流加补氨水代替碳酸钙在井冈霉素生物发酵中的研究

研究了井冈霉素生物发酵过程中,流加补氨水代替碳酸钙精确调控发酵pH值对发酵与提取的影响.结果表明,流加补氨水代替碳酸钙工艺可应用于井冈霉素发酵生产中,对井冈霉素发酵无不良影响,同时因消除了钙离子对膜分离浓缩的影响,保证了膜分离浓缩工艺的顺利实施,可提高提取收率6.8％.     

赤霉素GA4+7在5000L发酵罐中的中试发酵工艺

[目的]探索赤霉素GA4+7在5000 L发酵罐中的中试发酵工艺条件.[方法]赤霉素GA4+7发酵培养基配方和发酵条件的优化筛选研究,分别在摇瓶条件下和在5000 L发酵罐中进行,采用多因素不同水平的正交试验设计.赤霉素GA4+7发酵单位的检测采用HPLC法.[结果]获得了赤霉素GA4+7发酵培养基优化配方:淀粉+葡萄糖为9.0％+1.0％、花生粉+黄豆粉为1.2％+0.6％、磷酸二氢钾和硫酸铵为0.2％和0.01％;获得了赤霉素GA4+7在5000 L发酵罐中优化的发酵条件:温度32℃、发酵通气量V(空气)∶V(发酵液)为0.4∶1、种子罐接种摇瓶种液400 mL、种子罐培养液中硫酸铵含量为0.05％、发酵罐补糖、种子罐种龄和发酵移种量分别为38 h和12％、发酵罐中添加碳酸钙量为0.2％.[结论]成功地探索到赤霉素GA4+7在5000 L发酵罐中发酵工艺条件,GA4+7在5000 L发酵罐中发酵效价达到788 mg/L,且GA4/GA7比例为1.06,GA4+7产品质量好,该工艺条件为大罐发酵生产赤霉素GA4+7奠定了较坚实的基础.     

关键核网络及其在发酵过程在线建模中的应用

发酵过程通常采用流加补料操作,无稳态工作点、非线性强,且重要生物量往往无法在线测量。本文提出了一种适用于非线性多输入多输出的发酵过程在线建模方法：关键核网络（key kernel network,KKN）。结合过程的先验知识给出控制模型关键节点加入的准则,使其能自适应调整模型的复杂度,以提高建模的精度和速度,并给出了关键节点增加时KKN模型的在线递推形式。将KKN应用于青霉素发酵过程的在线建模,研究表明,KKN能同时快速、准确地预报菌体和产物浓度,且随着批次的增加,过程信息不断得到积累,模型精度逐渐提高。     

浅析膜分离技术在食品发酵工业中的应用

概述了膜分离技术。首先对膜技术进行了介绍,其次着重对不锈钢管式膜进行了介绍,包括管式膜的制作、特性等,进而分析了膜分离技术在食品发酵工业中的运用原理及与传统食品工业相比的优势。     

赖氨酸发酵动力学研究——流加方式优化

在４０Ｌ中试发酵罐上用优选菌株进行了Ｌ—赖氨酸分批流加发酵,用实验数据对文献报道的分批发酵动力学模型进行了验证。结果发现所有模型都不能很好的描述赖氨酸分批发酵过程动力学。最后,探讨了赖氨酸分批发酵的动力学机理,给出了流加优化方案。     

破乳剂在氨水焦油分离中的应用研究

氨水焦油分离效果直接影响焦油及循环氨水质量,本文对氨水焦油分离中使用破乳剂进行了探索,并通过静态试验及工业化试验研究了药剂的添加浓度对焦油、氨水质量的影响。     

高效破乳剂在焦油氨水分离中的研究与应用

分析了焦化厂焦油氨水分离系统的运行状况,筛选了高效破乳剂对焦油氨水进行分离试验。分离后焦油的含水量低于2.0%,焦油中的萘含量由8.9%升高到11.0%,提高了萘的回收率。     

VC二步发酵高糖流加工艺的研究

利用从生产中选育得到的耐高糖菌株,通过在线的检测数据,应用改进的高浓度山梨糖流加控制工艺,考察了初始山梨糖浓度、底物浓度、流加阶段pH等对维生素C二步发酵的影响,确定了适宜的控制工艺,提高了发酵水平及设备利用率.     

生物氮素在土霉素发酵生产中的应用

在土霉素发酵生产过程中,氮源的优劣起到了关键的作用,因此对于氮源的选择及优化,也就成了土霉素生产过程中的重要工作,本文针对生物氮素在土霉素发酵生产中的应用进行了研究。     

油茶粕脱茶皂素后的混菌发酵去毒工艺及饲养试验研究

从油茶粕中提取茶皂素后的固渣进行去毒处理和生物混菌发酵,获得饲养安全性高的饲料原料,部分替代价格高昂的玉米和大豆粕,并用获得的配合饲料对外三元肥猪及夏洛莱肉牛的饲养试验。从试验结果来分析,脱茶皂素后的油茶粕经过处理,能够显著改善25 kg左右小猪的生长速度,对肉牛的生长促进作用也很明显。     

壳聚糖/碳酸钙杂化膜的研究

通过壳聚糖/钙盐复合膜浸泡在Na2CO3水溶液的方法制备出了壳聚糖/碳酸钙杂化膜。用X射线衍射仪和扫描电子显微镜表征了杂化膜内碳酸钙的晶体结构和形貌。研究了杂化膜的力学性能、溶胀率、吸光度及热稳定性。结果表明:杂化膜内碳酸钙为长3.0μm,宽1.0μm的棒状晶体,以及直径为1.0~5.0μm的多层球形晶体。随着碳酸钙的质量分数从2.69%增加到4.20%,杂化膜的溶胀率从231.6%下降到149.5%,膜的吸光度也逐渐增加。当w(CaCO3)=3.12%时,杂化膜的拉伸强度达到最大值52.12 MPa。杂化膜的分解温度为315℃,高于壳聚糖膜的分解温度290℃。这种生物相容性好的杂化膜有望用作骨细胞培养的支架材料。     

Ag3PO4的制备及其复合材料研究进展

能源与环境已成为当前亟需解决的问题,半导体光催化技术因具有氧化降解有机污染物完全、不产生二次污染、易操作等优点,在环境治理和新能源开发领域成为热点研究课题之一。Ag3PO4因具有高量子效率、可见光响应及较高的光催化效率等特点而引起了广大研究者的关注,并具有广泛的应用前景。本文总结了Ag3PO4的制备方法、不同形貌Ag3PO4的可控合成及其复合材料的研究进展。     

pH值反馈控制赖氨酸补料发酵中的碳氮源补加方法

建立了一种基于发酵液pH信号反馈控制赖氨酸发酵中葡萄糖、氨和硫酸铵补加的方法,通过在不同碳源和氮源浓度下进行分批补料发酵,得到葡萄糖、氨和硫酸铵的质量消耗比为15.7:1:1.64. 按此比例配制三者的混合溶液,在补料开始后代替氨水调节pH,可在发酵过程中补加碳源和氮源. 结果表明,利用该补料方式可将葡萄糖浓度维持在8~16 g/L,铵离子浓度维持在1.52~3.38 g/L,可使赖氨酸最大浓度分别比恒基质浓度补料方式和间歇补料方式提高3.6%和17.2%,产酸率提高9.5%和28.8%,糖酸转化率提高4.9%和18.6%.     

Ammonium complex of niobium as a precursor for the preparation of Nb2O5/Al2O3 catalysts

Ammonium oxalate complex of niobium was investigated as an aqueous precursor for the preparation of x% Nb₂O₅/Al₂O₃ (x=5, 10, 20 and 30 wt.%) samples. Catalysts with the same Nb₂O₅ contents were also prepared from the traditional niobium oxalate/oxalic acid aqueous solution. The catalysts were characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), temperature-programmed reduction (TPR), infrared spectroscopy of chemisorbed pyridine and X-ray photoelectron spectroscopy (XPS). A comparison with the preparation method using the niobium oxalate salt was performed. The results showed that the niobium precursor influence the species growing leading to phases with different reducibility. The XPS revealed the presence of multilayers of niobium oxide on the Nb₂O₅/Al₂O₃ samples prepared by using niobium ammonium oxalate complex, while the ones obtained from niobium oxalate led to Nb₂O₅ particles islands. The addition of niobium oxide decreased the fraction of Lewis acid sites and increased the fraction of Brønsted acid sites, independent of the precursor salt. However, the creation of BAS was more pronounced on the Nb₂O₅/Al₂O₃ samples prepared from niobium oxalate.     

High pressure studies of alkali metal doped fullerides A4C60

The electrical resistance R of K₄C₆₀ and Li₄C₆₀ has been measured between 100 and 300 K under pressures up to 1 and 2 GPa, respectively. For both materials, the temperature coefficient of R is negative at all pressures and temperatures in this range. The transport properties of Li₄C₆₀ at low pressure are compatible with a recent observation of high ionic conductivity, but surprisingly, this conductivity term increases strongly with increasing pressure, contradicting an intuitive model. For K₄C₆₀ we see no sign of a recently suggested structural phase transformation at low temperature, nor can we find any convincing evidence for a lattice disproportionation as recently observed for Rb₄C₆₀.     

发酵与分离技术结合的过程及其在乙醇生产中的应用

本文系统地介绍了超滤、溶剂萃取、膜蒸馏、超滤及反渗透、渗透蒸发和渗透牵引等分离技术与发酵过程结合的基本原理，重点介绍了这些技术在乙醇发酵中的应用及新进展。与分离技术结合的乙醇发酵过程的开发，为提高生产率、降低生产成本开辟了一条新途径，是一种很有应用前景的乙醇生产方法。     

Cs0.86(NH4)1.14SO4Te(OH)6 in porous anodic alumina for micro fuel cell applications

Cs_0.86(NH₄)_1.14SO₄Te(OH)₆ supported by anodic alumina membranes (AAMs) has been characterized for the first time in H₂/O₂ fuel cell. The fabricated membrane electrode assemblies are able to produce peak power densities in the range 15–30 mW cm⁻² under mild conditions (room temperature, low humidity and low Pt loading) and show an increased durability with cycling with respect to previous results obtained with AAM-based fuel cell. The physico-chemical characterization of the electrolytes has been carried out through X-ray diffractometry, scanning electron microscopy and micro-raman analysis. An estimation of the composite membranes conductance under fuel cell operation has been carried out from I–V characteristics and EIS measurements at room temperature.     

A CO and CO2 tolerating (La0.9Ca0.1)2(Ni0.75Cu0.25)O4+d Ruddlesden-Popper membrane for oxygen separation

A series of novel dense mixed conducting ceramic membranes based on K₂NiF₄-type (La_1–xCa_x)₂ (Ni_0.75Cu_0.25)O_4+δ was successfully prepared through a sol-gel route. Their chemical compatibility, oxygen permeability, CO and CO₂ tolerance, and long-term CO₂ resistance regarding phase composition and crystal structure at different atmospheres were studied. The results show that higher Ca contents in the material lead to the formation of CaCO₃. A constant oxygen permeation flux of about 0.63 mL·min⁻¹·cm⁻² at 1173 K through a 0.65 mm thick membrane was measured for (La_0.9Ca_0.1)₂ (Ni_0.75Cu_0.25)O_4+δ, using either helium or pure CO₂ as sweep gas. Steady oxygen fluxes with no sign of deterioration of this membrane were observed with increasing CO₂ concentration. The membrane showed excellent chemical stability towards CO₂ for more than 1360 h and phase stability in presence of CO for 4 h at high temperature. In addition, this membrane did not deteriorate in a high-energy CO₂ plasma. The present work demonstrates that this (La_0.9Ca_0.1)₂(Ni_0.75Cu_0.25)O_4+δ membrane is a promising chemically robust candidate for oxygen separation applications.