发酵液预处理工艺特性

研究了抗生素发酵液提取过程中的预处理工艺特性 ,考察了各种因素对过滤速度和滤液效价的影响 ,并以螺旋霉素 (SPM )为例进行了详细研究 .实验发现 ,SPM过滤滤液效价随过滤 pH值的不同而变化 ,在 pH =5 5时有一最佳峰值 .同时 ,在溶液中存在蛋白质的溶解平衡 ,在过酸过碱时蛋白质会变性沉淀 .而SPM在蛋白质沉淀等固形物上存在吸附平衡 ,许多外加物质可以产生竞争吸附而影响过滤收率 .对以上实验结果用修正的Langmuir吸附理论提出合理的解释 ,建立了理论模型 ,并推导出了数学公式 .     

西梭霉素发酵液预处理工艺特性

应用正交试验研究了絮凝剂类型、质量浓度、发酵液pH值、动态过滤等因素对西梭霉素发酵液预处理效果的影响,获得适宜的预处理工艺条件。实验结果表明阴离子型聚丙烯酰胺A8025质量浓度为0.14g/L、pH=9—10时絮凝效果较好,经絮凝处理后的发酵液死端过滤常数比未经絮凝处理的发酵液死端过滤常数提高27.8倍,在此基础上若采用动态过滤不仅能进一步提高过滤速率,而且在过滤过程中西梭霉素的损失减少了7.9%。     

基于预处理的水样检测结果分析

水样预处理过程中的不同处理方法或者说操作步骤对氨氮分析结果的影响有重要的影响,实验分析水样预处理方法对氨氮分析结果产生的影响,希望本实验的结果和分析能为实验操作人员提供一些有用的数据和经验,给广大实验操作者提供比较明确的数据和结论,以使操作人员能清晰判断要预处理与否并对水样进行合理的预处理操作。     

发酵液预处理过程的特性

本文对抗生素发酵下游提取过程中的预处理部分的工艺特性进行详细研究。以林可霉素为例考察对发酵液滤速和效价的各种影响因素。实验发现:林可霉素过滤滤液速度随过滤的pH值的不同而变,在pH值=2.8时有一最佳峰值;温度对林可霉素发酵液的也有一定的影响,过高或过低都会影响滤液的滤速,在一定范围内随着温度的升高而滤速加快,通过实验发现当温度在50～55℃时过滤速度最佳。在林可霉素滤液中可能存在着蛋白质的溶解平衡,在过酸过碱时蛋白质会变性沉淀,温度过高时也会造成蛋白质的沉淀。林可霉素在蛋白质沉淀等固形物上存在吸附平衡,从而会影响林可霉素的过滤收率。     

必特螺旋霉素萃取过程研究

从热力学角度考察了温度、pH值、NaH2PO4质量分数对不同溶剂体系中必特螺旋霉素溶解度的影响,研究了磷酸盐缓冲液萃取石油醚洗脱液中必特螺旋霉素过程工艺特性,详细考察了温度、pH值、NaH2PO4质量分数等诸因素对萃取过程分配系数α的影响。萃取实验选择H3PO4-质量分数0.7%NaH2PO4缓冲溶液为萃取剂,以A/O相比=1/10进行萃取。研究发现:萃取过程最佳pH值范围为2.0—2.2,萃取分配系数α随着温度的升高而变小,萃取过程为放热过程,低温与较高的NaH2PO4质量分数有利于萃取过程的进行。在实验基础上推导并建立了萃取分配系数α与pH值及温度T函数关系α-pH及α-T理论数学模型,并用Matlab软件拟合得到α-pH-T函数关系式。     

基于发酵液特性的透明质酸提取预处理工艺

为进一步提高透明质酸成品质量和提取收率,针对透明质酸发酵液中菌体和蛋白质的物化特性,采用25 g/L三氯乙酸灭活菌体并使蛋白质变性沉淀,以发酵液质量1.2%的混合硅藻土(粗细硅藻土比为1.5:1)为过滤助剂,过滤温度60℃,pH 7.0的发酵液预处理工艺提取透明质酸成品. 再配以酒精沉淀、气浮、酒精造粒的后处理工艺,所得成品透明质酸中葡萄糖醛酸含量达46.39%,蛋白质含量仅为0.047%,分子量为190万,提取收率为91.3%.     

发酵液絮凝过程絮凝体微尺度与分离性能

为探索发酵液絮凝分离过程规律以提高分离效率,本文在微观层面上研究发酵液絮凝过程中的剪切力、絮凝体尺度对絮凝体过滤分离效果的影响。以小诺霉素发酵液为研究对象,在絮凝过程中改变絮凝体所受的剪切力,使用激光粒度分析仪在0.02～2000 μm尺度内测定不同剪切力下絮凝体的粒度及粒度分布,并测定絮凝体的过滤速率及沉降速率。实验结果显示：絮凝体的粒度随剪切力的增大而减小,絮凝体的粒度分布宽度随剪切力的增大而增大;絮凝体的沉降分离速率随絮凝体粒度的增大而增大;在适度的剪切力下絮凝体有一适度的粒度及粒度分布宽度和较大的密实度,此时絮凝体的过滤分离速率有一最大值。实验结果表明：絮凝过程中的剪切力显著影响絮凝体的粒度、粒度分布和密实度,从而显著影响絮凝体的过滤速率及沉降速率。     

溶氧对生物转化螺旋霉素的影响

研究了溶氧对生米加链霉菌变株生物转化螺旋霉素的影响,确定这种生物转化反应是显著的需氧过程,发酵过程具有与一般抗生素发酵不同的两个摄氧率高峰．根据溶氧对菌体生长和转化反应的双重影响,初步建立了分阶段溶氧控制的发酵过程,终转化率提高了８％,并将发酵时间缩短了约１／６．     

青霉素发酵液中可溶性蛋白质的沉降及其在溶剂萃取中的乳化作用

利用自合成的阴离子型共聚物研究了青霉素发酵液中可溶性蛋白质的沉降行为．同时考察了发酵液中部分蛋白质被除去后,液液萃取过程中乳化程度的变化情况．实验结果表明,含反应性官能团的高分子共聚物能有效地除去青霉素发酵液中的蛋白质,减轻液液萃取过程中的乳化程度,从而提高青霉素的提取率,同时减少废渣的产生．高分子共聚物的组成对发酵液中蛋白质的沉降和有机相破乳有很大的影响．     

REMOVAL OF ETHANOL FROM CONTINUOUS FERMENTATION BROTH BY PERVAPORATION

In the process of continuous fermentation with pervaporation(PVAP),ethanol can be removed and concentrated simultaneously from the broth. In this work, two kinds of modified PDMS (polydimethylsiloxane) membranes used for PVAP have been tested, the characteristics and kinetics of the process were investigated, and a set of kinetic equations has been derived along with the experimental results. The results show some major advantages of this process over that with ultrafiltration, more concentrated ethanol can be obtained from the broth directly; no appreciable fouling on the membrane and the process can be controlled steadily.     

用四氢化萘预处理对煤快速热解的作用

研究了用四氢化萘预处理对煤快速热解的影响结果表明，须处理温度在200～250℃之间，总挥发份析出率达到最大值；压力从0．0MPa上升至4．5MPa总挥发份析出率呈线性上升；溶剂含量＜20Wt％时．总挥发份析出率随着它的增大而增大,对于所用四种媒，预处理都有增大总挥发份析出率之效果用色谱-质谱技术分析得到：预处理后，苯甲苯、二甲苯、三甲苯和苯乙烯都有所增加；苯酚、禁、茆、甲基苯并呋前增加较显著；脂键烃系列中C14和C15亦有显著增加     

被肌苷发酵液污染后的陶瓷膜再生方法研究

以工业化陶瓷膜来过滤肌苷发酵液，分析了膜的污染机理，求出了各分解阻力的百分率，并确定了处于主要地位的阻力。在此基础上，研究了清洗剂种类、浓度、温度、清洗时间及清洗方式对清洗效果的影响，所得到的结论对工业化生产有一定的指导意义。     

锌系工件的前处理设备和工艺管理

讨论了锌系工件喷淋式前处理、相关工艺、现场管理、技术参数、质量检验。介绍了安全与环保的相关注意事项。     

EFFECT OF PRETREATMENT CONDITIONS ON STRUCTURAL CHARACTERISTICS OF WHEAT STRAW

Structural characteristics of lignocellulosic biomass such as surface area, pore volume, crystallinity, hemicellulose, and lignin content significantly affect the yield of fermentable sugars for bioethanol production. In the present work, the effect of dilute acid pretreatment was studied on structural characteristics of wheat straw, using different combinations of process variables (temperature, time, and acid concentration). Pretreated wheat straw (PWS) exhibited higher available surface area and pore volume along with low hemicellulose and lignin content. Crystallinity index (CrI) of biomass at different pretreatment conditions showed an increased trend followed by sharp decrease at high temperature (190°C) conditions. Maximum increase in surface area (7.1 m²/g compared to 4.0 m²/g for untreated wheat straw) was obtained at pretreatment conditions of 180°C temperature, 0.5% (v/v) acid, and 7 min time. SEM imaging of biomass revealed that pore breaking, compression of pores, and partial pore blocking in the case of high temperature (190°C) pretreatment conditions may be the reason behind decreased surface area of biomass. FT-IR analysis showed almost complete hemicellulose removal and acid-soluble lignin removal after dilute acid pretreatment but insufficient removal of acid insoluble lignin.

[Supplementary material is available for this article. Go to the publisher's online edition of Chemical Engineering Communications for the following free supplemental resource: figure showing XRD pattern of biomass with respect to different pretreatment conditions.]     

用三烷基氧膦—煤油溶液从发酵滤液中萃取克拉维酸

报道了将中性磷这一高效萃取体系应用于克拉维酸的提取分离．研究了三烷基氧膦萃取克拉维酸的各种参数：ｐＨ、时间、相比、浓度等的影响，确定了最佳萃取条件及其工艺参数：３０％三烷基氧膦的煤油溶液为萃取剂，萃取平衡ｐＨ＝１．５，萃取相比Ｏ／Ａ＝１：３，并进行四级逆流萃取，饱和醋酸锂反萃，反萃平衡ｐＨ为７～７．５．     

EXTRACTION OF ACETOIN FROM FERMENTATION BROTH USING AN ACETONE/PHOSPHATE AQUEOUS TWO-PHASE SYSTEM

An aqueous two-phase system (ATPS) consisting of acetone and phosphate was used to extract acetoin from fermentation broth. The influence of phase composition on partition of acetoin was investigated. When the filtered fermentation broth was used, relatively high partition coefficient (22.3) and recovery coefficient (96.4%) of acetoin were obtained by a system composed of 30% (w/w) acetone and 35% (w/w) dipotassium hydrogen phosphate. Then the system was applied to extract unfiltered fermentation broth directly, and the recovery coefficient of acetoin was 94.3%. Simultaneously, the byproduct 2,3-butanediol could also be extracted with the recovery coefficient of 93.5%. In addition, the removal of residual sucrose, cells, proteins, and prodigiosin from the fermentation broth was studied, and the removal ratios of these impurities were all above 85%. Ultimately, the recovery of phosphate in the bottom phase was explored, and the recovery coefficient could reach 93.7% through pH adjustment and dilution crystallization. The recovered phosphate also showed good ATPS extraction ability. This method provides a new possible way for the separation of acetoin from fermentation broth.