol-producing pathway No. 37 furthest converts the substrate into ethanol among the 78 elementary flux modes. The in silico metabolic phenotypes predicted based on this analysis fit well with the fermentation performance of the engineered strains, KAM3 and KAMll, which confirmed that EFM analysis is valid to direct the construction of Saccharomyces cerevisiae engineered strains, to increase the ethanol yield. 相似文献
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J. Satya Eswari 《Chemical Engineering Communications》2016,203(3):326-338
A comprehensive metabolic network based on the fundamental pathways representing the central metabolism of rhamnolipid by Pseudomonas aeruginosa is proposed and a dynamic model compatible with the underlying metabolic network is developed involving the macro-reactions derived from the elementary flux modes of the reaction network. The experimentally validated mathematical model is then coupled with a global optimization technique called differential evolution (DE) to optimize the medium composition as well as the extracellular and intracellular fluxes of the metabolic network. The analysis of the results shows the usefulness of the integrated approach involving the development of a dynamic model based on the metabolic network structure and model-based optimization of the medium composition and metabolic fluxes by an efficient evolutionary optimization technique to enhance the productivity of rhamnolipid. 相似文献
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Claudia López Zazueta Olivier Bernard Jean-Luc Gouzé 《American Institute of Chemical Engineers》2019,65(1):18-31
Metabolic modeling has gained accuracy in the last decades, but the resulting models are of high dimension and difficult to use for control purpose. Here we propose a mathematical approach to reduce high dimensional linearized metabolic models, which relies on time scale separation and the quasi steady state assumption. Contrary to the flux balance analysis assumption that the whole system reaches an equilibrium, our reduced model depends on a small system of differential equations which represents the slow variables dynamics. Moreover, we prove that the concentration of metabolites in quasi steady state is one order of magnitude lower than the concentration of metabolites with slow dynamics (under some flux conditions). Also, we propose a minimization strategy to estimate the reduced system parameters. The reduction of a toy network with the method presented here is compared with other approaches. Finally, our reduction technique is applied to an autotrophic microalgae metabolic network. © 2018 American Institute of Chemical Engineers AIChE J, 65: 18–31, 2019 相似文献
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The stoichiometric matrix of a simplified metabolic network in Bacillus Subtillis was contructed from the flux balance equations, which were used for reconciliation of the measured rates and determination of the inner metabolic rates. Thus more reliable results of the true and empirical maintenance coefficients were obtained. The true maintenance coefficient is linearly related to the specific growth rate and changes with the P/O ratiol. The neasured biomass yield of adenosine triphosphate (ATP) is also linearly related to the P/O ratio. 相似文献