发酵液中乳酸的分离提取研究进展

乳酸是合成聚乳酸的原料,生物法制备乳酸是目前工业上生产乳酸的主要方法。但乳酸发酵液成分复杂,后续的分离提纯过程成了制约乳酸生产的技术瓶颈和难点,也决定着乳酸的品质与收率。本文对乳酸发酵液的主要的分离提取工艺进行了介绍,包括结晶分离技术、酯化水解法、萃取法、分子蒸馏法、膜分离法、吸附法及与发酵耦合的原位分离技术。并提出单一的分离技术很难有效提取乳酸,需将多种技术集成、改良提纯工艺路线。其中,将各种新型高效的集成技术与发酵过程的有机结合,实现连续或半连续的发酵过程,可提高乳酸产率和产品质量,有望形成高效率、高品质、低污染、低能耗、可工业化的乳酸提纯工艺路线。

发酵法长链二元酸分离提取研究进展

微生物发酵法生产长链二元酸(DC_n)具有良好的经济效益和环境效益,但由于发酵液组分复杂,使得DC_n的提取分离成为了制约生产的关键,同时也决定着产品的质量。综述了发酵法DC_n分离提取中的两种主要方法——水相法和溶剂法的研究进展。溶剂法提取工艺可满足下游高品质DC_n的工业生产要求,但存在能耗较高、生产线不稳定等问题。目前,利用水相法提取聚合级精产品的研究还处于实验室研发阶段,与其他分离提取工艺的联用是实现水相法提取DC_n精产品的研发重点。

发酵液中1,3-丙二醇分离提取的研究进展

1,3-丙二醇是合成聚乳酸的主要原料,以甘油为底物的生物法制备1,3-丙二醇是以绿色化学为特征的技术。但1,3-丙二醇极性很强、微生物发酵液成分较复杂,产品收率偏低,质量难符合制备高性能聚对苯二甲酸丙二醇酯的要求,故1,3-丙二醇的分离提纯成为了生物法合成技术的关键。对于1,3-丙二醇发酵液,提纯过程包括发酵液预处理、脱盐和浓缩提纯。本文讨论了用于1,3-丙二醇提纯的主要技术,包括采用离心、过滤、絮凝脱大分子物质,用离子交换、电渗析、双水相萃取或有机溶剂沉淀等方法脱盐类,及通过精馏、萃取、吸附对发酵液浓缩提纯,或是以上某几个分离工艺的组合。提出整个分离工艺仍存在很多问题,对各工艺路线不断进行优化,开发新的经济高效的分离提取工艺路线,是目前实现规模化生物法生产1,3-丙二醇的技术重点。

Group separation of coal components and new ideas of coal utilization as petroleum

Four different groups of components were separated from coal under mild conditions of extraction and stripping process. Within these groups, and with pre-separation, individual utilization of all coal components can be realized, similar to petroleum components and enhance the inherent value and utilization value of coal, as well as increase environmental benefits. The characteristics of each component were analyzed with measurements by FTIR, GC/MS, TEM and the establishment of caking properties. The results show that coal can be separated into residues, ultra-pure coal, asphaltene components and light components by adding solvents for stripping into the CS2/NMP mixed extraction solution. Those four groups of components present great differences in the presence of carbon and hydrogen elements, in the structure of functional groups, in their macroscopic structure and micro-morphology and caking properties. Every component possesses its own inherent values and approaches. A new idea of coal processes and utilization, similar to the use of petroleum is proposed.

基于小波消噪的EMD模型在GPS振动信号处理中的应用

经验模式分解和小波分解是当前有效处理非平稳信号的两种时频分析方法,它们各具有其优缺点,适用于不同的应用。从对GPS振动信号的预处理、时域和频域处理入手,结果分析表明,对GPS振动信号先进行小波滤波消除随机噪声的干扰,再应用经验模式分解更有利于变形特征信息的分离和提取,提取的信号与振动平台记录数据更加吻合。

Recent Advances in Separation of Bioactive Natural Products

Bioactive natural products are a main source of new drugs,functional foods and food additives.The separation of bioactive natural products plays an important role in transformation and use of biomass.The isolation and purification of bioactive principle from a complex matrix is often inherent bottleneck for the utilization of natural products,so a series of extraction and separation techniques have been developed.This review covers recent advances in the separation of bioactive natural products with an emphasis on their solubility and diffusion coefficients,recent extraction techniques and isolation techniques.This overview of recent technological advances,discussion of pertinent problems and prospect of current methodologies in the separation of bioactive natural products may provide a driving force for development of novel separation techniques.

Robust Blind Separation for MIMO Systems against Channel Mismatch Using Second-Order Cone Programming

To improve the deteriorated capacity gain and source recovery performance due to channel mismatch problem,this paper reports a research about blind separation method against channel mismatch in multiple-input multiple-output(MIMO) systems.The channel mismatch problem can be described as a channel with bounded fluctuant errors due to channel distortion or channel estimation errors.The problem of blind signal separation/extraction with channel mismatch is formulated as a cost function of blind source separation(BSS) subject to the second-order cone constraint,which can be called as second-order cone programing optimization problem.Then the resulting cost function is solved by approximate negentropy maximization using quasi-Newton iterative methods for blind separation/extraction source signals.Theoretical analysis demonstrates that the proposed algorithm has low computational complexity and improved performance advantages.Simulation results verify that the capacity gain and bit error rate(BER) performance of the proposed blind separation method is superior to those of the existing methods in MIMO systems with channel mismatch problem.

Isolation of refined solanesol from tobacco extracts by separation integrated technology

A separation integrated technology for isolating refined solanesol from tobacco extracts was provided. Some experimental installations applied in the separation integrated technology were designed. The experimental installations included saponification and extraction installation, cryogenic centrifugation crystallization installation and continuous midium pressure column chromatography separation installation In the paper, a separation integrated technology route was designed： saponification and extraction-crystallization - silica gel column chromatography-recrystallization. Finally, refined solanesol （-95.5%） was successfully got. The new method featured shorter experimental times, as well as lower solvent consumption, compared with the conventional extraction methods. So it showed great potential for efficient sample preparation and large-scale industrial application in the near future.

Isolation, cloning and sequencing of AFLP markers related to disease-resistance traits in Fenneropenaeus chinensis

Amplified fragment length polymorphisms (AFLP) technique was used to analyze the fingerprint- ing of four successive generations of Fenneropenaeus chinensis to reveal their disease-resistance traits. Some loci showed quite different genetic frequencies due to artificial selection, which implied that these fragments were putative markers related to the disease-resistance trait. We developed a simple and effective method to fur- ther characterize these AFLP fragments. Specific AFLP bands were cut directly from polyacrylamide gels, re-amplified, cloned and sequenced. Eight putative genetic markers were sequenced and their sizes ranged from 63 to 209 bp. The sequences were submitted to dbGSS (database of Genome Sequence Survey); and the BLAST analysis showed low similarity to the function genes, indicating these markers were tightly linked to a dis- ease-resistance trait but were not functional genes.

Isolation and Preparative Purification for Ginkgolides A and B

In this paper a simple preparative method for isolation and purification of ginkgolides A and B was developed,As starting material,a commercially available standardized ginkgo extract (EGb761,containing 24% flavonoid and 6% terpene trilactones) was used,After a pretreatment step,optimized by the uniform design method ,the concentrated intermediate extract with high content of GA and gb(+90%) was separated into the individual terpenes by preparative liquid chromatography eluted with petroleum ether-ethylacetate,Analysis of products was carried out by means of HPLC-ELSD(evaporative light -scattering detector),The results show that ginkgolides A and B are obtained in higher yield and better purity.

Isolation and Identification of Nicotiflorin and Narcissin from the Aerial Parts of Peucedanum aucheri Boiss.

Peucedanum aucheri Boiss. （Apiaceae） is a herbaceous wild plant native to Iran and is used in Iranian folk medicine as a diuretic and for the treatment of kidney disorders. Phytochemical investigation of different extracts prepared from the aerial part of P. aucheri Boiss. resulted to the isolation of two main flavonol glycosides from methanolic extract. Using comprehensive spectroscopic methods, including 1D and 2D nuclear magnetic resonance （NMR） spectroscopy and mass spectroscopy, chemical structure of isolated compounds were determined as kaempfrol-3-o-rutinoside （nicotiflorin） and isorhamnetin-3-o-rutinoside （narcissin）. Although narcissin has previously been isolated from P. ruthenicum, to the best of our knowledge, isolation of nicotiflorin from Peucedanum genus is reported for the first time.

Isolation,characterization and extraction of mer gene of Hg^(2+) resisting strain D_2

Mercury-resistant strain D2 was isolated from mercury-contaminated soil and investigations on its 16S rDNA sequence,growth,minimal inhibitory concentrations(MICs) of metals,antibiotic susceptibility and mer gene were conducted.The strain D2 can grow in the medium containing 60 mg/L mercury ion.It presents more than 99% identity of 16S rRNA gene with Pseudomonas aeruginosa,and exhibits high MIC values for heavy metals and a large spectrum antibiotics resistance.The mer RT gene sequence was amplified from chromosome.Strain D2 is identified as Pseudomonas aeruginosa and the resistance to mercuric ion is related to chromosome.

Study on Flavonoids and Triterpenoids Content of some Euphorbiaceae Plants

The Spurge family （Euphorbiaceae） is a large family of flowering plants. Two plant species of this family were collected from the Egyptian desert, extracted with methanol subjected to silica gel column chromatography to give six compounds, three compounds from each plant. The compounds isolated from the methanol extract of Euphorbia retusa Forssk were identified as kaempferol-3-beta-D glucopyranosyl （1）, 3-O-alpha-L-xylopyranosyl （1→3）-alpha-L xylopyranosyl （1→2）, beta-D glucopyranosyllup 1,12-diene-3,21-diol （2） and 5,7,8,3＇,4＇-pentahydroxy-3-methoxyflavone （3） and the compounds isolated from Euphorbia paralais L. identified as 3,5,3＇-trihydroxy-6,7-d-methoxy-4＇ （7＂-hydroxygeranyl-1＂-ether） flavones （4）, 3-O-syringic acid （1→4）-alpha-L- xylopyranosyl （1→3）, beta-D-rahminopyranosyl hederagenin （5） and 3-O-syringic acid （1→4）, beta-D-rahminopyranosyl （1→3）,beta-D-rahminopyranosyl hederagenin （6）. The structure of the isolated compounds was elucidated by chemical and spectrometric analysis such as Infera red （IR）, proton and carbon nuclear magnetic resonance （1H-, 13C-NMR） and chemical ionization mass spectrometry （CI-MS）.

Characterization of Glycerol-Extractable Organic Matter from Etna Soils of Different Ages

We characterized humic acids （HAs） and glycerol-extractable organic fractions （GEOFs） extracted from four Andisols, taken from comparable soil-climate conditions on the east side of Mount Etna. The soils were formed on old lava （about 9000 years ago）, old tephra （about 8 700 years ago）, recent lava （about 2 600 years ago） and recent tephra （about 3600 years ago）. A part of the organic matter of the soils, deprived of HAs and fulvic acids （FAs）, was isolated by glycerol extraction. The GEOF can not be extracted with alkaline solutions, probably because it is closely bound to the mineral component of the soil. The characterization of the extracted organic fraction was carried out using elementary and functional group analysis and Fourier transform infrared （FT-IR） spectroscopy. About 20 extractions were necessary to extract the HA and FA from the older soils and about 10 extractions to extract them from the younger soils. Data showed that the CEOFs had a greater ash content and a smaller N content, as well as a greater presence of aliphatic compounds and carboxylic groups as compared to the HA extracted from the same soil. The GEOFs extracted from younger soils also had a lower yield, ash and COOH-group content, and were more aliphatic than the GEOF extracted from older soils. Finally, the GEOFs were more closely bound to the amorphous component of the soil （＇short-range＇ minerals） and consequently less subject to biodegradation.

Liquid–liquid equilibrium extraction of ethanol with mixed solvent for bioethanol concentration

The extraction of ethanol with the solvents of aldehydes mixed with m-xylene was studied for the bioethanol concentration process.Furfural and benzaldehyde were selected as extraction solvents,with which the solubility of water is small,expecting large distribution coefficient of ethanol.The liquid–liquid two-phase region was the largest with m-xylene solvent,followed by benzaldehyde and furfural.The region of two liquid–liquid phase became larger with the mixed solvent of m-xylene and furfural than that with furfural solvent.The NRTL model was applied to the ethanol–water–furfural–m-xylene system,and the model could well express the liquid–liquid equilibrium of the system.For any solvent used in this study,the separation selectivity of ethanol relative to water decreased as the distribution coefficient of ethanol increased.The separation selectivity with m-xylene was the largest among the employed solvents,but the distribution coefficient was the smallest.The solvent mixture of furfural and m-xylene showed relatively high distribution coefficient of ethanol and separation selectivity,even in the higher mass fraction of m-xylene in the solvent phase.The ethanol extraction with a countercurrent multistage extractor by a continuous operation was simulated to evaluate the extraction performance.The ethanol content could be concentrated in the extract phase with relatively small number of extraction stages but low yield of ethanol was obtained.

Structures and Antiviral Activities of Butyrolactone Derivatives Isolated from Aspergillus terreus MXH-23

A new butyrolactone derivative,namely butyrolactone Ⅷ （1）,and six known butyrolactones （2-7） were separated from the ethyl acetate （EtOAc） extract of the fermentation broth of a fungus,Aspergillus terreus MXH-23.The chemical structures of these metabolites were identified by analyzing their nuclear magnetic resonance （NMR） and mass spectrometry （MS）.Known butyrolactone derivatives contain an α,β-unsaturated γ-lactone ring with α-hydroxyl and y-benzyl,and butyrolactone Ⅷ （1） was the first butyrolactones contains α-benzyl and γ-hydroxyl on α,β-unsaturated lactone ring.All of the butyrolactone derivatives were tested for their anti-influenza （H 1N 1） effects.Derivatives 4 and 7 showed moderate antiviral activities while the newly-identified,derivative 1,did not.

Extraction and Isolation of Type Ⅰ,Ⅲ and Ⅴ Collagens and Their SDS-PAGE Analyses

Type Ⅰ Ⅲ and Ⅴ collagens were extracted from bovine dermis and cornea by using pepsin treatment in acetic acid solution, followed by salt precipitation and dialysis, to purify and isolate each type of collagens. The preparation process was analyzed by using sodium dodecyl sulfate polyacrylamide gel electrophoresis （SDS-PAGE）. A reducing agent, 2-mercaptoethanol, was used to remove disulfide bonds and analyze the structure of the bonds involved between α chains in some types of collagens. The use of delayed reducing methods resulted in the difference between α1 （Ⅲ） and α1 （ Ⅰ ） chains in a mixture containing type Ⅰ and Ⅲ collagens. The structure of disulfide bonds among α chains exists potentially in type V collagen prepared from the pepsin-treatment extraction at 4 ℃, which differs from type Ⅲ collagen in relation to the locations of disulfide bonds. Compared with pepsin-treated collagen at 4 ℃, the relative molecular weights of α1 （V） and α2 （V） chains treated at room temperature decrease by 4.6% and 6.0%, respectively. It is concluded that type Ⅰ Ⅲ and Ⅴ collagens can be prepared from bovine dermis and cornea by the use of pepsin treatment, salt precipitation and dialysis. The interchain disulfide bonds lie potentially near the edges of termini of type V collagen molecules in extracellular matrix, and a small number of interchain crosslinks exist in type V collagen.

Purification and Biochemical Characterization of N-methyl-Histidylesterase from Camel （Camelus dromedarius） Liver

Camel Liver Esterase （LE） was isolated through five consecutive steps： Extraction with Tris/HCl buffer, pH 8, precipitation with ammonium sulfate, affinity chromatography on Affi-gel-butyric acid and on Affi-gel-oleic acid, and preparative polyacrylamide gel electrophoresis （PAGE）. The Km values were found as： methyl butyrate （8.3 mM）, α-naphthyl acetate （3.65 mM）, 13-naphthyl myristate （66.7 mM）, p-nitrophenyl acetate （0.29 mM）, and phenyl acetate （5.26 mM）. The Ki of LE inhibition by bis（4-nitrophenyl） phosphate was 7.9 p.M, and 58 μM by phenyl-methyl-sulfonyl fluoride. The inhibition by these inhibitors is irreversible. p-Hydroxymercuribenzoate or ethylenediamine-tetra-acetic acid did not inhibit the enzyme. LE showed a dimeric structure with molecular weight of 129 kD. The energy of activation of LE was 15.0, 5.5 and 10.75 Kcal, using the substrates： a-naphthyl acetate, p-nitrophenyl acetate, and methyl butyrate, respectively. The optimal pH for LE was between 8 and 10. The N-terminus was found as aspartic acid. The percentage of glycine residues （13.3%） was the highest whereas the percentage of cysteine residues （0.68%） was the lowest in LE. Amino acid composition shows that LE has -50% of its histidine residues as N-methylhistidines.

Isolation of Functional RNA from Heavily Infested, Wilted and Necrotic Leaf Tissues of Tea with High Polyphenol Content

A procedure is described to isolate intact RNA from tissues not previously undertaken-highly infested and wilted apical buds and leaves of tea [Camellia sinensis （L.） O. Ktze.]. The protocol uses a final concentration of 450 mM β mercaptoethanol （βME） and 10% Polyvinylpyrrolidone （PVP） to circumvent problems associated with large amounts of polyphenols, polysaccharides, pigments and other secondary metabolites not easily removed by conventional procedures. Furthermore, the proposed protocol is applicable to normal tissues and other plant tissues with similar stresses, containing compounds that interfere with RNA extractions. Total RNA could be used for downstream applications such as mRNA isolation, reverse transcription, quantitative Polymerase Chain Reaction （PCR）, cDNA library construction and Rapid amplification of cDNA ends （RACE）.

Endophytic Fungi Isolated from Mangrove （Rhyzopora mucronata） and Its Antibacterial Activity on Staphylococcus aureus and Escherichia coli

Disc diffusion method was used to investigate the antibacterial activity of methanol extract of five endophytic fungi isolated from mangrove （Rhizopora mucronata） on Staphylococcus aureus ATCC 9144 and Escherichia coli ATCC 8739, Fungi were isolated from leaf, stem and root of R. mucronata. Potato dextrose agar and potato dextrose broth were used for fungi purification and fermentation. Fungal metabolites were extracted with methanol （1 ： 1 v/v） for 24 h before vacuum evaporated to yield the crude extracts. Antimicrobial activity test was done according to the Kirby-Bauer test. The inhibition zone around each disc was considered to measure antibacterial activity of endophytic fungi. Only three endophytic fungi showed inhibition activity on S. aureus ATCC 9144 and two endophytic fungi showed inhibition on E. coil ATCC 8739. The results suggested that the extracts have a high potential for enteric diseases treatment caused by foodbome pathogen.