重组毕赤酵母产青霉素G酰化酶的分批发酵动力学研究

构建了重组毕赤酵母产青霉素G酰化酶的分批发酵动力学模型。实验考察了分批发酵过程中甘油消耗、甲醇浓度、菌体浓度、溶氧、补料时间对青霉素G酰化酶活力的影响。应用Matlab软件,对菌体生长、基质消耗和产物生成方程进行最优参数估算和非线性拟合,得到相应的动力学模型。模型的计算值与实验值能较好地拟合,表明所建模型能较好反映重组毕赤酵母产青霉素G酰化酶的分批发酵过程。     

蓝色犁头霉深层发酵产壳低聚糖生长动力学研究

目的:研究蓝色犁头霉产壳低聚糖分批发酵动力学的模型.方法:在10L发酵罐中,将蓝色犁头霉分批发酵培养,对蓝色犁头霉菌丝体生长、产物形成和基质消耗的实验数据进行分析,根据Logistic和Luedeking-Piret方程分别建立蓝色犁头霉发酵过程菌体生长、壳低聚糖生成和基质消耗的动力学数学模型,并利用1stOpt软件对模型参数进行非线性曲线拟合.结果:研究得到了菌体生长、产物合成及基质消耗的动力学模型及参数,模型的拟合度分别为0.994、0.986、0.992.结论:研究表明蓝色犁头霉多糖合成和菌体生长呈生长偶联型,模型计算值与实验值有良好的拟合性,模型准确度较高.     

黑曲霉产糖化酶黑箱模型的构建和应用

利用碳限制恒化实验研究了黑曲霉生长和糖化酶生产之间的相关性,结果表明当比生长速率低于0.068 h–1时,菌体生长与产酶是相关的,当比生长速率大于0.068 h–1时,菌体生长与产酶不相关。根据恒化实验结果获得黑曲霉葡萄糖底物消耗的Monod动力学模型,并结合葡萄糖和氧消耗的Herbert-Pirt方程和产物形成的Luedeking-Piret方程构建黑曲霉产糖化酶的黑箱模型。应用该模型设计指数补料分批发酵实验控制菌体比生长速率在0.05 h–1,使糖化酶的得率最高达到0.127 g糖化酶/g葡萄糖,并成功地使用模型描述了黑曲霉产糖化酶的发酵过程。实验值和模拟值进行比较表现出很好的适用性,表明黑箱模型可以用于指导黑曲霉产糖化酶发酵过程的设计和优化。     

黑曲霉过氧化氢酶发酵过程的数学模型

研究了黑曲霉发酵生产过程氧化氢酶的分批发酵动力学,并建立了发酵过程菌体生长,基质消耗及酶合成的随时间变化的数学模型。Logistic方程,Luedekin-Piret方程及与Luedeking-Piret方程相似的基质消耗方程能够很好地分别描述黑曲霉细胞的生长,发酵产酶过程及葡萄糖的消耗,过氧化氢酶的发酵合成是生长耦联的,研究中还将3个动力学模型的预测值和实验值进行了比较。     

Kinetic model for nuclease P1fermentation by Penicillium citrinum

研究了桔青霉发酵生产核酸酶P1的发酵动力学特性:以Logistic方程和Luedeking-Piret方程为基础,进行最优参数估计和非线性拟合,得到了描述整个发酵过程中的菌体生长、产物合成和基质消耗的动力学模型.对实验数据与模型预测值进行比较,发现模型预测值与实验数据能较好地拟合,基本上反映了桔青霉发酵过程的动力学特征,为以后进一步研究和预测核酸酶P1发酵过程奠定了理论基础.     

产弹性蛋白酶细菌的发酵动力学研究

基于14L的发酵罐分批发酵实验数据,建立了发酵过程菌体生长、产物生成及基质消耗随时间变化的数学模型。Logistic方程、Luedeking—Piret方程能够很好地分别描述产弹性蛋白酶菌体生长;发酵产酶过程和基质消耗过程。并将3个动力学模型的预测值和实验值进行了比较,所建立的分批发酵动力学模型能较好地反映弹性蛋白酶分批发酵过程。     

界面发酵红曲霉的图像解析*

利用计算机视觉技术研究了红曲霉界面发酵过程中菌体形态变化与菌体生长的关系。在界面培养中通过检测前期菌落面积,后期隆起部分的表征体积——基于颜色变化的生长点分布,可以有效表示菌体生长状况。基于此建立了含有相应形态参数的动力学模型,该模型与常规动力学模型具有相似的表达形式。     

α-氯丙酸脱卤酶发酵动力学模型

对α-氯丙酸脱卤酶发酵动力学进行了研究。基于Logistic方程和Luedeking-Piret方程,得到了描述Pseudomonas W20菌发酵过程菌体生长、α-氯丙酸脱卤酶生成及基质消耗的动力学数学模型和模型参数,对试验数据与模型进行了验证比较,模型计算值与试验结果拟合良好,平均相对误差大部分小于10%;对脱卤酶反应动力学进行了研究,结果表明脱卤酶的脱卤反应基本符合米氏方程,并求得最大反应速率V_(max)=1.11×10~(-5)mol/(g·min),表观米氏常数K_m=3.72×10~(-3)mol/L。     

重组类人胶原蛋白工程菌补料发酵过程建模

对产类人胶原蛋白的重组大肠杆菌Escherichia coli(E. Coli) 的批式和分批-补料培养动力学进行了研究。通过检测发酵过程的基质浓度、菌体量和产物浓度,建立了一组反映发酵的动力学模型,并考虑了非工程菌存在的影响,分析了细胞生长、底物消耗、基因工程产物生成的过程,结果显示该动力学模型可以很好的拟合发酵过程。     

放射形土壤杆菌Q9415发酵产胞外多糖动力学研究

放射形土壤杆菌Q9415产胞外多糖PS-9415的发酵为混合型发酵。应用logistic方程和L-P方程对PS-9415发酵过程的菌体生长,多糖合成以及底物消耗的动力学进行了讨论。研究发现：logistic方程和L-P方程建立的动力学模型较好地拟合了实验数据。     

An investigation of non-steady-state algal growth. II. Mathematical modelling of co-nutrient-limited algal growth

The ability of mathematical models to simulate competition for nutrients between three algal species, the diatom Thalassiosira pseudonana, a marine raphidophyte Heterosigma carterae and the dinoflagellate Alexandrium minutum, was investigated. Transient growth models were parameterized and tested using a number of closely controlled laboratory data sets including batch monocultures, batch competition experiments and semi-continuous culture competition experiments. The cell quota model of algal growth was found to be adequate to simulate growth of both the raphidophyte and the dinoflagellate. Batch monoculture data for diatom growth obtained under either nitrogen (N) or silicon (Si) limitation could also be simulated with a quota-style model, which in this case included feedback inhibition of nutrient uptake. However, to simulate both batch and semi-continuous culture experiments (and competition between the species), it was necessary to consider diatom Si-N metabolism. A model was derived which contains a representation of both intracellular N ad Si, and of the interaction of these nutrients within the cell. The model used a co-nutrient limitation based on the perceived functional and structural role of N and Si, respectively, within the cell. Simulations indicated that models capable of adequately representing monoculture growth in batch culture may produce erroneous results when incorporated into models of competition. The co-nutrient model is a first step to producing tractable algal growth models which will represent multiple nutrient stress in transient growth conditions.      

法夫酵母分批发酵虾青素动力学研究

通过三联30L全自动发酵罐对虾青素产生菌法夫酵母的分批发酵动力学进行了研究,结果表明,法夫酵母的生长与限制性基质葡萄糖浓度之间符合Logistic方程,建立了细胞生长、产物合成和基质消耗随时间变化的数学模型。应用MATLAB软件对发酵动力学模型进行最优参数估计和非线性拟和,获得最大比生长速率（umax）和产物得率（Yp/x）分别为0.1829/h、0.1524g/g,虾青素分批发酵中细胞生长与产物合成属于偶联型,模型模拟计算结果和实验值能较好地吻合,动力学研究结果表明该模型能较好地反映细胞的生长、底物消耗和产物合成过程机制。     

姬松茸N516产活性多糖的发酵动力学研究

目的 :研究姬松茸产活性多糖的发酵动力学。方法 :以 5L发酵罐分批发酵和基于Logistic和Luedeking&Piret方程。结果 :菌体生长和胞内活性多糖生成是同步的 ;发酵液流变特性参数稠度系数 (K)先增后降 ,而流变特性指数 (n)先降后升。得到描述分批发酵过程的动力学数学模型和模型参数 ,同时对实验数据与模型参数进行了验证比较 ,模型计算与实验结果较好拟合。结论 :产活性多糖属于偶联型以及模型可用于预测发酵过程     

The influence of high substrate concentrations on microbial kinetics

High substrate concentrations inhibit growth and may distort the metabolism of microorganisms. Mechanisms causing substrate inhibition are discussed and used to derive several mathematical models representative of the entire concentration range, including stimulation of growth by low substrate concentrations. These kinetic models are tested with a variety of batch culture measurements of specific growth rate and respiration rate at widely-ranging substrate concentrations. Using one of the kinetic models, equations are developed for batch, continuous, and exponential-feed reactors. Comparison of results obtained in continuous culture with results from exponential-feed culture systems is shown to offer a novel experimental method for evaluating the effect of the cell age distribution on the properties and metabolic activity of a culture.     

Revisiting Verhulst and Monod models: analysis of batch and fed-batch cultures

The paper re-evaluates Verhulst and Monod models. It has been claimed that standard logistic equation cannot describe the decline phase of mammalian cells in batch and fed-batch cultures and in some cases it fails to fit somatic growth data. In the present work Verhulst, population-based mechanistic growth model was revisited to describe successfully viable cell density (VCD) in exponential and decline phases of batch and fed-batch cultures of three different CHO cell lines. Verhulst model constants, K, carrying capacity (VCD/ml or μg/ml) and r, intrinsic growth factor (h⁻¹) have physical meaning and they are of biological significance. These two parameters together define the course of growth and productivity and therefore, they are valuable in optimisation of culture media, developing feeding strategies and selection of cell lines for productivity. The Verhulst growth model approach was extended to develop productivity models for batch and fed-batch cultures. All Verhulst models were validated against blind data (R² > 0.95). Critical examination of theoretical approaches concluded that Monod parameters have no physical meaning. Monod-hybrid (pseudo-mechanistic) batch models were validated against specific growth rates of respective bolus and continuous fed-batch cultures (R² ≈ 0.90). The reduced form of Monod-hybrid model C_L/(K_L + C_L) describes specific growth rate during metabolic shift (R² ≈ 0.95). Verhulst substrate-based growth models compared favourably with Monod-hybrid models. Thus, experimental evidence implies that the constants in the Monod-hybrid model may not have physical meaning but they behave similarly to the biological constants in Michaelis–Menten enzyme kinetics, the basis of the Monod growth model.     

Exponential growth kinetics for Polyporus versicolor and Pleurotus ostreatus in submerged culture.

Simple mathematical models for a batch culture of pellet-forming fungi in submerged culture were tested on growth data for Polyporus versicolor (ATCC 12679) and Pleurotus ostreatus (ATCC 9415). A kinetic model based on a growth rate proportional to the two-thirds power of the cell mass was shown to be satisfactory. A model based on a growth rate directly proportional to the cell mass fitted the data equally well, however, and may be preferable because of mathematical simplicity.     

灵芝三萜酸分批发酵的非结构动力学模型

研究了灵芝胞内和胞外三萜酸在30L发酵罐中分批发酵的动力学特征。利用Sigmoid函数构建了灵芝细胞生长、底物消耗、胞内和胞外三萜酸的非结构动力学模型,并根据Boltzmann拟合求解出各模型参数。结果表明,各模型预测值能够较好地吻合实验实测值。灵芝细胞比生长速率在第2.5天达到最大值（μmax）,为0.700d?1;葡萄糖比消耗速率在第2.4天达到最大值（qS, max）为1.060d?1;胞内三萜酸比合成速率在第4.7天达到最大值（qITA, max）为11.345mg/(g·d);胞外三萜酸比合成速     

Exponential growth kinetics for Polyporus versicolor and Pleurotus ostreatus in submerged culture

Simple mathematical models for a batch culture of pellet-forming fungi in submerged culture were tested on growth data for Polyporus versicolor (ATCC 12679) and Pleurotus ostreatus (ATCC 9415). A kinetic model based on a growth rate proportional to the two-thirds power of the cell mass was shown to be satisfactory. A model based on a growth rate directly proportional to the cell mass fitted the data equally well, however, and may be preferable because of mathematical simplicity.     

Kinetics of pure cultures of hydrogen-oxidizing denitrifying bacteria and modeling of the interactions among them in mixed cultures

In this study we report the isolation of four denitrifying bacteria from a batch reactor, where the progress of hydrogenotrophic denitrification was examined. Only three of the strains had the ability to use hydrogen as electron donor. In the present work, kinetic batch experiments were carried out in order to study the dynamic characteristics of pure and defined mixed cultures of hydrogen-oxidizing denitrifying bacteria, under anoxic conditions, in a defined synthetic medium, in the presence of nitrates. Kinetic models were developed and the kinetic parameters were determined from the batch experiments for each bacterium separately. The behavior of mixed cultures and the interactions between the bacteria were described using kinetic models based on the kinetic models developed for each bacterium separately and their predictions were compared with the results from mixed culture experiments. The mathematical models that were developed and validated in the present work are capable of describing the behavior of the bacteria in pure and mixed cultures, and in particular, the kinetics of nitrate and nitrite reduction and cell growth.