The individually and simultaneously detection of heavy metal ions have been widely reported. However, little analyzed the difference and relationship between the two such as sensitivities and limit of detection (LOD) using irradiated natural materials. Based on the electrochemical detection of Pb(II), Cd(II), Hg(II) and Cu(II) ions, their stripping behaviors, through combining an irradiated attapulgite (IAP) at a fluence of 30kGy (IAP30) with room temperature ionic liquid (RTIL) composites coated electrodes, were compared and analyzed by square wave stripping voltammetry. The characteristic of sensitivities and LOD of IAP30/RTIL electrode towards metal ions were markedly improved in comparison with IAP electrode. The LOD of the simultaneous detection towards Pb(II), Cd(II), Cu(II) and Hg(II) using IAP30/RTIL electrode were 0.8, 0.5, 0.2 and 0.06nM, respectively. The sensitivities and LOD of Pb(II), Cd(II) in simultaneous detection were lower and higher than these in individual detection, while those of Hg(II) and Cu(II) increased and decreased in comparison with the individual detection at IAP30/RTIL or IAP30 modified electrode. An enhanced sensitivity of Hg(II) in the simultaneous detection reached 242.4μA/μM, and was the largest among four metal ions. Analysis of six groups of solutions including Pb(II)-Cd(II)-Hg(II), Cd(II)-Cu(II)-Hg(II), Pb(II)-Cu(II)-Hg(II), Cu(II)-Hg(II), Pb(II)-Hg(II), Cd(II)-Hg(II) were further performed, respectively. This study provided a novel method for the construction of sensitive electrochemical sensors of heavy metal by natural materials, and an effective reference that meet the needs of environmental control for analysis of different metal ions.

The high strength aluminous porcelain insulator with a mineral composition of kaolinite, corundum, microcline, quartz, small amounts of albite and anatase was investigated by in situ high temperature XRD (HTXRD) from 25°C to 1300°C. The amount change and reaction of minerals contained in the porcelain insulator were presented vividly. The full process occurred in successive stages: 1) kaolinite decomposed into amorphous metakaolinite in the temperature range of 500–600°C; 2) metakaolinite kept amorphous form up to about 1000°C; 3) at about 1000°C, amorphous metakaolinite generated primary mullite; 4) after bout 1200°C, microcline began to melt, forming an alkaline liquid phase which facilitated the growth of primary mullite into secondary mullite; 5) the alkaline liquid phase could etch β-quartz, resulting in the reflection intensity of β-quartz decreasing; 6) corundum was very stable in the whole heating process.

Low-energy ion implantation as a novel mutagen has been increasingly applied in the microbial mutagenesis for its higher mutation frequency and wider mutation spectra. In this work, N+ ion beam implantation was used to enhance Escherichia sp. in vitamin K-2 yield. Optimization of process parameters under submerged fermentation was carried out to improve the vitamin K-2 yield of mutant FM5-632. The results indicate that an excellent mutant FM5-632 with a yield of 123.2+/-1.6 mu g/L, that is four times that of the original strain, was achieved by eight successive implantations under the conditions of 15 keV and 60x2.6x10(13) ions/cm(2). A further optimization increased the yield of the mutant by 39.7%, i.e. 172.1+/-1.2 mu g/L which occurred in the mutant cultivated in the optimal fermentation culture medium composed of (per liter): 15.31 g glycerol, 10 g peptone, 2.89 g yeast extract, 5 g K2HPO4, 1 g NaCl, 0.5 g Mg5O4 center dot 7H(2)O and 0.04 g cedar wood oil, incubated at 33 degrees C, pH 7.0 and 180 rpm for 120 h.

采用原子吸收光谱(AAS)和X射线衍射(XRD)对山西左云粘土和贵州毕节粘土进行检测的结果表明,左云粘土与毕节粘土的各种化学成分均相差不大,但两者在物相上差别较大.左云粘土主要的物相为高岭石和石英(85％～90％),且石英含量较高(20％～40％),少量为蒙脱石、伊利石、角闪石等.毕节粘土除石英型粘土外主要的物相为高岭石(80％～90％)、绢云母(1％～20％)和石英(1％～10％),少量为蒙脱石、绿泥石、角闪石等.烧结试制结果证明通过合理配比的毕节粘土同样可以制造出合格的电瓷绝缘子.

Filamentous fungi are widely used in the field of industrial fermentation, and their morphological diversity and complex regulation during fermentation have attracted serious attention from researchers. Penicillium chrysogenum morphology, intervention and regulation, as well as the relationship between morphology and yield, were researched in this study. We have established an effective image processing method to measure several hyphal morphological parameters. These parameters were applied to quantitative analysis of morphology and the metabolic status of the product under different culture conditions. Simultaneously, morphological dynamics equations were also established. Low energy ion beam implantation and low temperature air plasma techniques were used in this work to mutate P. chrysogenum . To reveal the relationship between hyphal morphology and the production of secondary metabolites, quantitative analysis of hyphal morphological variations in the fermentation process was also carried out with mutant strains and the original strain. We constructed an RNAi vector to silence the class III chitin synthase gene chs4 to construct morphological mutants. All transformants except PcRNAi1-15 exhibited enhanced penicillin yields, especially PcRNAi1-17 and PcRNAi2-1, whose yields were 27% and 41% higher than the original strain. Our results provide a theoretical basis for understanding the regulatory mechanisms of penicillin production.

以纳豆芽孢杆菌BN-2-6为出发菌株,利用亚硝基胍(NTG)和N+注入复合诱变选育产维生素K2的突变株.经过NTG诱变后得到突变株BN-N30-1,其维生素K2的产量提高了53％,继而采用低能N+注入技术进行处理得到突变株BN-P15-11-1,维生素K2的产量比BN-N30-1提高了96％,比原始菌株提高了166％.结果表明,对纳豆芽孢杆菌BN-2-6进行NTG和低能N+注入复合诱变的效果明显,突变菌株维生素K2的产量显著提高.

An extracellular β-glucosidase from Aspergillus niger Au0847 was purified to homogeneity by precipitation with ammonium sulfate, anion exchange, and gel filtration.The purified protein was composed of two subunits with molecular masses of 110 and 120 kDa.Au0847 β-glucosidase exhibited relatively high thermostability and pH stability, and its highest activity was obtained at 65°C and pH 4.6, respectively.As a potential metalloprotein, its enzymatic activity was potently stimulated by manganese ion and DTT.The β-glucosidase displayed avid affinity and high catalytic efficiency for geniposide.Au0847 β-glucosidase has potential value as an industrial enzyme for the hydrolysis of geniposide to genipin.

This study was aimed at using corn plasm, an industrial by-product, as the main culture medium in the process of optimizing a genetically engineered Escherichia coli strain for the biosynthesis of aspartic acid. The significant effect of corn plasm, peptone, lactose, and incubation period on the activity of aspartase were noted with Plackett-Burman design and Box-Behnken design, which showed that peptone of 1.05 % (w/v), corn plasm of 8.23 % (w/v), lactose of 1.12 % (w/v), and an incubation period of 20.78 h were the optimal culture conditions. Under these conditions, the maximum predicted activity of aspartase was 3,985 U. The optimized conditions were verified by scale-up experiments, and the maximum activity of aspartase was recorded as 4,100.5 U. Adding trace metallic ions in optimized medium have an effect on the activity of aspartase. As compared with the basal medium, the initial reaction rate of aspartase increased by 2-fold, and the molar conversion rate increased to 1.5-fold. Substrate concentration (maximum of 3 M) and bioconversion temperature tolerance (maximum of 50 °C) also have obviously improved.

The property of insulators is closely related to microstructures. In order to study the difference and similarity of two kinds of insulators microstructure and thereby explore ways to improve the property of insulators further, a comparative study was carried out on three high strength porcelain insulators by XRD, SEM and ceramography. The results indicate that there exists a negative linear relationship between the porosity and the content of amorphous phase. Porosity is the main factor affecting the density of insulator body. Compared with alumina, the calcined bauxite used as raw material will cause the increase of porosity. Microcracks usually appear in vitrified area and area around quartz particle where mullite is rare, crack is obvious. Decreasing the amount of quartz in raw material and increasing the amount of mullite in vitrified area could improve the mechanical strength of porcelain insulators further.

Chitin synthases catalyze the formation of β-(1,4)-glycosidic bonds between N -acetylglucosamine residues to form the unbranched polysaccharide chitin, which is the major component of cell walls in most filamentous fungi. Several studies have shown that chitin synthases are structurally and functionally divergent and play crucial roles in the growth and morphogenesis of the genus Aspergillus although little research on this topic has been done in Penicillium chrysogenum . We used BLAST to find the genes encoding chitin synthases in P . chrysogenum related to chitin synthase genes in Aspergillus nidulans . Three homologous sequences coding for a class III chitin synthase CHS4 and two hypothetical proteins in P . chrysogenum were found. The gene which product showed the highest identity and encoded the class III chitin synthase CHS4 was studied in detail. To investigate the role of CHS4 in P . chrysogenum morphogenesis, we developed an RNA interference system to silence the class III chitin synthase gene chs4 . After transformation, mutants exhibited a slow growth rate and shorter and more branched hyphae, which were distinct from those of the original strain. The results also showed that the conidiation efficiency of all transformants was reduced sharply and indicated that chs4 is essential in conidia development. The morphologies of all transformants and the original strain in penicillin production were investigated by light microscopy, which showed that changes in chs4 expression led to a completely different morphology during fermentation and eventually caused distinct penicillin yields, especially in the transformants PcRNAi1-17 and PcRNAi2-1 where penicillin production rose by 27 % and 41 %, respectively.

以一株井冈霉素生产菌株吸水链霉菌井冈变种(Streptomyces hyroscopicus var.Jingganggen-sis yen) SHJ001为出发菌株,经能量10 keV,剂量80×2.6×1013 ion/cm2氮离子注入诱变,摇瓶筛选得到一株高产菌株SHJ381,其有效成分井冈霉素A(VAL-A)含量比出发菌株提高了13％.高产菌株具有良好的遗传稳定性.通过正交设计优化发酵培养基后,井冈霉素A含量由24 823 mg/L提高到34 488 mg/L,增加了38％.通过菌种选育和发酵优化,发酵液中VAL-A含量较最初提升了约56％,具有显著的增产效果.

An improved method was developed for enriching arachidonic acid (AA) methyl ester from microbial oil by two-step low-temperature wet fractionation. The effects of solvent, operating temperature, and solvent-to-fatty acid methyl esters (FAMEs) ratio on the enrichment of AA were investigated. The best results were achieved when n-hexane was used as solvent. With operating temperatures in the range -30 degrees C to -80 degrees C and a FAMEs-to-solvent ratio of 1:5 (v/v), the proportion of AA methyl ester isolated could be increased to 83.76 +/- 2.78% with a yield of 52.89%. The total recovery of AA methyl ester would be further increased to 90.84% by recrystallization of the solid phases. The 20C, 22C saturated fatty acids were enriched by n-hexane or petroleum ether at -30 degrees C, with concentrations increased 7.5-fold or 7.2-fold compared with their original levels, respectively. In addition, a method that combined alkali and acid catalysis of the transmethylation was the most conducive to the preparation of polyunsaturated fatty acid methyl esters. (C) 2013 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Chitin synthases, that catalyze the formation of chitin the major component of cell walls in most filamentous fungi, play crucial roles in the growth and morphogenesis. To investigate the roles of chitin synthase in Penicillium chrysogenum, we developed an RNAi system to silence the class III chitin synthase gene chs4. After transformation, mutants had a slow growth rate and shorter but highly branched hyphae. All transformants either were unable to form conidia or could form only a few. Changes in chs4 expression could lead to a completely different morphology and eventually cause distinct penicillin yields. In particular, the yield of one transformant was 41 % higher than that of the original strain.

本文研究一株分离自白云岩表面的恶臭假单胞菌DCB13菌株对CaCO3的诱导矿化作用.将恶臭假单胞菌DCB13菌株接种到修改后的牛肉膏蛋白胨液体培养基(牛肉膏3 g、蛋白胨10 g、NaCl 5 g、CaCl22 g、玻璃粉2 g、蒸馏水1L、pH 6.5～7.5)中培养7d,每24 h取培养基上清液10 mL,离心后用于测定培养液pH值、碳酸酐酶(CA)活性、HCO3及Ca2+浓度,借助X-射线衍射(XRD)、透射电子显微镜(TEM)及能谱分析(EDS)等方法分析培养7d后培养液沉淀物中是否有CaCO3生成;用不同CaCl2浓度的牛肉膏蛋白胨培养基培养该菌,培养7d后用称量法测定CaCO3的生成量,并计算Ca2+固定为CaCO3的转化率.实验结果表明,接入恶臭假单胞菌能提高该培养液的pH值,培养液中HCO3-及Ca2+浓度随培养时间有显著下降的趋势,XRD、TEM均检测出培养液底部沉淀物中有生物成因CaCO3生成,Ca2+固定为CaCO3的转化率可达25％以上.该研究结果对碳酸盐的微生物诱导合成研究提供了新的线索.

Response surface methodology(RSM) was used to optimize culture conditions for tannase production by solid-state fermentation with Aspergillus niger.Plackett-Burman design(PBD) experiment screened out three significant factors:gallnut powder content,(NH4)2SO4 concentration and spores number of inoculum.The steepest ascent experiment approached the greatest response space.Box-Behnken design(BBD) experiment was used to further optimize the significant factors.The optimum culture conditions for the production of tannase are as follows:each 250 mL flask loaded 1.0 g gallnut powder,4.4 g rice husk and 0.5 g wheat bran,liquid-solid ratio of the medium was 2∶1 and nutrient solution was constituted by(NH4)2SO4 21 g/L,MgSO4·7H2O 1 g/L and NaCl 1 g/L,with a natural pH value,the medium was inoculated with 5.7×107 spores and cultured under 30 ℃ for 4 days.Under those optimized culture conditions,the production of tannase increased from 40 U/g to 114 U/g.The reliability of the model was verified through triplicate experiments with an average yield of 115 U/g.

The production of L(+)-lactic acid (LA) by Rhizopus oryzae immobilized in polyvinyl alcohol (PVA) was investigated. To decrease diffusional resistance, we modified the PVA gel through the addition of sodium alginate and phosphate esterification. The production of L(+)-LA improved notably in the immobilized Rhizopus oryzae . Maximum L(+)-LA production (106.27 g/L), with a yield of 73.1 % and rate of 2.95 g/L·h, was obtained at a temperature of 38 °C, 6 % PVA, and 0.8 % sodium alginate. The immobilized R. oryzae was stable in 14 serial-batch cultures using non-growth medium. The immobilized beads also displayed good tolerance to low temperature and long-term storage at 4 °C with the preservation of biochemical properties.

Low-energy ion implantation as a novel mutagen has been increasingly applied in the microbial mutagenesis for its higher mutation frequency and wider mutation spectra. In this work, N+ ion beam implantation was used to enhance Aspergillus niger TA9701 in tannase yield. The optimization of process parameters under submerged fermentation was carried out to further improve the tannase yield of the mutant, Aspergillus niger J-T18. The results indicate that an excellent mutant J-T18 with a yield of 38.5 IU/mL, that is five times that of the original strain, was achieved by nine successive implantations under the conditions of 10 keV and 30–40 (×2.6 × 1013) ions/cm2. This optimization further increased the yield of the mutant by 42 %, i.e. 53.6 U/mL which occurred in the mutant cultivated in the optimal fermentation culture medium composed of: rice flour 5 %; ammonium sulfate 1 %; tannic acid 2 %; calcium carbonate 0.5 %; manganese sulfate 0.1 %; and dipotassium phosphate 0.3 %; incubated at 30°C and 180 rpm for 72 h.

In an attempt to obtain a microbial strain with higher yield of folate for industrial applications, we mutated the wild strain Candida utilis Y1.0 using a novel mutagenic process, i.e., irradiation by a helium–neon (He-Ne) laser with an output power of 20 mW and an exposure time of 20 min. The yield of folate in the mutated cells reached 1,102 ng/mL, which was 20.4-fold that of the wild strain. The mutant strain Y3.636 was relatively stable in terms of folate production through eight successive transfers of cultures and batch fermentation in a 3.7-L stirred-tank fermenter. Optimization further increased the yield of the mutant by 110 %, i.e., to 2,314 ± 13 ng/mL. The optimal culture conditions for folate production were: cultivation in fermentation culture medium composed of 62.5 g/L glucose, 15 g/L corn liquor, 3 g/L (NH4)2SO4, 3 g/L MgSO4, and 1 g/L glutamic acid; inoculum size of 9 %; incubation at 28 °C and 196 rpm for 36 h. A time-course study of cell growth and folate production by mutant strain Y3.636 strongly suggested that folate production in C. utilis is growth-associated.

Improvement of transesterification-catalyzing capability of bio-imprinted tannase is a crucial question of whether to be efficiently utilized in organic media. As for biotransformation of tannic acid to propyl gallate, bio-imprinting technique can dramatically enhance the transesterification-catalyzing capability of tannase. In this work, both cryogenic protection and immobilization were utilized to further improve its apparent catalytic capability in organic media. The results show that Triton-X-100, mannose, and magnesium ion all have a positive effect on cryogenic protection of the tannase. Particularly, combinational application of the three cryoprotectants increases its catalytic performance by 2.7-fold factor. Also, immobilization further elevates its catalytic capability by 2.1 folds. Noteworthily, the coupling application of immobilization and cryo-protection can cause the conversion rate of substrate of the bio-imprinted tannase to increase to a promising 70%. Consequently, it will be helpful to fully utilize tannase in organic phase.

In this work, we constructed an RNAi vector for attenuation of the class III chitin synthase gene chs4 , which plays a major role in hyphal growth and conidia formation. To achieve a high transformation frequency, factors affecting the preparation and regeneration of protoplasts were analyzed. The maximum numbers of protoplasts (1.41 × 10 7 mL −1 ) were released when mycelia cultured for 48 h were incubated at 30 °C for 5 h in a buffer containing 4 mg mL −1 lysing enzyme. The maximum regeneration rate (33 %) was obtained when mycelia were digested for 4 h and plated on a regeneration medium containing 1 % overlaid agar. Quantitative real-time PCR was performed to validate the transformation efficiency, and it revealed knockdown of chs4 gene in randomly selected transformants at different levels. Dramatic reductions in the formation of conidia and the hyphal growth rate were observed in most of the transformants.