发酵液中吩嗪-1-羧酸的初步分离工艺

通过考察吩嗪-1-羧酸(PCA)在不同pH值下的溶解度,利用PCA碱溶酸沉的性质,采用絮凝法去除发酵液中的大分子蛋白质和菌丝体等杂质,初步分离出代谢产物PCA;研究了絮凝剂用量、发酵液稀释倍数、pH值及温度对过滤速度、终产品PCA含量和回收率的影响. 结果表明,当以聚氯化铝为絮凝剂、发酵液稀释4倍、絮凝pH值为8.5、絮凝温度为30℃时,所得产品中PCA含量达69.9%,产品对发酵液的PCA回收率为91.3%.     

高黏发酵液中γ-聚谷氨酸的分离纯化工艺生物化工

γ-聚谷氨酸(γ-PGA)是由多种杆菌产生的一种胞外多肽,发酵生产时由于黏度高导致菌液分离困难。文中优化了发酵液微滤除菌、超滤浓缩和醇析干燥的工艺参数。综合考虑渗透通量、压差和除菌率等参数,确定微滤最佳操作温度为40℃,最佳操作压差0.3-0.4 MPa,最佳稀释度为V(发酵液)∶V(水)=1∶2,除菌率最高可达92.47%,在此条件下可以保持较高的渗透通量和较快的浓缩液循环流速,使微滤过程更为高效,同时不会因压力过高而造成微滤膜过早堵塞。通过优化,选择超滤最佳的浓缩比为5,此时渗透通量为31.8 L/(m2·h),产物回收率为81.6%。对pH=3—10共9个梯度进行了考察,比较在不同pH值条件下醇析操作纯化γ-PGA的粗产量,最优pH=7可达到最好的沉淀效果。这一优化分离工艺具有应用于γ-聚谷氨酸生产的潜力。     

发酵液中1,3-二羟基丙酮的分离提取研究

对氧化葡萄糖酸杆菌CGMCC1.23突变株GM51发酵得到的1,3-二羟基丙酮(DHA)发酵液,首先采用300mg?L?1天然高分子絮凝剂壳聚糖和3%(w/v)活性炭对DHA发酵液进行预处理,然后浓缩发酵液至含水量为10%～20%范围内,加入体积比为3:1的乙醇醇沉脱盐和蛋白杂质后,蒸发发酵液,于5℃大于90%乙醇水中结晶得到DHA产品。结果表明整个工艺过程中DHA产品的收率为72%,高效液相色谱检测DHA晶体纯度99%。本研究结果对发酵液中DHA大规模分离提取应用提供了可靠的基础。     

金银花中绿原酸的超滤纯化

采用超滤法纯化金银花提取液中的绿原酸.考察膜的截留相对分子质量、操作压力、原料液浓度以及pH等因素对超滤效果的影响,探讨膜通量的衰减规律,并将优化后的结果与醇沉法比较.结果表明：在考察的3种膜中,控制压力0.07MPa、pH3.5时截留相对分子质量50000的膜超滤效果最好.采用浓缩液回流的方式对原始浓度的提取液超滤后,浓缩液再稀释3次,继续稀释超滤,绿原酸的纯度为19.6%,是醇沉法的1.6倍,回收率为98.9%,比醇沉法高12.3%.     

应用膜分离技术改进林可霉素提炼工艺

介绍了在混合醇萃取前,引入超滤-纳滤组合膜分离技术对板框过滤后的林可霉素发酵液进行提纯和浓缩的小试结果：碱化料液的膜分离效果优于未碱化料液;对不同材料（PES、PS、PA）和相对截留分子质量的超滤和纳滤膜的筛选结果表明,PES-10和NF-270膜在膜通量和林可霉素收率、杂质去除等方面优于其他的膜,为最佳选择;超滤-纳滤后再进行萃取,不但混合醇的用量因料液体积减小而相应减少,并且萃取效率和产品收率都得到提高,当纳滤浓缩倍数为1.28时,一次萃取率和总收率分别比原来无超滤-纳滤时增加了4.3%和3.4%,所得萃取液的色度也较低.     

超滤和纳滤膜分离提取纳他霉素

为提高纳他霉素(natamycin)生产提取得率,减少溶剂使用,本文采用超滤、纳滤操作对工业生产的纳他霉索发酵液进行处理。实验结果表明:操作压力、操作时间及料液流速对超滤过程有很大影响。通过超滤可将蛋白质等大分子杂质去除,然后再用纳滤膜对超滤渗透液进行浓缩纯化,对纳滤工艺的操作条件如进料压力、料液pH、浓缩倍数等进行了研究。采用超滤、纳滤技术提取纳他霉素,其收率可达62.74%。     

中空纤维超滤膜去除乳酸钙中蛋白质的研究

发酵法联合生产乳酸-乳酸钙工艺中,分离出的乳酸钙产品含有蛋白质、还原糖、重金属等杂质,影响产品的品质。本实验研究了中空纤维膜对乳酸钙中蛋白质的去除,并分析了压差、温度、浓度及pH值等因素的影响。得到了较好的工艺操作条件为Δp=0.05MPa,Δ=30g/L,30°C,pH=4。进一步提出用多步超滤能提高蛋白质的去除率15%～27%。     

超滤技术在红花黄色素提取中的应用研究

常规醇沉法提取生产红花黄色素流程长,工艺复杂.本文从超滤对红花提取液中主要杂质(蛋白、鞣质、多糖)的截留作用,从红花黄色素提取率以及超滤过程的操作稳定性方面探讨了超滤技术在红花黄色素提取中应用的可行性.通过实验发现,选用截留值(1～3)×104的聚砜超滤膜对提取液中的蛋白、鞣质有较好的截留效果,对多糖的截留效果不明显,超滤纯化后的红花黄色素质量与提取率明显优于醇沉法.同时超滤时料液的浓度和温度对操作的稳定性有较大影响,但控制合适的温度和浓度可得到较长时间的稳定操作时间.     

浸没式超滤膜组合工艺处理饮用水的中试研究

通过中试实验研究了混凝沉淀-超滤、混凝沉淀-砂滤-超滤和混凝沉淀-升流式曝气生物活性炭-超滤三种工艺处理饮用水的净水效果及对膜污染影响情况。结果表明,3种工艺的浊度和颗粒数去除率均能达到99%以上且不受原水水质影响,都能去除水中大多数的微生物和浮游动物,说明超滤膜组合工艺能有效的保证出水的生物安全性。超滤膜本身对水中溶解性有机物和氨氮的去除效果较差,相对于混凝沉淀-超滤工艺,选用混凝沉淀-砂滤-超滤工艺和混凝沉淀-升流式曝气生物活性炭-超滤工艺对COD_(Mn)、UV_(254)及氨氮的去除率分别提高了21.2%、18.2%、28.6%和40.8%、63.7%、59.2%,且这两种工艺的过滤阻力也远小于混凝沉淀-超滤工艺的过滤阻力。     

灵芝菌丝体多糖的超滤提取及其抗氧化活性的研究

考察了超滤浓缩醇沉法提取发酵灵芝菌丝体多糖,与减压浓缩法相比,多糖含量、多糖得率均高于后者,所得多糖的品质得到提高,减轻了后续多糖纯化的负担。灵芝菌丝体粗多糖对羟自由基.OH(HFR)有较好的清除能力,在一定范围内清除率与多糖浓度呈正相关,超滤浓缩醇沉法提取灵芝菌丝多糖的.OH清除率高于减压浓缩醇沉法。     

Separation of 1,3-propanediol from glycerol-based fermentations of Klebsiella pneumoniae by alcohol precipitation and dilution crystallization

The separation of 1,3-propanediol from the glycerol-based fermentation broth of Klebsiella pneumoniae plays an important role during the microbial production of 1,3-propanediol. In this paper, the separation of 1,3-propanediol from fermentative broth by a combination of ultrafiltration and alcohol dilution crystallization was investigated. The broth was first filtered by ultrafiltration, and 99% of cells, 89.4% of proteins and 69% of nucleic acids were removed. The obtained broth was further condensed by vacuum distillation, and then alcohol was added. The macromolecular impurities, such as nucleic acids, polysaccharides and proteins, were precipitated, and inorganic and organic salts were crystallized. The optimal volume ratio of alcohol added to the condensed fermentation broth was determined to be 2:1. As a result, proteins, nucleic acids and electric conductivity decreased by 97.4%, 89.7% and 95.8%, respectively, compared with the fermentative broth. The influences of pH and water content in condensed broth on alcohol precipitation and dilution crystallization were also investigated. The experimental results indicated that alcohol precipitation and dilution crystallization was feasible and effective for the separation of 1,3-propanediol from actual fermentation broth. Translated from The Chinese Journal of Process Engineering, 2006, 6(3): 454–457 [译自: 过程工程学报]     

絮凝与膜超滤耦合预处理谷氨酰胺发酵液

采用絮凝与膜超滤相耦合的方法对谷氨酰胺发酵液进行预处理 ,详细讨论了壳聚糖做絮凝剂去除菌体和膜超滤去除蛋白和多糖等的效果及影响因素。实验表明 ,在壳聚糖质量浓度为80 0～ 10 0 0 g/m3 ,发酵液为 pH =4 0～ 6 0 ,温度 2 5℃左右 ,快速搅拌与慢速搅拌相结合的操作条件下 ,絮凝效果最佳 ,菌体去除率超过 95 %。采用截留相对分子质量为 6 0 0 0的中空纤维膜超滤絮凝后的谷氨酰胺发酵液 ,蛋白去除率 70 4 % ,总有机碳降低 5 7 3% ,大部分的蛋白和多糖被除掉。该预处理方法具有工业应用的前景     

The preparation of soy products with different levels of native phytate for zinc bioavailability studies

Soy products with low, intermediate and normal phytate levels were prepared in the pilot plant for subsequent rat-feeding experiments to evaluate zinc bioavailability. The low level (0.29%) phytate product was made by precipitation of the protein curd at pH 5.5, whereas the normal level (1.05%) phytate product was produced by a similar process except that the phytate previously isolated from the whey fraction was added back to the original curd as native phytate. The intermediate level (0.73%) phytate product was also produced by acid precipitation, but at pH 4.5. The pH 5.5 precipitation process yielded a large quantity of whey in which the ratio of water content to phytate was over 1,000 parts to 1. However, ca. 75% of the water was subsequently removed by reverse osmosis (RO), which increased the concentration of phytate in the whey fraction and facilitated its isolation. Protein was first removed from the whey by precipitation with trichloracetic acid, then phytate was precipitated in the supernatant with ferric chloride. Another series of experiments was run to find optimal conditions to convert ferric phytate to the more soluble sodium phytate form, using a minimal amount of sodium hydroxide so that the phytate could be recycled back to the curd without causing a large increase in sodium content of the product. There were only minor differences in the protein, lipid and mineral contents of the three products.     

Recovery and Functional Properties of Soy Storage Proteins from Lab- and Pilot-Plant Scale Oleosome Production

The aim of this study was to investigate soy protein recovery feasibility after lab- and pilot-plant scale oleosome isolation. The proteins were isolated by isoelectric precipitation and by ultrafiltration. The functional properties of the recovered proteins were compared to soy protein isolate produced in our laboratory. The residual lipid content in the aqueous supernatant affected the protein recovery yields and purities. Ethanol precipitation and ultrafiltration resulted in the best protein yields, which were 25 and 26% greater than protein yield obtained by isoelectric precipitation with distilled water dilution. The protein content of the isoelectric precipitated pilot-plant supernatant was higher (98%) than the protein content of ethanol-precipitated proteins (80%). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed similar peptide profiles for laboratory and pilot-plant supernatants. Protein solubility curves between pH 3 and 8 were typical for soy protein isolate with higher solubilities for proteins obtained from pilot-plant supernatant. The soy protein isolate and ethanol-precipitated protein had the highest emulsification capacity on a dry-weight basis. These desirable functional properties of proteins recovered as co-products after oleosome isolation suggest they are highly suitable for industrial application as food ingredients and their recovery would contribute to the economics of the overall oleosome fractionation process.     

Clarification of succinic acid fermentation broth by ultrafiltration in succinic acid bio–refinery

BACKGROUND: Succinic acid is an important precursor chemical for the synthesis of high value‐added products. In this work, ultrafiltration was first investigated to clarify succinic acid fermentation broth by integrating fermentation and separation and removal processes of the product in situ. Four different ultrafiltration membranes (PES 100 kDa, PES 30 kDa, PES 10 kDa and RC 10 kDa) were used in this work. RESULTS: Results indicate that ultrafiltration is feasible for clarifying succinic acid fermentation broth. Almost all the microorganism cells (99.6%) were removed from the fermentation broth. Proteins were also removed effectively by all the membranes studied. The removal rate was 79.86% for PES 100 kDa, 86.43% for PES 30 kDa, 86.83% for PES 10 kDa, and 80.06% for the RC 10 kDa. After ultrafiltration, a clearer permeate was obtained compared with that from centrifugation. CONCLUSION: Membranes operating at high flux are always susceptible to rapid fouling. Compared with molecular weight cut‐offs (MWCO), membrane material has a significant influence on the flux. Membrane flux measured in this study shows industrial potential of this technology in treatment of succinic acid fermentation broth. © 2012 Society of Chemical Industry     

过滤法分离纯化透明质酸

针对透明质酸的分离纯化,提出了用过滤法分离纯化透明质酸的工艺. 首先以20 g/L的溶解浓度将透明质酸粗品溶于去离子水中,并加入硅藻土作为吸附剂,调节溶液pH至4.6~4.8;然后采用硅藻土过滤、滤板过滤、超滤,用乙醇结晶后可得葡萄糖醛酸含量高达44.2%的透明质酸. 该工艺已成功应用于工业生产,所得产品的葡萄糖醛酸含量达47.3%,蛋白质含量为0.01%,相对分子量可达110万,收率高达90.5%.     

Effect of operating parameters on precipitation for recovery of lactic acid from calcium lactate fermentation broth

Precipitation is a simple, efficient method for separating and recovering lactic acid in the form of calcium lactate from fermentation broth by adding sulfuric acid. Major operating parameters of the recovery step as well as the temperature of concentration of the recovered lactic acid solution and the type and amount of adsorbent used for pigment (color) removal were optimized. When the molar ratio of calcium lactate to sulfuric acid was 1: 1 and the pH was increased to a value greater than the pKa (3.86), calcium sulfate was precipitated and could be removed more effectively, allowing for more efficient separation and recovery of supernatant lactic acid. Precipitation could be facilitated by adding calcium lactate solution with mixing (up to 220 rpm) and was completed in over 18 h. The optimal temperature for the concentration of lactic acid recovered from the supernatant after removing the precipitated calcium sulfate was found to be 90 °C in terms of the time required for concentration and the stability of the product. Activated carbon (SX-PLUS, 9 g/L) was most effective as an adsorbent for color removal from the recovered lactic acid. Under the optimized precipitation conditions, an overall yield of 92% of lactic acid from fermentation broth could be achieved.     

Purification of carbon dioxide produced during the fermentative production of fodder yeast and ethyl alcohol by saccharomyces cerevisiae

The impurities present in carbon dioxide produced during the fermentative production of fodder yeast and ethyl alcohol by Saccharomyces cerevisiae were mainly acetaldehyde and butyraldehyde. 2,4-DNP reagent was sensitive to these impurities and they were precipitated as hydrazones. The soluble volatile organic compounds were completely removed in washers (I and II). The other impurities present in carbon dioxide were removed by treating the gas with potassium permanganate and activated charcoal to obtain pure gas. The system used in the purification of carbon dioxide in the factory was efficient when washing water was sufficient (2400 litres of running water/h) and the potassium permanganate solution was changed when it was exhausted.     

Purification of carbon dioxide produced during the fermentative production of fodder yeast and ethyl alcohol by Saccharomyces cerevisiae

The impurities present in carbon dioxide produced during the fermentative production of fodder yeast and ethyl alcohol by Saccharomyces cerevisiae were mainly acetaldehyde and butyraldehyde. 2,4-DNP reagent was sensitive to these impurities and they were precipitated as hydrazones. The soluble volatile organic compounds were completely removed in washers (I and II). The other impurities present in carbon dioxide were removed by treating the gas with potassium permanganate and activated charcoal to obtain pure gas. The system used in the purification of carbon dioxide in the factory was efficient when washing water was sufficient (2400 litres of running water/h) and the potassium permanganate solution was changed when it was exhausted.