α-蒎烯工程菌发酵动力学模型的建立

为了提高α-蒎烯产量,探索其发酵生产的规律,以α-蒎烯产生菌重组大肠杆菌YJM28为供试菌株,发酵周期24h作为发酵条件进行590 ml厌氧摇瓶发酵。最终采用基于Logistic和Luedeking-Piret等方程的供试菌株的菌体生长、产物合成以及底物消耗三个发酵动力学模型,最终确定菌体生长动力学模型为力学模型,说明上述三个模型能够较好的真实的描述供述菌株在在发酵过程中菌体生长、产物合成以及底物消耗的情况。     

梅特勒O2-Sensor溶氧电极在青霉素G发酵过程中的应用

青霉素G钾工业盐是氨苄青霉素及头孢类抗生素的原料药,青霉素发酵属单一纯菌种发酵,在发酵过程中,培养液中的溶解氧浓度CL高于菌体的C长临时,菌体的呼吸不受影响,青霉菌的各种代谢活动不受干扰;如果培养液中的CL低于菌体的C长临时,菌体的多种生化代谢就要受到影响,严重时会产生不可逆的抑制菌体生长和产物合成异常现象,所以溶解氧对生长菌的代谢过程及最终产物的生物合成起着绝定性的作用,详细阐述了梅特勒O2-Sensor溶氧电极在青霉素G发酵过程中的应用对青霉素发酵过程起着重要的指导意义。     

大伙房水库生态水质动力学模型研究

基于营养盐-浮游植物-碎屑（NPD）结构的生态系统模型,结合表征水体中有机物质浓度的生物化学碳化氧需求（CBOD）变化过程和溶解氧（DO）变化过程,建立了二维生态水质动力学模型。该模型包括了两个子模型,即水动力学子模型和生态系统动力学子模型。生态水质动力学模型的主体部分为有源项的对流扩散方程,生态系统动力学子模型即为该对流扩散方程的生态源项,为了求解生态水质动力学模型中的水动力因素,该模型耦合了二维水动力学子模型,应用有限差分法进行同步求解。     

基于系统动力学的产业技术路线图制定

将系统动力学引入产业技术路线图制定过程中,实施动态仿真,在界定系统边界的基础上,构建产业技术创新系统动力学模型,并给出主要系统动力学方程,旨在利用系统动力学定量、动态预测的特点对产业技术路线图的制定和更新提供参考和支持.     

旱地土壤氮素矿化的动力学研究

通过对有机质、全氮、Ｃ／Ｎ比差异较大的１０种土壤进行盆栽和培养试验，用对数方程、指数方程和幂函数方程对土壤氮素矿化过程进行模拟．结果表明：幂函数模型能很好地描述土壤Ｎ素矿化过程；建立了土壤氮素矿化的一级动力学模式，求出了不同模型中的参数；最后探讨了影响土壤氮素矿化动力学模型系数的土壤因子．     

制药发酵工艺技术分析

本文对制药发酵工艺技术进行综述。控制发酵过程的物理参数主要有温度、压力、搅拌转速、搅拌功率、空气流量、浊度等。控制发酵过程的化学参数主要有pH值、基质浓度、溶氧量、氧化还原电位等。控制发酵过程的生物参数主要有菌丝形态和菌体浓度。     

六自由度工业机械臂动力学建模及仿真

为了研究六自由度工业机械臂的动力学特性,基于拉格朗日方程建立机械臂的动力学理论和仿真模型。分别建立各个构件的转动动能、平动动能和势能方程,进而得到各个构件的拉格朗日因子,通过虚拟样机模型测量对应构件的拉格朗日因子三个组成部分,与相应的模型计算结果进行对比,验证拉格朗日因子的正确性。基于正确的拉格朗日因子和广义多刚体动力学方程,建立最终的机械臂动力学模型,并通过ADAMS动力学仿真验证所建立的模型的正确性。     

枯草芽孢杆菌菌株发酵生产工艺优化

本研究在枯草芽孢杆菌菌剂发酵通用培养基中添加了不同比例的豆饼粉和麸子粉,根据发酵过程中菌体数量的变化,对几种配方进行多次筛选试验,最终确定了通用培养基+1.5%豆饼粉+1.0%麸皮为最佳的枯草芽孢杆菌菌剂发酵培养基配方,即改良的培养基。     

不同磷源在抗生素发酵中的应用

磷是抗生素发酵培养基中的重要营养来源,对抗生素菌体生长和抗生素的合成有很大的影响。特别是在四环类抗生素发酵中,发酵液中磷浓度作为抗生素开始产生的限制性因素,对抗生素的起始合成量和最终的产生量有重大的关系。同时,相同磷浓度的发酵培养基中,不同种类的磷源构成对抗生素的产量有密切的关系。发酵培养基中磷的来源可以分为有机磷源和无机磷源,有机磷源主要是黄豆饼粉、玉米浆等,无机磷源主要是磷酸盐的化合物,如磷酸二氢钾、磷酸氢二钾等。本文讨论在发酵培养基中磷含量相同的情况下,两类不同的磷源对抗生素产量的影响,以及如何将两者进行合理配比解决一些生产问题。     

宇宙演化的真实感绘制

Millennium-2是目前规模最大的宇宙演化数值模拟项目.用光滑粒子动力学描述粒子对空间的影响,并用辐射传输方程构建光照模型,可绘制宇宙演化的真实感图像.由算法的能量合成保持线性形式的特点得到一种粒子并行的并行办法.将粒子足迹沿扫描线细分,可缓解程序分支扩散和粒度不均匀的问题,使该办法可以在CUDA平台上实现.测试数据证明本文的方法是有效的.     

餐厨垃圾发酵生物制氢研究进展

餐厨垃圾是城市生活垃圾的重要组成部分,其有机质含量十分丰富,容易被微生物利用.餐厨垃圾厌氧发酵生物制氢技术被认为是最有发展前景的废弃物资源化技术之一.本文综述了国内外餐厨垃圾发酵生物制氢的微生物学机理、工艺控制条件及动力学模型方面的研究进展,并提出将来餐厨垃圾发酵生物制氢研究的发展方向.     

Kinetic study and modeling of biosurfactant production using Bacillus sp.

BackgroundSurfactants are one of the most important raw materials used in various industrial fields as emulsifiers, corrosion inhibitors, foaming agents, detergent products, and so on. However, commercial surfactant production is costly, and its demand is steadily increasing. This study aimed to evaluate the performance of typical strains of Bacillus sp. to produce biosurfactants through fermentation. It also included the investigation of the effect of initial glucose concentration and the carbon to nitrogen ratio.ResultsThe biosurfactant yield was in the range of 1–2.46 g/L at initial glucose concentrations of 10–70 g/L. The optimum fermentation condition was achieved at a carbon to nitrogen ratio of 12.4, with a decrease in surface tension of up to 27 mN/m.ConclusionsFor further development and industrial applications, the modified Gompertz equation is proposed to predict the cell mass and biosurfactant production as a goodness of fit was obtained with this model. The modified Gompertz equation was also extended to enable the excellent prediction of the surface tension.     

Optimization of Bacillus subtilis cell growth effecting jiean-peptide production in fed batch fermentation using central composite design

BackgroundOptimization of nutrient feeding was developed to improve the growth of Bacillus subtilis in fed batch fermentation to increase the production of jiean-peptide (JAA). A central composite design (CCD) was used to obtain a model describing the relationship between glucose, total nitrogen, and the maximum cell dry weight in the culture broth with fed batch fermentation in a 5 L fermentor.ResultsThe results were analyzed using response surface methodology (RSM), and the optimized values of glucose and total nitrogen concentration were 30.70 g/L and 1.68 g/L in the culture, respectively. The highest cell dry weight was improved to 77.50 g/L in fed batch fermentation, which is 280% higher than the batch fermentation concentration (20.37 g/L). This led to a 44% increase of JAA production in fed batch fermentation as compared to the production of batch fermentation.ConclusionThe results of this work improve the present production of JAA and may be adopted for other objective products' production.     

玉米淀粉生料发酵酒精工艺条件的研究

玉米是黑龙江省的主要农作物之一,玉米的深加工利用是提高其产值的重要手段,本研究利用酶解玉米淀粉生料发酵生产酒精,对其发酵条件进行优化,得到玉米淀粉发酵酒精的最佳工艺条件:料水比1∶4、糖化酶加量为160u·g-1、发酵温度为34℃,干酵母加量为0.75%、pH为4.5、发酵时间6d,发酵酒精度为13.9%vol。     

Construction and application of a novel genetically engineered Aspergillus oryzae for expressing proteases

BackgroundWe aimed to test the possibility of improving polypeptide production from soybean meal fermentation by engineered Aspergillus oryzae strains. Four different protease genes were cloned and transformed into wild-type A. oryzae, and the engineered A. oryzae strains were then used for soybean meal fermentation.ResultsThe results showed different degrees of improvement in the protease activity of the four transformants when compared with wild-type A. oryzae. A major improvement in the polypeptide yield was achieved when these strains were used in soybean meal fermentation. The polypeptide conversion rate of one of the four transformants, A. oryzae pep, reached 35.9%, which was approximately twofold higher than that exhibited by wild-type A. oryzae. Amino acid content analysis showed that the essential amino acid content and amino acid composition of the fermentation product significantly improved when engineered A. oryzae strains were used for soybean meal fermentation.ConclusionsThese findings suggest that cloning of microbial protease genes with good physicochemical properties and expressing them in an ideal host such as A. oryzae is a novel strategy to enhance the value of soybean meal.     

微生物发酵生产十二碳二元酸的研究

热带假丝酵母（Candida tropicalis）是长碳链二元酸发酵生产中的常用菌种,而热带假丝酵母突变株HP-2-48是一株高产DC12的优良生产菌株。本文对十二碳二元酸的发酵进行了研究,考察了青霉素钠盐、尿素、丙烯酸、pH值对菌体生长、产酸的影响并对其作用机制进行了讨论,并据此建立了长碳链二元酸新的发酵工艺。     

利用木薯生产生物丁醇的技术研究

寻找可替代石油的燃料丁醇,利用分子生物学技术对丁醇梭菌进行改造,降低丁醇发酵法生产的成本,实现丁醇的大规模生产。     

极大螺旋藻藻蓝蛋白基因在巴斯德毕赤酵母X-33中表达的研究

通过PCR技术克隆了极大螺旋藻藻蓝蛋白基因，构建了克隆载体和表达载体，并将该基因导入巴斯德毕赤酵母X-33基因组，筛选了能够有效表达藻蓝蛋白基因的毕赤酵母工程菌株PC8，从而为发酵法生产藻蓝蛋白奠定了基础。     

Influencing factors on single-cell protein production by submerged fermentation: A review

Since more than twenty years ago, some species of bacteria and fungi have been used to produce protein biomass or single-cell protein (SCP), with inexpensive feedstock and wastes being used as their sources of carbon and energy. The role of SCP as a safe food and feed is being highlighted more because of the worldwide protein scarcity. Even though SCP has been successfully commercialized in the UK for decades, study of optimal fermentation conditions, various potential substrates, and a broad range of microorganisms is still being pursued by many researchers. In this article, commonly used methods for the production of SCP and different fermentation systems are briefly reviewed, with submerged fermentation being highlighted as a more commonly used method. Emphasis is given to the effect of influencing factors on the biomass yield and productivity in an effort to provide a comprehensive review for researchers in related fields of interest.How to cite: Reihani SFS, Khosravi-Darani K. Influencing factors on single cell protein production by submerged fermentation: A review. Electron J Biotechnol 2019;37. https://doi.org/10.1016/j.ejbt.2018.11.005.     

微生物法生产维生素K2(MK)

维生素K是一种重要的生理物质，在凝血和骨骼代谢中都有重要的作用，因此在医药等方面具有重要的应用．近年来国外有学者对以发酵法生产维生素K2作了研究．总结了国外以发酵法生产维生素K2的研究进展，并对维生素K2的提取及分析方法进行了探讨。