泡菜水中产生物表面活性剂酵母菌株的筛选

[背景]由微生物产生的生物表面活性剂(biosurfactant,BS)具有低毒性、高效性、生物可降解性等多种特性,能在一定程度上缓解化学表面活性剂所造成的环境问题,因此筛选高产、安全的BS生产菌株备受研究者的关注.[目的]从泡菜水中筛选能代谢合成药食两用型BS的微生物菌株.[方法]运用滴崩法和排油圈法从传统发酵食品泡...     

Production of Surfactants by Rhodococcus erythropolis Strain EK-1, Grown on Hydrophilic and Hydrophobic Substrates

The ability of Rhodococcus erythropolis strain EK-1 to produce surfactants when grown on hydrophilic (ethanol and glucose) and hydrophobic (liquid paraffins and hexadecane) substrates was studied. The strain was found to produce surfactants with emulsifying and surface-active properties. The production of surfactants depended on the composition of the nutritive medium, nature and concentration of the sources of carbon and nitrogen, and duration of cultivation. Chemically, surfactants produced by Rhodococcus erythropolis EK-1 grown on ethanol are a complex of lipids with polysaccharide–proteinaceous substances. The lipids include glycolipids (trehalose mono- and dicorynomycolates) and common lipids (cetyl alcohol, palmitic acid, methyl n-pentadecanoate, triglycerides, and mycolic acids).     

Invertase Proteinaceous Inhibitor of Cyphomandra Betacea Sendt Fruits

Abstract

This work describes a new invertase proteinaceous inhibitor from Cyphomandra hetacea Sendt. (tomate de árbol) fruits. The proteinaceous inhibitor was isolated and purified from a cell wall preparation. The pH stability, kinetics of the inhibition of the C. betacea invertase, inhibition of several higher plant invertases and lectin nature of the inhibitor were studied. The inhibitor structure involves a single polypeptide (Mr = 19000), as shown by gel filtration and SDS-PAGE determinations. N-terminal aminoacid sequence was determined. The properties and some structural features of the inhibitor are compared with the proteinaceous inhibitors from several plant species (Beta vulgaris L., Ipomoea batatas L. and Lycopersicon esculentum Mill.). All these inhibitors share lectinic properties, some common epitopes, some aminoacid sequences and a certain lack of specificity towards invertases of different species, genera and even plant family. In consequence, the inhibitors appear to belong to the same lectin family. It is now known that some lectins are part of the defence mechanism of higher plants against fungi and bacteria and this is a probable role of the proteinaceous inhibitors.     

Behavioural and Electroantennogram Responses of Male Cigarette Beetle (Lasioderma serricorne F.) to Optically Active Serricornins

Pievious work with MAPI, a serine protease inhibitor, has shown that inactivation of membrane bound protease by MAPI resulted in inhibition of normal sporulation of Bacillus subtilis IFO 3027 [Shimizu et al, Agric. Biol. Chem., 48, 365 (1984)]. In the cells cultured with MAPI, the cellular amount of IP-I, a cytoplasmic serine protease which is sensitive to EDTA was lower than the control cells. An endogenous proteinaceous inhibitor having specific inhibitory activity against IP-I was produced during the sporulation and its amount in the MAPI-treated cells was higher than that of control cells. The proteinaceous inhibitor was inactivated only by membrane bound protease. Consequently, IP-I was activated through degradation of proteinaceous inhibitor by membrane bound protease. It seems probable that the proteinaceous inhibitor and membrane bound protease are involved in the regulation of a protease system in sporulating cells of B. subtilis.     

Removal of nonionic surfactants from wastewater using a constructed wetland

Removal of nonionic surfactants from municipal wastewater using a constructed wetland with a horizontal subsurface flow was studied in 2009 and 2010. Extraction spectrophotometry with 3′,3″,5′,5″‐tetrabromophenolphthalein ethyl ester and KCl served to determine the analyte concentrations. Triton^® X‐100 was used as a standard to express the nonionic‐surfactant concentrations. Anionic and cationic surfactants were shown not to interfere during the determination. Nonionic surfactants were degraded (to products undeterminable by the method) with a high average efficiency that reached 98.1% in 2009 and 99.1% in 2010, respectively. The average concentration of nonionic surfactants at the inflow was 0.978 mg/l, while it was close to the limit of quantification at the outflow (0.014 mg/l). A significant fraction of nonionic surfactants (38.7%) was already degraded during the pretreatment, and only 14.0% of the nonionic surfactants remained in the interstitial H₂O taken in the vegetation bed at a distance of 1 m from the inflow zone at a 50‐cm depth. Nonionic surfactants were degraded both under aerobic and anaerobic conditions.     

Emulsification and degradation of "Bunker C" fuel oil by microorganisms

An enrichment culture procedure has been used to isolate mixed culture systems which grow upon “Bunker C” fuel oil. When inoculated into a mineral salts aqueous medium containing Bunker C oil, the mixed cultures initiate oil emulsification. Emulsification usually is observed in 24–48 hr. The role of microbes in this emulsification will be discussed. It appears that certain metabolic products produced by the microbe possess properties of surfactants. Bacteria and fungi have been isolated which possess the ability to cause emulsification. Freeze-dried biomass is also capable of emulsifying oil. Chromatographic analyses of biodegraded Bunker C fuel oil show that microorganisms selectively metabolize the n-paraffin fraction.     

In Situ emulsification and mobilization of gasoline range hydrocarbons using surfactants

In this article the conditions that govern surfactant‐enhanced emulsification and mobilization of petroleum hydrocarbons in soil are reviewed. The effect of soil properties, groundwater constituents, and differing surfactant solutions on the emulsification process is discussed. A constant head soil flushing apparatus used to characterize surfactant‐enhanced mobilization of m‐xylene is described. Data showing the effect of surfactant‐enhanced mobilization on m‐xylene removal efficiency in washed sand is presented. Flushing solutions were used at concentrations from below to well above the critical micelle concentration (CMC) of the surfactants used. Removal efficiencies are shown to vary with surfactant concentration and with surfactant type. Flushing solutions of anionic, nonionic, and anionic/nonionic surfactant mixtures were evaluated.     

Enzymatic Modification of Protein Functionality: Implantation of Potent Amphiphilicity to Succinylated Proteins by Covalent Attachment of Leucine Alkyl Esters

This work is a new attempt to modify the functionality of food proteins by the use of a potential activity of papain. Fish protein concentrate, soy protein isolate, casein, ovalbumin and gelatin were succinylated prior to using them as substrates. Each of the L-leucine n-alkyl esters with different alkyl-chain lengths was covalently incorporated into each substrate by applying the unusual papain-catalyzed reaction [Agric. Biol. Chem., 43, 1065 (1979)]. The resulting products posessed high whippability and/or emulsifying activity. The highest whippability was observed when leucine butyl ester or hexyl ester was incorporated, while the incorporation of higher alkyl esters generally caused an increase in emulsifying activity.     

Phase Behaviour and Formation of Fatty Acid Esters Nanoemulsions Containing Piroxicam

Fatty acid esters are long-chain esters, produced from the reaction of fatty acids and alcohols. They possess potential applications in cosmetic and pharmaceutical formulations due to their excellent wetting behaviour at interfaces and a non-greasy feeling when applied on the skin surfaces. This preliminary work was carried out to construct pseudo-ternary phase diagrams for oleyl laurate, oleyl stearate and oleyl oleate with surfactants and piroxicam. Then, the preparation and optimization study via ‘One-At-A-Time Approach’ were carried out to determine the optimum amount of oil, surfactants and stabilizer using low-energy emulsification method. The results revealed that multi-phase region dominated the three pseudo-ternary phase diagrams. A composition was chosen from each multi-phase region for preparing the nanoemulsions systems containing piroxicam by incorporating a hydrocolloid stabilizer. The results showed that the optimum amount (w/w) of oil for oleyl laurate nanoemulsions was 30 and 20 g (w/w) for oleyl stearate nanoemulsions and oleyl oleate nanoemulsions. For each nanoemulsions system, the amount of mixed surfactants and stabilizer needed for the emulsification to take place was found to be 10 and 0.5 g (w/w), respectively. The emulsification process via high-energy emulsification method successfully produced nano-sized range particles. The nanoemulsions systems passed the centrifugation test and freeze–thaw cycle with no phase failures, and stable for 3 months at various storage temperatures (3°C, 25°C and 45°C). The results proved that the prepared nanoemulsions system cannot be formed spontaneously, and thus, energy input was required to produce nano-sized range particles.     

Effects of biosurfactants produced by Candida antarctica on the biodegradation of petroleum compounds

The effects of biosurfactants on the biodegradation of petroleum compounds were investigated. Candida antarctica T-34 could produce extracellular biosurfactant mannosylerythritol lipids (MELs) when it was cultured in vegetable oil. In addition, in our previous study, it was found that this strain could also produce a new type of biosurfactant while it grew on n-undecane (C₁₁H₂₄), and the biosurfactant was named as BS-UC. In flask culture of Candida antarctica, the addition of BS-UC could improve the biodegradation rate of some n-alkanes (e.g. 90.2% for n-decane, 90.2% for n-undecane, 89.0% for dodecane), a mixture of n-alkanes (82.3%) and kerosene (72.5%). By comparing the effects of the biosurfactants BS-UC and MEL and chemical surfactants on the biodegradation of crude oil, it was found that biosurfactants could be used to enhance the degradation of petroleum compounds instead of chemical surfactants. In a laboratory scale immobilized bioreactor, the addition of biosurfactant improved not only the emulsification of kerosene in simulated wastewater but also its biodegradation rate. The highest degradation rate of kerosene by addition of MEL and BS-UC reached 87 and 90% at 15 h, respectively. The results showed that the biosurfactant BS-UC was highly promising for work on biodegradation of hydrophobic contaminants.     

Resolution of N-(2-ethyl-6-methylphenyl) alanine catalyzed by Lipase B from Candida antarctica

A biotransformation process has been developed for the production of (S)-N-(2-ethyl-6-methylphenyl) alanine by enantioselective hydrolysis of racemic methyl ester in the presence of Candida antarctica lipase B (CAL-B). However, the enantioselectivity of CAL-B towards the resolution is not high enough to obtain enantiomerically pure product. In order to improve the enantioselectivity of the enzyme, the effects of surfactants on CAL-B-catalyzed hydrolysis were tested. The results suggest that surfactants can influence the microenvironment of the enzyme, and the addition of Tween-80, in particular, to the reaction medium markedly enhanced the selectivity of CAL-B towards the substrate used, with the enantiomeric ratio (E-value) increasing from 11.3 to 60.1.     

Lipases catalyzed enantioselective hydrolysis of (R,S)-methyl 1,4-benzodioxan-2-carboxylate intermediate for (S)-doxazosin mesylate

(S)-1,4-benzodioxan-2-carboxylic acid-1 is used as starting compound for the production of the more effective (S) enantiomer of the drug doxazosin mesylate. The catalytic ability of some commercial lipases for preparations of (S) enantiomer of 1 from (±) methyl 1,4-benzodioxin-2-carboxylate-2 is reported. Lipases from bacterial sources were more successful in resolving the ester than those from the yeast lipases. About 85% enantiomerically pure ester was achieved by lipase from alcaligenes sp.     

Furanoditerpenes from Arcangelisia flava (L.) Merr. and their antifungal activity

Two furanoditerpenes, 2α,3α-epoxy-2,3,7,8α-tetrahydropenianthic acid methyl ester (1) and 2α,3α-epoxy-2,3-dihydropenianthic acid methyl ester (2) were isolated and identified from the root of Arcangelisia flava (L.) Merr. The configuration of 1 was determined by X-ray crystallographic analysis and two-dimensional NMR. Fibraurin (3), fibleucin (4), 2β, 3α-dihydroxy-2,3,7,8α-tetrahydropenianthic acid-2,17-lactone (5), p-hydroxybenzaldehyde and vanillin were also isolated and identified by NMR and EI-MS or FAB-MS. The 2β, 3α-dihydroxy-2,3,7,8α-tetrahydropenianthic acid-2,17-lactone (5) showed the highest antifungal activity of the isolated five furanoditerpenes against a white-rot fungus (Trametes versicolor) and a brown-rot fungus (Fomitopsis palustris).     

Encapsulation of Lipophilic Bioactive Molecules by Microchannel Emulsification

Currently, much effort is being invested in novel formulations of bioactive molecules, such as emulsions, for pharmaceutical, food, and cosmetic applications. Therefore, methods to produce emulsions with controlled-size droplets of uniform size distribution have been developed. On this concern, a microfluidic device called the microchannel (MC) was used in this work for emulsification. This is a novel method for producing monodispersed emulsion droplets with very narrow droplet size distribution and low energy input, due to the spontaneous droplet generation basically driven by the interfacial tension, unlike other conventional emulsification processes. This technology provides the formulation of oil-in-water (O/W) emulsions containing lipophilic active molecules with increased bioavailability, which may be readily absorbed by the human body. MC emulsification enables the preparation of highly monodispersed O/W emulsions, which may be applied as enhancer on active molecules delivery systems, as well as in foodstuff. In this study, formulations of O/W emulsions loaded with bioactive molecules, such as β-carotene and γ-oryzanol, were prepared by the MC emulsification process. Refined soybean oil containing the dissolved lipophilic molecule and either sugar ester or gelatin solution (1 wt.%) were used as the dispersed and continuous phases, respectively. The emulsification process conducted using the asymmetric straight-through MC plate enabled the production of monodispersed O/W emulsions, resulting in β-carotene-loaded O/W emulsions with average droplet size (d _av) of 27.6 μm and coefficient of variation (CV) of 2.3% and γ-oryzanol-loaded droplets with d _av of 28.8 μm and CV of 3.8%. The highly monodisperse β-carotene-loaded droplets were physically stable throughout the storage period observed, resulting in droplets with d _av 28.2 μm and CV of 2.9% after 4 months storage in darkness at 5 °C. Single micrometer-sized monodisperse emulsions loaded with β-carotene were successfully formulated using the grooved MC emulsification, resulting in droplets with d _av of 9.1 μm and CV of 6.2%. This work was funded by The Ministry of Agriculture, Forestry and Fisheries of Japan, through the Food Nanotechnology Project, and the Japan Society for the Promotion of Science.     

Bioorganometallics: First examples of cyclometalated iridium(III) complexes containing di- and tripeptide ester ligands

The synthesis of bis-cyclometalated [Ir(ptpy)₂(gly-gly-OEt)] (2, ptpy = 2-(p-tolyl)pyridinato; gly-gly-OEt = glycylglycine ethyl ester) and [Ir(ptpy)₂(gly-gly-gly-OEt)] (3, gly-gly-gly-OEt = glycylglycylglycine ethyl ester) from the reaction of [{Ir(μ-Cl)(ptpy)₂}₂] (1) with the corresponding peptide ester hydrochlorides in the presence of NaOMe is described. The molecular structure of 2 was confirmed by a single-crystal X-ray diffraction study. The compound crystallized from dichloromethane/iso-hexane in the space group P2₁/a. In the crystal packing the molecules of 2 exhibit N–H?O hydrogen bonds to the neighbor molecules to form dimeric units. The absorption and emission spectra of 2 and 3 were recorded and exhibit these compounds as strong green-emitting complexes.     

Study of the antioxidant activity of Thymus sibthorpii Bentham (Lamiaceae)

Abstract

From the aerial parts of Thymus sibthorpii Bentham (Lamiaceae), five flavonoids apigenin (1), 7-methoxy-apigenin (2), naringenin (3), eriodictyol (4) and eriodictyol-7-glucoside (5), have been isolated together with caffeic acid methyl ester (6), rosmarinic acid (7) and rosmarinic acid methyl ester (8). The structures of the isolated compounds were established by spectroscopic methods. The extracts and the isolated compounds were tested for their free radical scavenging activity using the following in vitro assays: (i) interaction with the free stable radical of DPPH (1,1-diphenyl-2-picrylhydrazyl), (ii) inhibition of linoleic acid lipid peroxidation induced by the dihydrochloric acid of 2,2-azobis-2-amidinepropane (AAPH) and (iii) the scavenging activity of enzymatically produced superoxide anion. Their inhibitory activity toward soybean lipoxygenase was evaluated in vitro, using linoleic acid as a substrate. The antioxidant results of the extracts are discussed in terms of their constitution in phenolic compounds, which were determined following the Folin–Ciocalteu method.     

Synthesis and in vitro evaluation of fluorinated styryl benzazoles as amyloid-probes

The formation of proteinaceous aggregates is a pathognomonic hallmark of several neurodegenerative disorders such as Alzheimer’s and Parkinson’s diseases. To date, the final diagnostic for these diseases can only be achieved by immunostaining of post-mortem brain tissues with the commonly used congo red and Thioflavin T/S amyloid-dyes. The interest in developing amyloid-avid radioprobes to be used for protein aggregates imaging by positron emission tomography has grown substantialy, due to the promise in assisting diagnosis of these disorders. To this purpose, the present work describes the synthesis and characterization of four novel fluorinated styryl benzazole derivatives 1–4 by means of the Wittig reaction, as well as their in vitro evaluation as amyloid-probing agents. All compounds were obtained as mixtures of geometric E and Z isomers, with the preferable formation of the E isomer. Photoisomerization reactions allowed for the maximization of the minor Z isomers. The authentic 1–4E/Z isomers were isolated after purification by column chromatography under dark conditions. Profiting from the fluorescence properties of the different geometric isomers of 1–4, their binding affinities towards amyloid fibrils of insulin, α-synuclein and β-amyloid peptide were also measured. These compounds share similarities with Thioflavin T, interacting specifically with fibrillary species with a red-shift in the excitation wavelengths along with an increase in the fluorescence emission intensity. Apparent binding constants were determined and ranged between 1.22 and 23.96 μM⁻¹. The present data suggest that the novel fluorinated styryl benzazole derivatives may prove useful for the design of ¹⁸F-labeled amyloid radioprobes.     

Effects of surfactants on emulsification and secondary structure of lysozyme in aqueous solutions

This paper reports our investigations on the secondary structure of lysozyme in aqueous solution with D₂O and comparing systems emulsified with ionic and non-ionic amphiphiles, respectively. The opposite effect of concentration of surfactants on the lysozyme aqueous system was studied and the activity of lysozyme by the turbidimetric assay with different kinds of surfactant was compared. The effect of different surfactants on emulsification volume formed was observed and discussed. The different interactive patterns between lysozyme and ionic and non-ionic surfactants, such as sodium dodecyl sulfate (SDS), cetyl trimethyl ammonium bromide (CTAB) and Triton-X100 (Isooctoylphenoxypolyethoxy ethanol), respectively, was studied with FTIR. A simple relationship between the secondary structure and denaturation of protein is given for the emulsification of lysozyme in aqueous solutions. It is important for understanding the stabilization and avoiding the emulsions in the extraction process that the interactions between the proteins and surfactants which leads to the formation of such complexes are characterized. The utility of surfactants as a de-emulsifying agent for the commercial process to extract penicillin G from the filtrate of fermentation broth was consistent with these results.     

Minor diterpenoid glycosides from the leaves of Stevia rebaudiana

From the commercial extract of the leaves of Stevia rebaudiana, three new diterpenoid glycosides were isolated besides eight known steviol glycosides including stevioside, rebaudiosides A–F and dulcoside A. The structures of the three compounds were identified as 13-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl) oxy]-kaur-16-en-18-oic acid-(6-O-β-d-xylopyranosyl-β-d-glucopyranosyl) ester (1), 13-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl) oxy]-17-hydroxy-kaur-15-en-18-oic acid β-d-glucopyranosyl ester (2), and 13-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl) oxy]-17-oxo-kaur-15-en-18-oic acid β-d-glucopyranosyl ester (3) on the basis of extensive NMR and MS spectral studies. Another known diterpenoid glycoside, 13-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl) oxy]-kaur-15-en-18-oic acid β-d-glucopyranosyl ester (4) was also isolated and its complete NMR spectral assignments were made on the basis of COSY, HSQC and HMBC spectral data.     

Whole cell catalyzed esterification of fatty acids to biodiesel using Aspergillus sp.

Abstract

Powdered biomass of Aspergillus sp. (RBD01) was used to carry out esterification of long chain fatty acids for biodiesel production. Dry biomass of Aspergillus sp. at 20% (w/w) with respect to the fatty acid was able to completely esterify oleic acid to ethyl ester at 35°C, in 36 h, with step wise addition of alcohol. Similar conditions also resulted in yield of 64.5% and 58% of ethyl ester from stearic acid and palmitic acid, respectively. However, the presence of methanol resulted in 87.5%, 71% and 41% of methyl ester from oleic, palmitic and stearic acid. Furthermore, it was found that the efficiency of biomass decreased by only 10% with its repeated use up to four cycles.