Identification of Pseudozyma graminicola CBS 10092 as a producer of glycolipid biosurfactants, mannosylerythritol lipids

A basidiomycetous yeast, Pseudozyma graminicola CBS 10092, was found to accumulate a large amount of glycolipids in the cultured medium when grown on soybean oil as the sole carbon source. Based on thin layer chromatography, the extracellular glycolipids gave spots corresponding to those of mannosylerythritol lipids (MELs), which are highly functional and promising biosurfactants. From the structural characterization by 1H and 13C NMR, the main product was identified as 4-O-[(4'-mono-O-acetyl-2', 3'-di-O-alka(e)noyl)-beta-D-mannopyranosyl]-D-erythritol, which is a highly hydrophilic derivative of MELs known as MEL-C. According to high-performance liquid chromatography analysis, the main product, MEL-C, comprised approximately 85% of all the MELs, and the total amount reached approximately 10 g/L for 7 days. The fatty acids of the present MEL-C consisted of mainly C6, C8 and C14 acids, considerably different from those of MEL-C produced by other Pseudozyma strains such as P. antarctica and P. shanxiensis. The observed critical micelle concentration (CMC) and the surface-tension at CMC of the MEL-C were 4.0 x 10(-6) M and 24.2 mN/m, respectively, while those of MEL-A, the most intensively studied MEL, were 2.7 x 10(-6) M and 28.4 mN/m, respectively. This implied that the MEL-C has higher hydrophilicity than conventional MELs hitherto reported. In addition, on a water-penetration scan, the MEL-C efficiently formed the lamella phase (Lalpha) at a wide range of concentrations, indicating its excellent self-assembling properties. From these results, the newly identified MELs produced by P. graminicola are likely to have great potential for use in oil-in-water type emulsifiers and/or washing detergents, and would thus facilitate a broad range of applications for the promising yeast biosurfactants.     

Efficient production of di- and tri-acylated mannosylerythritol lipids as glycolipid biosurfactants by Pseudozyma parantarctica JCM 11752(T)

Mannosylerythritol lipids (MELs) are one of the most promising biosurfactants known, because of their multifunctionality and biocompatibility. In order to attain an efficient production of MELs, Pseudozyma parantarctica JCM 11752(T), which is a newly identified strain of the genus, was examined for the productivity of MELs at different culture conditions. The yeast strain showed significant cell growth and production of di-acylated MELs even at 36 degrees C. In contrast, on conventional high-level MEL producers including P. rugulosa, the MEL yield considerably decreased with an increase of the cultivation temperature at over 30 degrees C. On P. parantarctica, soybean oil and sodium nitrate were the best carbon and nitrogen sources, respectively. Under the optimal conditions on a shake-flask culture at 34 degrees C, the amount of di-acylated MELs reached over 100 g/L by intermittent feeding of only soybean oil. Interestingly, the yeast strain produced tri-acylated MELs as well as di-acylated ones when grown on the medium containing higher soybean oil concentrations than 8% (vol/vol). The production of tri-acylated MELs was significantly accelerated at between 34 and 36 degrees C. With 20 % (vol/vol) of soybean oil at 34 degrees C, the yield of tri-acylated MELs reached 22.7 g/L. The extracellular lipase activity considerably depended on the culture temperature, and became the maximum at 34 degrees C; this would bring the accelerated production of tri-acylated MELs. Accordingly, the present strain of P. parantarctica provided high efficiency in MEL production at elevated temperatures compared to conventional MEL producers, and would thus be highly advantageous for the commercial production of the promising biosurfactants.     

Characterization of new types of mannosylerythritol lipids as biosurfactants produced from soybean oil by a basidiomycetous yeast, Pseudozyma shanxiensis

Mannosylerythritol lipids (MELs) are glycolipid biosurfactants produced by the yeast strains of the genus Pseudozyma. These show not only the excellent surface-active properties but also versatile biochemical actions. In course of MEL production from soybean oil by P. shanxiensis, new extracellular glycolipids (more hydrophilic than the previously reported MELs) were found in the culture medium. As a result of the structural characterization, the glycolipids were identified as a mixture of 4-O-[(2', 4'-di-O-acetyl-3'-O-alka(e)noyl)-beta-D-mannopyranosyl]-D-erythritol and 4-O-[(4'-O-acetyl-3'-O-alka(e)noyl-2'-O-butanoyl)-beta-D-mannopyranosyl]-D-erythritol. Interestingly, the new MELs possessed a much shorter chain (C(2) or C(4)) at the C-2' position of the mannose moiety compared to the MELs hitherto reported, which mainly possess a medium-chain acid (C(10)) at the position. They would thus show higher hydrophilicity and/or water-solubility, and expand the development of the environmentally advanced yeast biosurfactants.     

Formation of W/O microemulsion based on natural glycolipid biosurfactant, mannosylerythritol lipid-a

Mannosylerythritol lipid-A (MEL-A) is a glycolipid biosurfactant abundantly produced from soybean oil by microorganisms at a yield of up to 100 g/L. In this study, the formation of water-in-oil (W/O) microemulsion based on the single component of MEL-A was confirmed using dynamic light scattering (DLS) and freeze fracture electron microscopy (FF-EM). DLS and FF-EM measurements revealed that the diameter of the microemulsion increases with an increase in water-to-surfactant mole ratio (W(0)) ranging from 20 to 60 nm, and the maximum W(0) value was found to be 20, which is as high as that of soybean lecithin. Glycolipid biosurfactant has a great potential for the formation of W/O microemulsion without using any cosurfactants.     

高效节能新型煤气发生炉的开发与应用

在原煤气发生炉结构的基础上,从炉底的灰盘与底盘、齿轮传动部分及防尘密封结构改进着手,开发设计高效节能新型煤气发生炉,经运行考核验证,能提高生产效率,降低能耗,延长设备使用寿命。     

过程能量综合技术在味精生产企业能量优化中的应用（Ⅰ）——味精企业“三环节”能量结构模型的建立与用能分析评价

根据所建立的味精企业"三环节"能量结构模型,对某味精生产企业的能量系统进行了热量平衡、火用平衡以及能量效率的计算和分析,并分别对能量利用环节、能量回收环节和能量转换环节的能量利用、能量回收和能量转换效率进行了评价,分析研究了该厂各环节能量效率低下的因素,指出了该厂存在着巨大的节能潜力。     

Seeds of the east african savannah bushBalanites orbicularis as a possible new source of lipids for commercial use

The fruits of the native East African savannah bushBalanites orbicularis Sprague were analyzed for their chemical composition. The seeds of these fruits were found to be rich in triacylglycerols with a high content of oleic and linoleic acids. Due to the high essential fatty acid content and the absence of toxic cyclic and oxy fatty acids, the oil from these seeds could be an extremely valuable form of nutrition. The significance of this plant is discussed briefly pertaining to its importance as a food and energy source in countries with arid regions.     

Fabricating a new immobilization matrix based on a conjugated polymer and application as a glucose biosensor

A new monomer named 4-(dihexylamino)9,12-di(thiophen-2-yl)-7H-benzo[de]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one (ThBN) is synthesized and used as a potential glucose biosensor after electropolymerization of the ThBN on the graphite pencil electrode. The amount of glucose is determined according to the decrease in the amount of oxygen by using cyclic voltammetry technique. Herein, conjugated polymer of ThBN is used as a immobilization matrix. The synthesized PThBN is found to be effective enzymatic biosensor having wide linear glucose determination range between 2.975 × 10⁻³ and 2.087 mM with a limit of detection of 0.0304 mM and a sensitivity of 0.1326 μA/mM cm². This potential enzymatic biosensor has been also tested in commercial samples and found to be useful to detect the glucose concentration.     

Tar removal from the producer gas of a small scale downdraft gasifier using a fatty acid based,wet packed-bed scrubber

Small scale gasification combined heat and power (CHP) systems offer an alternative to diesel fuelled generators for power generation in remote communities and industrial sites. Tar and particulates in the producer-gas can damage the internal combustion engine generator and increase operation and maintenance costs. In this work, we present a novel trickle-bed scrubber using filtered waste cooking oil as a cost effective and easy-to-operate gas clean-up method for a small CHP system. The performance of the trickle-bed scrubber was compared against a packed-bed filter utilizing woodchips in a 20 kW_th downdraft gasifier. Used-cooking oil was selected as the solvent and woodchips as the bed-material as these are readily available, inexpensive, and can be recycled in the gasifier as fuel. A woodchip packed-bed filter reduced the tar and particulate matter (PM) in the producer gas from gasification of spruce chips (11% moisture) from 1.6 to 1.4 g/Nm³ and from 0.16 to 0.087 g/Nm³ respectively. The trickle-bed scrubber was able to reduce the tar and PM in the producer gas from gasification of pinewood (8% moisture) from 1.38 to 0.28 g/Nm³, and 0.209 to 0.082 g/Nm³, respectively. Tar and PM removal efficiency improved by 60% and 29% respectively. Components such as benzene, toluene, naphthalene, and biphenylene were the major tar components. After passing the trickle-bed, most tar was removed, with a preference for removal of multi-ringed aromatics and gravimetric tars. Parameters such as the tar and particulate concentration, feedstock moisture content, and feedstock source affect the performance of the gas clean-up system.     

Effect of hepatoma on host liver,heart and lung lipids as tumor growth progresses

A large group of rats was transplanted with hepatoma 7288CTC and 4 animals were sacrificed at 3-day intervals for four weeks. Lipid class concentrations, fatty acid class compositions, and the distribution ofcis octadecenoate positional isomers in the major lipid classes were determined for heart, liver and lung at each time period. The hearts of host animals decreased in dry weight as hepatoma growth progressed. At day 30, heart weights were less than two-thirds of initial weights. Lipid class concentrations changed in all three tissues: cholesterol and free fatty acids increased in liver; triglycerides and cholesterol decreased and then increased in heart; and cholesterol, triglycerides and PC decreased in lung as tumor growth progressed. Hexadecenoate percentages exhibited a progressive decrease in all the lipid classes of heart and liver. Although total octadecenoate percentages showed only minor changes, oleate concentrations generally increased and vaccenate levels decreased in heart and liver lipids as tumor growth progressed. Palmitoleate, precursor of vaccenate, exhibited decreased concentrations early that resulted in decreased vaccenate levels. Decreased palmitoleate concentrations suggest inhibition of the Δ9 desaturase system, but normal oleate concentrations complicate this interpretation. Most of the changes in the lipids were detectable 3–6 days after transplantation, indicating the hepatoma affects the lipid metabolism of the host animal early and well in advance of nutritional stresses.     

Synthesis,structure, and photocatalytic property of a new hybrid compound based on unusual bi-silver-capped polyoxometalates

A new compound based on capped polyoxometalates (POMs), [Ag(phen)₂]₂(Agphen)₂SiW₁₂O₄₀ (phen = 1,10-phenanthroline), has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, infrared spectrum, UV–vis electronic spectrum, elemental analyses, and powder X-ray diffraction pattern. The structural feature of compound 1 is that each [SiW₁₂O₄₀]^4 − (SiW₁₂) cluster capped by two (Agphen)⁺ fragments. To the best of our knowledge, the compound 1 represents the first example of hybrid compound based on bi-silver-capped POMs to date. The photocatalytic properties of compound 1 were also investigated in detail and the results of photocatalytic experiment show that compound 1 can be used as a photocatalyst towards the decomposition of organic pollutant methylene blue (MB).     

Identification of mNeonGreen as a pH-Dependent,Turn-On Fluorescent Protein Sensor for Chloride

Chloride-sensitive fluorescent proteins generated from laboratory evolution have a characteristic tyrosine residue that interacts with a chloride ion and π-stacks with the chromophore. However, the engineered yellow-green fluorescent protein mNeonGreen lacks this interaction but still binds chloride, as seen in a recently reported crystal structure. Based on its unique coordination sphere, we were curious if chloride could influence the optical properties of mNeonGreen. Here, we present the structure-guided identification and spectroscopic characterization of mNeonGreen as a turn-on fluorescent protein sensor for chloride. Our results show that chloride binding lowers the chromophore pK_a and shifts the equilibrium away from the weakly fluorescent phenol form to the highly fluorescent phenolate form, resulting in a pH-dependent, turn-on fluorescence response. Moreover, through mutagenesis, we link this sensing mechanism to a non-coordinating residue in the chloride binding pocket. This discovery sets the stage to further engineer mNeonGreen as a new fluorescent protein-based tool for imaging cellular chloride.     

Development of a new abrasion tester based on planetary motion

Particulate products are subjected to forces of different direction and magnitude during production, storage and transportation. These forces may lead to dust formation or even fracture of the particles. The prediction of how a particle will behave in a process requires a particle breakage tester. For every breakage mechanism a different tester is required, to isolate the physics acting on the particles. In this paper the new abrasion tester is presented, testing mainly tangential forces acting on the particles.     

Dyes based on a 1,4‐naphthoquinone skeleton as new type II photoinitiators for radical polymerisation

Photoredox pairs consisting of 1,4‐naphthoquinone dyes and commercially available hydrogen donors (2‐mercaptobenzoxazole, 2‐mercaptobenzothiazole, 2‐mercaptobenzimidazole and 2,5‐dimercapto‐1,3,4‐thiadiazole) are found to be effective initiator systems for the radical polymerisation of trimethylolpropane triacrylate under visible light. The efficiency of these initiator systems is discussed in terms of the free energy change for the electron transfer process from the dye to the hydrogen donor. The results show that the photoinitiation ability of tested photoredox pairs depends on the structure of both the dye and the hydrogen donor.     

Synthesis, electrochemical and optical studies of new cyanopyridine based conjugated polymers as potential fluorescent materials

In this communication we describe the design and synthesis of four new conjugated polymers (P1-P4) carrying cyanopyridine in their backbone via Wittig condensation technique. Their structures were well established by FTIR, ¹H NMR, elemental analysis and gel permeation chromatographic techniques. They exhibited good thermal stability with the onset decomposition temperature around 300-350 °C in nitrogen atmosphere. Further, their electrochemical, linear and third-order non-linear optical properties have been investigated. The polymers showed low electrochemical band gaps in the range of 1.77-1.99 eV and displayed very good fluorescence emission property in various polar solvents. The fluorescence quantum yields of polymers P1-P4 in tetrahydrofuran (THF) were found to be 35, 42, 38 and 34%, respectively. The effective two-photon absorption coefficients (β) for the polymers were determined by Z-Scan technique and were found to be 1.34 × 10⁻¹¹, 1.24 × 10⁻¹¹, 3.04 × 10⁻¹¹ and 1.85 × 10⁻¹¹ m/W for polymers P1-P4, respectively.     

Identification of a Triterpenoid Saponin from a Crucifer, Barbarea vulgaris, as a Feeding Deterrent to the Diamondback Moth, Plutella xylostella

Larvae of the diamondback moth, Plutella xylostella, a crucifer specialist, refuse to feed on a crucifer, Barbarea vulgaris, because of the presence of a feeding deterrent, which is extractable with chloroform. We isolated a feeding deterrent from B. vulgaris leaves, by successive fractionations with silica-gel, ODS, i.e., C₁₈ reversed phase, and Sephadex LH-20 column chromatographies, and ODS-HPLC, guided by a bioassay for feeding deterrent activity. The structure of the compound was determined to be a monodesmosidic triterpenoid saponin, 3-O-[O--D-glucopyranosyl-(14)--D-glucopyranosyl]-hederagenin, based on FAB-MS, ¹H- and ¹³C-NMR spectra, and hydrolysis experiments. When the compound was applied to cabbage leaf disks at greater than 0.18 g/mm², consumption of the disks by third instars was less than 11% of control disks treated with the solvent alone. Furthermore, all first instars died on the disks treated with the same concentrations. Because the concentration of the compound in the fresh leaves of B. vulgaris was comparable to the effective dose in the cabbage leaf disk tested, we conclude that the unacceptability of B. vulgaris to P. xylostella larvae is primarily due to this saponin.     

Synthesis and properties of a new, branched polyhydridocarbosilane as a precursor for silicon carbide

Polymerization of Cl₂Si(CH₃)CH₂Cl with Mg in THF, followed by reduction with LiAlH₄, gave a polycarbosilane with Si-H groups and branches at the Si atoms. The polymer could be cross-linked thermally at 150°C. Pyrolysis of the cross-linked material gave SiC with a yield of 70%.Presented at the XXVIth Silicon-Symposium, Indiana University-Purdue University at Indianapolis, March 26–27, 1993.     

新甜味剂三氯蔗糖的合成工艺进展

从多方面综述了三氯蔗糖的合成方法近期的研究进展,如全官能团保护法、单官能团法、化学-酶法等,并对各个合成工艺的优劣进行了评析,借以进一步促进新工艺技术与应用领域的融合与发展。     

Synthesis,characterization, and application of a triazene‐based polysulfone as a dye adsorbent

Novel triazene‐based polysulfone, poly 4‐(4‐aminophenylsulfonyl)diazobenzene, was synthesized from 4‐[(4‐aminobenzene)sulfonyl]aniline (Dapsone) in the presence of sodium nitrite/silica sulfuric acid system, under solvent‐free conditions, and also in aqueous media to compare their polymerization process and the products. The structures of the obtained polymers under the two conditions were characterized for the first time in this investigation by several analytical and spectroscopic methods such as FT‐IR, ¹H‐NMR, UV–vis, thermogravimetric and differential thermal analyses, gel permeation chromatography, mass spectrometry, and CHN micro‐elemental analysis. The results showed that both polymerization processes had made the same product; nevertheless, the solvent‐free conditions afforded silica‐coated poly 4‐(4‐aminophenylsulfonyl)diazobenzene. In another study, the ability of the silica‐coated polymer, to remove some usual applied water‐soluble dyes by spectrophotometric detection, was measured in which cationic structure dyes such as Rhodamine B and Cationic blue 41 were preferably adsorbed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013