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。     

地衣芽孢杆菌产生碱性蛋白酶的动力学研究

应用自动控制发酵设备,首先进行分批发酵试验摸索了地衣芽孢杆菌2709生长与代谢的基本规律。然后采用补料分批发酵方法限制生长基质浓度,测定了一系列(S_I,μ_I)、(μ_j,q_pj)数据,获得K_S、μ_max、α、β等参数的值,并且推导出了细胞生长与产物合成的动力学公式,从而证明了用Monod方程描述地衣芽孢杆菌2709生长速率与基质浓度关系的合理性和合成碱性蛋白酶的发酵属于生长部分关联型。     

Modeling and optimization of hairy root growth in fed‐batch process

This article proposes a feeding strategy based on a kinetic model to enhance hairy roots growth. A new approach for modeling hairy root growth is used, considering that there is no nutrient limitation thanks to an appropriate feeding, and the intracellular pools are supposed to be always saturated. Thus, the model describes the specific growth rate from extracellular concentration of the major nutrients and nutrient uptakes depend on biomass growth. An optimized feeding strategy was determined thanks to the model to maintain the major nutrient levels at their optimum assuming optimal initial concentrations. The optimal feed rate is computed in open loop using kinetic model prediction or in closed loop using conductivity measurements to estimate biomass growth. Datura innoxia was chosen as the model culture system. Shake flask cultures were used to calibrate the model. Finally, cultures in bioreactor were performed to validate the model and the control laws. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010     

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。     

灵芝胞外多糖分批发酵非结构动力学模型

在２Ｌ搅拌发酵罐上提出了描述了灵芝胞外多糖分批发酵过程中菌球生长、底物消耗和胞外多糖形成的非结构动力学模型。首先研究了灵芝分批发酵特性,结果表明该发酵过程属菌体生长和产物形成相偶联型。然后在总结文献的基础上,运用动力学模型,经过非线性回归,得到了模型中的参数值。通过计算机模拟,证明模型预测值与实际实验值具有良好的拟合性。     

溶氧及pH对产朊假丝酵母分批发酵生产谷胱甘肽的影响

在7 L发酵罐中研究了溶氧和pH对产朊假丝酵母分批发酵生产谷胱甘肽的影响。结果表明,当葡萄糖浓度为30 g/L且通气量控制在5 L/min时,搅拌转速达到300 r/min即可满足细胞生长和谷胱甘肽合成对溶解氧的需求。不同pH控制方式对谷胱甘肽分批发酵的影响有较大差异。不控制pH时,细胞干重和谷胱甘肽产量比控制pH为55的发酵分别低27%和95%,且有50%的谷胱甘肽向胞外渗漏。研究了将pH控制在4.0、4.5、5.0、5.5、6.0和6.5的谷胱甘肽分批发酵过程,发现在pH 5.5时谷胱甘肽总产量最高。用前期研究建立的动力学模型模拟了不同pH (4.0～6.5)下的分批发酵过程,并从动力学角度解释了pH对细胞生长和谷胱甘肽合成的影响。     

pH值对D-核糖发酵的影响及补料发酵的研究

研究了不同 pH值对D 核糖产量的影响。发酵初期pH自然下降时有利于菌体生长 ,菌体生长对数期较长 ,菌体质量浓度最高可达 15 .3g/L ;发酵中后期 pH值控制在 7.0时有利于D 核糖的持续合成 ,同时对D -核糖的流加补料发酵进行了初步研究 ,最终使菌体质量浓度最高达到 2 0 .1g/L ,D 核糖产量达到了 6 2 .5g/L。     

Infrared Spectra of Nitella Cell Walls and Orientation of Carboxylate Ions in the Walls

Infrared spectra of film specimens of the cell wall of Nitella were recorded in the untreated state, after acid treatment, and after treatment for removal of pectic substances and hemicellulose. Assignment of the bands in the spectrum of the wall was made. Polarization measurements on the wall indicate that in addition to cellulose, carboxylate ions, which are attributable to pectic substances, are oriented in the wall. The nature of the bonds holding the oriented carboxylate ions is described.     

Fed‐batch production of tetanus toxin by Clostridium tetani

This study deals with the effects of the initial nitrogen source (NZ Case TT) level and the protocol of glucose addition during the fed‐batch production of tetanus toxin by Clostridium tetani. An increase in the initial concentration of NZ Case TT (NZ₀) accelerated cell growth, increased the consumption of the nitrogen source as well as the final yield of tetanus toxin, which achieved the highest values (50–60 L_f/mL) for NZ₀ ≥ 50 g/L. The addition of glucose at fixed times (16, 56, and 88 h) ensured a toxin yield (～60 L_f/mL) about 33% higher than those of fed‐batch runs with addition at fixed concentration (～45 L_f/mL) and about 300% higher than those obtained in reference batch runs nowadays used at industrial scale. The results of this work promise to substantially improve the present production of tetanus toxin and may be adopted for human vaccine production after detoxification and purification. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010     

Effect of an exponential feeding regime on the production of Rhodotorula araucariae epoxide hydrolase in Yarrowia lipolytica

Aims: To evaluate the effect of and exponential feeding regime on the production of epoxide hydrolase (EH) enzyme in recombinant Yarrowia lipolytica in comparison to a constant feed strategy. Methods and Results: An exponential feed model was developed and fermentations were fed at six different exponential rates. A twofold increase in EH productivity and a 15% increase in volumetric EH activity was obtained by applying exponential glucose feed rates in fed‐batch cultivation. These responses were modelled to obtain a theoretical optimum feed rate that was validated in duplicate fermentations. The model optimum of 0·06 h^?1 resulted in a volumetric EH activity of c. 5500 U l^?1 h^?1 and a maximum activity of 206 000 U l^?1. This correlated well with model predictions, with a variance of <10%. Conclusions: The use of an exponential feed strategy at a rate of 0·06 h ^{? 1} yielded best results for all key responses which show a clear improvement over a constant feed strategy. Significance and Impact of the Study: The study was the first evaluation of an exponential feed strategy on recombinant Y. lipolytica for the production of EH enzyme. The results suggest a strategy for the commercial production of a valuable pharmaceutical enzyme.     

L-异亮氨酸分批发酵动力学模型的研究

对黄色短杆菌L－异亮氨酸高产菌XQ－4（AHV^rAEC^rSuc^gSG^rEth^rα－AB^rIleHx^r）分批发酵动力学模型进行了研究。建立了比较合理的L－异亮氨酸分批发酵动力学模型,为L－异亮氨酸补料分批发酵最优化的研究奠定基础。