2,3-丁二醇发酵液的双水相萃取

研究了从发酵液中双水相萃取2,3-丁二醇的工艺条件,以目标产物的分配系数和回收率为指标,分别考察了不同双水相萃取体系以及相组成对2,3-丁二醇分配的影响,确定了适合于2,3-丁二醇发酵液萃取的最佳相组成. 结果表明,适合2,3-丁二醇双水相萃取的体系为乙醇/硫酸铵体系,对于絮凝后的发酵液,采用硫酸铵浓度为20%(w)、乙醇浓度为27%(w)的双水相体系,发酵液中2,3-丁二醇的分配系数和回收率最高,分别达到了7.4和90.18%. 该工艺操作简单,能够有效地分离发酵液中的2,3-丁二醇.     

2,3-丁二醇的絮凝预处理研究

为使生物法制备2,3-丁二醇的后续分离纯化过程顺利进行,研究了絮凝法预处理2,3-丁二醇发酵液。选用10种絮凝剂,以絮凝率和蛋白去除率为指标,分别考察了絮凝剂、质量浓度、pH值、温度和搅拌时间等条件对2,3-丁二醇发酵液的絮凝效果、浓度及后续萃取过程的影响,得出较优絮凝条件:以氯化铁为絮凝剂,质量浓度为23 g/L,pH值5.1,温度为20—50℃,搅拌时间15 m in,静置20 m in。在此工艺条件下,2,3-丁二醇的絮凝率和蛋白去除率均可高达98%以上,为后续的分离纯化过程奠定基础。     

光催化合成2,3-二(4-吡啶基)-2,3-丁二醇的新方法

研究了2,3-二(4-吡啶基)-2,3-丁二醇的合成,以及Ti O2等催化剂在乙醇体系中和光催化条件下催化4-乙酰基吡啶合成2,3-二(4-吡啶基)-2,3-丁二醇的快慢。结果表明,在以乙醇为溶剂,Ti O2等催化剂存在下的氙光环境中,4-乙酰基吡啶能够在较短时间内偶联成2,3-二(4-吡啶基)-2,3-丁二醇。     

2,3-丁二醇发酵液的絮凝除菌与絮凝细胞的循环利用

研究了用壳聚糖/海藻酸钠复合絮凝剂处理2,3-丁二醇发酵液的工艺条件,以絮凝率为指标,考察了壳聚糖分子量、壳聚糖用量、海藻酸钠助凝剂用量、发酵液pH值、搅拌时间等因素对处理效果的影响,确定了适于2,3-丁二醇发酵液体系的絮凝工艺. 结果表明,最佳操作条件为壳聚糖分子量40 kDa,壳聚糖用量0.375 g/L,海藻酸钠助凝剂用量0.250 g/L,发酵液pH 5.0,搅拌时间30 min,静置1 h. 该条件下,絮凝率可达98%以上,2,3-丁二醇保留率约为99%,且絮凝后上清液清澈、透明. 絮凝后的菌体可再次利用,发酵过程中菌体最高浓度(OD值)可达13.5,其转化能力与絮凝前相当.     

发酵液中乳酸的盐析萃取

研究了一种利用盐析萃取法分离发酵液中乳酸的新方法. 通过系统考察乳酸在不同盐析萃取体系中的分配规律,发现K2HPO4-甲醇和K2HPO4-乙醇体系适合分离发酵液中的乳酸. 发酵液中乳酸浓度为167 g/L时,采用25%(w) K2HPO4-26%(w)甲醇盐析萃取体系,乳酸的分配系数和回收率分别为4.01和86.0%;采用14%(w) K2HPO4-30%(w)乙醇盐析萃取体系,乳酸的分配系数和回收率分别为3.23和90.6%. 此时上相中残余葡萄糖、菌体和可溶性蛋白的去除率分别达67.3%, 100%和85.9%.     

2,3-丁二醇分离提取工艺研究进展

2,3-丁二醇应用广泛,是一种潜在的平台化合物,可以用于替代传统平台化合物——四碳烃。基于能源安全及绿色环保的需求,生物炼制制备2,3-丁二醇受到人们的青睐。与化学法相比,生物炼制制备2,3-丁二醇具有明显的优势。然而,2,3-丁二醇的高沸点及强极性的特点使它难以从发酵液中分离。这成为了生物炼制2,3-丁二醇工艺工业化的瓶颈。因此,开发高效价廉的2,3-丁二醇分离工艺成为研究的重点。本文综述了从发酵液中分离2,3-丁二醇工艺的研究进展。2,3-丁二醇的分离主要包括固液分离、发酵液深处理及2,3-丁二醇精制3个方面,涉及的分离技术包括离心、絮凝、膜过滤、离子交换、电渗析、萃取、精馏等以及相关技术的优化和耦合。提出今后的研究重点在于现有分离工艺的高效整合及新型分离工艺的有效突破。     

两株Klebsiella pneumoniae菌发酵生产2,3-丁二醇的比较

对两株克雷伯氏菌(Klebsiella pneumoniae)批式流加发酵生产2,3-丁二醇进行了研究,结果表明,K. pneumoniae CICC 10011代谢产生的各种有机酸和乙醇浓度均明显低于K. pneumoniae DSM 2026,发酵56 h,目标产物(2,3-丁二醇+乙偶姻)浓度为85.61 g/L,生产强度为1.53 g/(L×h),葡萄糖质量转化率为45%. 对2株克雷伯氏菌发酵的代谢流量分析表明,K. pneumoniae CICC 10011是生产2,3-丁二醇的优良菌株.     

2,3-丁二醇分离纯化中反应精馏工艺

乙醛-环己烷反应萃取体系能够有效分离发酵液中的2,3-丁二醇。文章重点研究了2,3-丁二醇-乙醛反应萃取液的连续水解精馏工艺,为工业化生产提供理论基础。水解精馏使用阳离子交换树脂HZ732为水解催化剂,以2,4,5-三甲基-1,3-二氧戊环(2,3-丁二醇-乙醛缩醛)水解率为指标,考察了反应段温度、反应段级数、进料速度、进料油水比(2,4,5-三甲基-1,3-二氧戊环和水摩尔比)和回流比的影响。通过实验得到优化水解精馏工艺条件为:反应段平均温度90℃,反应段理论板数为20,进料油水比为0.6,进料速度0.2 h-1。在该条件下2,4,5-三甲基-1,3-二氧戊环水解率为73%,未水解2,4,5-三甲基-1,3-二氧戊环被回收。水解液经精馏得到2,3-丁二醇产品,纯度(质量分数)>96%,总收率≥93%。开发了连续水解精馏工艺,为整个工艺工业化实践提供了参考。     

2,3-丁二醇分离纯化中反应精馏的实验和模拟

对反应萃取-水解精馏法分离发酵液中2,3-丁二醇工艺中的水解精馏进行了实验和模拟研究。实验验证了4,5-二甲基-2-丙基-1,3-二氧戊环(DPD)水解精馏得到2,3-丁二醇的可行性。采用Aspen Plus建立反应精馏模型,以UNIFAC为热力学方程,RadFrac为反应精馏模块,对常压下DPD的水解精馏进行模拟,模拟结果与实验结果吻合较好。以2,3-丁二醇的收率为主要优化目标,考察最佳塔板数、进料位置、进料比、回流比和塔顶馏出比。模拟结果表明,在最佳操作条件下,塔釜2,3-丁二醇的收率为0.981,摩尔分率为0.150。     

高效液相色谱在葡萄糖加氢裂解中的应用

对于以葡萄糖为原料,在催化剂的作用下,通过加氢裂解得到含有1,2-丙二醇、乙二醇、2,3-丁二醇、1,2-丁二醇、1,4-丁二醇(以下简称二元醇)、山梨醇、丙三醇、甲酸盐、乙酸盐、乳酸盐以及其他未知物(以下简称重组份)的反应液,采用AminexHPX-87H Lon exclusion色谱柱,以0.006 mol/L的硫酸作为流动相,在流速0.5 mL/min的流量下,经示差折光化学检测器检测,能够将反应液中的二元醇以及重组份完全分离,且均在一定质量浓度范围内呈线性[1]。该方法分析反应液中的二元醇及重组份的回收率在97%～103%之间。本方法能够快速、精确测定反应液中二元醇与重组份的含量。     

1,2,4-丁三醇的双水相萃取

对低分子有机溶剂/无机盐双水相体系萃取分离发酵液中1,2,4-丁三醇（1,2,4-butanetriol，BT）进行了深入研究。通过对不同双水相体系的筛选，最终选定无水乙醇/K₂HPO₄双水相体系来萃取分离BT。使用浊点法对以BT为溶剂的无水乙醇/K₂HPO₄双水相体系进行相图的绘制，发现在K₂HPO₄质量分数为19.83%~46.87%范围内均能成相。通过单因素实验，考察双水相体系中无水乙醇/K₂HPO₄质量分数、pH对BT在两相之间分配系数和萃取效率的影响，得到最佳萃取条件为：系统总量10g、pH 9.5，无水乙醇/K₂HPO₄的质量分数为28%/28%，分配系数和萃取效率分别可以达到18.35和95.87%。在最佳萃取条件下，进一步探究了放大实验对体系萃取效率的影响，发现其对分配系数和萃取效率影响较小，体系稳定性高，为工业提取发酵液中BT提供新思路。     

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.     

盐析萃取菊芋发酵液中的2,3-丁二醇(英文)

The removal of solid impurities and separation of target products from a fermentation broth is becoming more tedious with the utilization of lignocelluloses as source of substrate.2,3-Butanediol,an important chemical used widely is also a main product of sugar-based fermentation carried out by Klebsiella pneumoniae.In this study,we investigated the use of salting-out extraction(SOE) that employed a K2HPO4/ethanol system consisting of 21% ethanol and 17% K2HPO4(mass fraction) to separate 2,3-butanediol from the viscous Jerusalem artichoke-based fermentation broth.After SOE,about 98% of solid matters was removed,and the viscosity decreased from 72.5 mPa s in the original fermentation broth to 4.4 mPa s in the top phase.The partition coefficient and yield of 2,3-butanediol reached 13.4 and 99%,respectively,and 89% of soluble proteins was removed from the broth.The results showed that SOE is an efficient way for isolating 2,3-BD from a highly viscous fermentation broth by removing much of the solid matters within the broth.     

Recovery and partial purification of thermophilic β-xylosidase derived from recombinant Bacillus megaterium MS941 by aqueous two-phase system

A polymer–salt-based aqueous two-phase system (ATPS) was developed for the effective extraction and purification of extracellular β-xylosidase from the fermentation broth of recombinant Bacillus megaterium MS941. The effect of molecular weight (MW) of polyethylene glycol (PEG), tie-line length (TLL), volume ratio (V_R), crude loading and pH on the recovery performance was evaluated. Under the optimal extraction conditions, β-xylosidase was successfully purified up to 23-fold with a recovery yield of 99% in the bottom salt-rich phase at PEG 4,000/potassium phosphate ATPS comprising TLL of 41.8, V_R of 2.3, crude loading (C_L) of 30% (w/w) at pH 6.     

PEG-(NH_4)_2SO_4双水相萃取法提取壳聚糖酶的研究

采用PEG-(NH4)2SO4双水相体系直接从Bacillussp.LS发酵液上清液中分离壳聚糖酶。研究了体系中PEG分子量、PEG质量分数、(NH4)2SO4质量分数、NaCl质量分数和pH值对壳聚糖酶分配系数及萃取率的影响。结果表明,室温下双水相萃取最佳条件为:PEG600 20%、(NH4)2SO420%、NaCl 0.1%、pH值6.0,在此条件下壳聚糖酶分配系数达5.91,萃取率达88.7%。     

Reactive extraction of 2,3-butanediol from fermentation broth

Biochemical 2,3-butanediol is a renewable material, but the lack of an effective separation process limits its industrial application. We developed an effective separation process to recover 2,3-butanediol from fermentation broth by reactive-extraction with ion-exchange resin HZ732 as catalyst. n-Butylaldehyde was used as both reactant and extractant. Feasible operation conditions were obtained as follows: room temperature, C _cat =200 g·L^?1, three-stage cross-current extraction, with reactant ratio (V _{Butylaldehyde} : V _{fermentation broth} ) 0.05 for each stage. Reactive-extraction can recover over 98% of 2,3-butanediol in the form of 2-propyl-4,5-dimethyl-1,3-dioxolane from fermentation broth. Then 2,3-butanediol was obtained by hydrolyzing 2-propyl-4,5-dimethyl-1,3-dioxolane and purified by vacuum distillation. The total yield rate of 2,3-butanediol through the process was over 94% and purity of final product reached 99%.     

Downstream processing of 1,3‐propanediol fermentation broth

The downstream processing of 1,3‐propanediol fermentation broth using flocculation, reactive extraction, and reactive distillation was studied. Cellular debris and soluble protein in the broth were flocculated by combined use of chitosan and polyacrylamide at optimal concentrations of 150 ppm and 70 ppm, respectively; the soluble protein in the broth decreased to 0.06 g L^?1, and the recovery ratio of the supernatant liquor to broth was greater than 99%. 1,3‐Propanediol and other alcohols were extracted from the supernatant liquor by reacting with butyraldehyde. In a four‐stage countercurrent extraction with the volume ratio of the extraction solvent to the aqueous phase being 20:100, more than 99% 1,3‐propanediol acetal (2‐propyl‐1,3‐dioxane) and 2,3‐butanediol acetal (2‐propyl‐4,5‐dimethyl‐1,3‐dioxolane) were recovered from the aqueous phase; 35% of the glycerol acetals were recovered. The acetals produced were hydrolyzed in a reactive distillation column using the strongly acidic cation‐exchange resin as catalyst, the bottom product obtained was a mixture of 1,3‐propanediol (407 g L^?1), 2,3‐butanediol (252 g L^?1), glycerol (277 g L^?1), and glycerol acetals (146 g L^?1). Copyright © 2005 Society of Chemical Industry     

Aqueous Two-Phase Extraction of Lactic Acid: Optimization by Response Surface Methodology

In this study a suitable alcohol/salt aqueous two-phase (ATP) system was selected for the recovery of lactic acid from an aqueous solution. From the different ATP systems studied, the ethanol/dipotassium hydrogen phosphate ATP system appeared to be favorable. To examine the potential of this ATP system, the extraction yield of lactic acid in aqueous solutions was optimized with the response surface methodology. The parameters studied were concentrations of ethanol (22.00–38.80%, w/w), dipotassium hydrogen phosphate (15.00–31.80%, w/w) and lactic acid (26.36–93.64 g/L). The optimum conditions were found to be 30.23% w/w ethanol, 18.40% w/w dipotassium hydrogen phosphate, and 80 g/L lactic acid. Under these conditions, a favorable extraction yield of lactic acid was obtained. The maximum partition coefficient of lactic acid and extraction yield was determined as 2.26 and 87%, respectively. The optimum extraction conditions were then used to guide the recovery of lactic acid from a real fermentation broth. As a result, the partition coefficient and extraction yield of lactic acid reached 2.06–80%, respectively.