红发夫酵母发酵虾青素的研究

红发夫酵母分离于北美西部高山地区和日本一些岛屿上落叶树的渗出液中，因其所产主要色素为在水产养殖、食品和医药工业有广阔应用前景的虾青素而成为研究的热点。本论文对红发夫酵母Phaffia rhodozyma 的生长特性、培养参数与培养基组分对生长和虾青素积累的影响及其优化、虾青素合成的调节控制、虾青素的提取测定及红发夫酵母耐高温菌种的诱变进行了系统的研究。 虾青素是红发夫酵母的胞内色素，要对其进行分析首先要对红发夫酵母进行破壁处理，实验发现二甲亚砜是最有效的破壁溶剂，用氯仿和丙酮可以有效地把类胡萝卜素从二甲亚砜破壁后的红发夫酵母细胞中提取出来。 在固定摇床转速为200 rpm，温度为20 ℃的条件下，当种龄为36 h，以10％的接种量接入装液量为30 mL的250 mL三角瓶，初始pH为5.5时最有利于红发夫酵母的生长及类胡萝卜素的合成。 本实验中红发夫酵母最佳利用碳、氮源分别为蔗糖和蛋白胨，但蛋白胨价格昂贵，不适宜作单一氮源，因此使用硫酸铵和酵母膏作为复合氮源。 本论文采用了BP神经网络结合遗传算法的方法来优化红发夫酵母的发酵培养基，得到红发夫酵母发酵培养基的最佳配比为：蔗糖45.10 g/L、硫酸铵3.00 g/L、硫酸镁0.80 g/L、磷酸二氢钾1.40 g/L、酵母膏3.00 g/L、氯化钙0.50 g/L，使用优化后的培养基发酵类胡萝卜素产量达到8.20 mg/L，干重达到9.47 g/L，类胡萝卜素的产量比起始培养基提高了95.90%，干重提高了89.40%。 从代谢途径出发对红发夫酵母合成虾青素调控调控，选择谷氨酸、乙醇、VB1作为添加剂，通过正交试验设计得出三者添加水平分别为0.2 g/L，0.1% (V/V)，10 mg/L时，类胡萝卜素产量提高了25.73%，达到了10.31mg/L。 通过上述优化培养，本论文中红发夫酵母的虾青素产量从1.33 mg/L提高到9.12 mg/L，产量提高了6.86倍；总类胡萝卜素产量从4.23 mg/L提高到10.31 mg/L，产量提高了2.44倍；细胞干重从5.00 g/L提高到11.35 g/L，提高了2.27倍，总体提高效果显著。 红发夫酵母属于中低温菌，本论文采用紫外复合诱变的方式，通过高温筛选，得到一株能在35 ℃下能生长的突变株，但所产类胡萝卜素中虾青素所占比例很小，可能是诱变改变了红发夫酵母的代谢途径，阻断了虾青素的合成。 Phaffia rhodozyma is a heterobasidiomyceteous yeast that was originally isolated from the slime fluxes of brich tree wounds in mountain regions of northern Japan and southern Alaska. Phaffia rhodozyma produces astaxanthin as its principal carotenoid pigment, which has potential applications in acquaculture, food and pharmaceutical industry. This paper researched ways to break cell, analysis of astaxanthin, characteristics of growth, culture parameters and the effects of components of medium on growth and astaxanthin formation , optimization of culture medium, control of astaxanthin synthesis and mutagenesis of Phaffia rhodozyma. It is necessary to disrupt the yeast cell for extracting astaxanthin considering the yeast accumulating carotenoids in cell. Dimethyisulphoxide was the most effective solvent for breaking the yeast cell; acetone and chloroform were effective to extract carotenoids out of the disrupted cell. The optimum pH for growth and carotenoids synthesis is 5.5, the optimum medium volume is 30 mL (in 250 mL flask), the optimum culture time of inoculum is 36 h, the optimum inoculum concentration is 10%. The research on culture medium showed: sucrose is the best one of 6 carbon sources for growth and astaxanthin synthesis. Peptone is the best nitrogen source for growth and astaxanthin synthesis. Uniform Design was used for trial design of the formula medium components, then back-propagation neural network was established to modeling the relationships between the carotenoid yield and the concentration of medium components. Genetic algorithm (GA) was used for global optimization of the model. The optimum combination of the medium was obtained: sucrose 45.10 g/L, ammonium sulfate 3.00 g/L, magnesium sulfate 0.80 g/L, potassium dihydrogen phosphate 1.40 g/L, yeast extract 3.00 g/L, calcium chloride 0.50 g/L. The yield of carotenoid reached 8.20 mg/L, which was 95.90% higher than that of the original medium. Glu, VB1 and ethanol were selected as fermentation addictives, after Orthogonal Test, the carotenoid contents increased by 25.73% when adding 0.16 g/L Glu, VB1 10 mg/L and ethanol 0.1% (V/V). After the above optimization, the astaxanthin content increased 6.86 folds, which is 9.12 mg/L. The carotenoids content increased 2.44 folds, which is 10.31 mg/L. The biomass increased 2.27 folds, which is 11.35 g/L. Phaffia rhodozyma grows in the mild temperature range of 0 to 27 ℃, in this work, a thermotolerant mutant was selected through UV-irradiation. It can grows at 35 ℃, and showed increased carotenoid content. The optimal growth temperature for this mutant is 30 ℃. But the mutant can only produce carotenoids with little astaxanthin accumulation.

CO selective oxidation in a microchannel reactor for PEM fuel cell

It is indispensable to remove CO at the level of less than 50ppm in H-2-rich feed gas for the proton exchange membrane (PEM) fuel cells. In this paper, catalyst with high activity and selectivity, and a microchannel reactor for CO preferential oxidation (PROX) have been developed. The results indicated that potassium on supported Rh metal catalysts had a promoting effect in the CO selective catalytic oxidation under H-2-rich stream, and microchannel reactor has an excellent ability to use in on-board hydrogen generation system. CO conversion keeps at high levels even at a very high GHSV as 500 000 h(-1), so, miniaturization of hydrogen generation system can be achieved by using the microchannel reactor. (C) 2004 Elsevier B.V. All rights reserved.

Study of an electroosmotic pump for liquid delivery and its application in capillary column liquid chromatography

A packed-bed electroosmotic pump (EOP) was constructed and evaluated. The EOP consisted of three capillary columns packed in parallel, a gas-releasing device, Pt electrodes and a high-voltage power supply. The EOP could generate output pressure above 5.0 MPa and constant flow rate in the range of nl/min to a few mul/min for pure water, pure methanol, 2 mM potassium dihydrogenphosphate buffer, the buffer-methanol mixture and the pure water-methanol mixture at applied potentials less than 20 W The composition of solvent before/after pumping was quantitatively determined by using a gas chromatograph equipped with both flame ionization detector and thermal conductivity detector. It was found that there were no apparent changes in composition and relative concentrations after pumping process for a methanol-ethanol-acetonitrile mixture and a methanol-water mixture. Theoretical aspect of the EOP was discussed in detail. An capillary HPLC system consisting of the EOP, an injection valve, a 15 cm x 320 mum i.d., 5 mum Spherigel C(18) stainless steel analytical column, and an on-column UV detector was connected to evaluate the performance of the EOP. A comparative study was also carried out with a mechanical capillary HPLC pump on the same system. The results demonstrated that the reproducibility of flow rate and the pulsation-free flow property of the EOP are superior to that of mechanical pump in capillary HPLC application. (C) 2004 Elsevier B.V. All rights reserved.

聚丙烯酰胺防治水土流失的效果

Field plots observations indicate that applying polyacrylamide to soil can reduce surface runoff by 18 4%～46 8%,decrease soil erosion by 13%～55%,and increase soil organic matter,alkali-hydrolyzable nitrogen,available phosphate,available potassium in different degrees compared with not application.In addition,applying polyacrylamide can also increase corn yield by 540 5kg·ha -1 ,and net income by 240 5ha.

Calibration of standard seawater in electrical conductivity

The procedure adopted by the Standard Seawater Service for the calibration of Standard Seawater in electrical conductivity relative to a defined potassium chloride solution is described

膜荚黄芪氮磷钾优化施肥模式研究

采用氮、磷、钾三因素二次D-饱和最优设计,通过田间试验建立了氮、磷、钾的施肥量编码值与膜荚黄芪根产量、多糖含量的效应函数。结果表明,氮、磷、钾肥对膜荚黄芪根产量的增产作用大小依次为氮肥>钾肥>磷肥;氮、磷、钾肥对黄芪多糖含量的作用大小依次为钾肥>磷肥>氮肥,其中钾肥为负效应,氮肥、磷肥为正效应。寻优结果表明,膜荚黄芪目标产量在6000～7000 kg/hm~2之间,95%置信区间的优化施肥量为N 66.85～102.92 kg/hm~2、P_2O_5 64.64～94.95 kg/hm~2、K_2O 119.78～166.48kg/hm~2;膜荚黄芪多糖含量在13%～14%之间,95%置信区间的优化施肥量为N 66.85～102.92kg/hm~2、P_2O_5 64.64～94.95kg/hm~2、K_2O 119.78～166.48 kg/hm~2;膜荚黄芪高产优质高效栽培优化施肥量为N 99.52～102.92kg/hm~2、P_2O_5 94.20～94.95kg/hm~2、K_2O 119.78～166.48kg/hm~2,N、P_2O_5、K_2O的最佳比例为1:0.92～0.95:1.16～1....

施钾水平对烟叶含钾量的影响

通过盆栽试验 ,采用定位叶片的方法 ,进行不同钾肥用量试验 ,研究了增施钾肥对石灰性土壤上烤烟吸钾和土壤供钾的影响及提高石灰性土壤上烤烟含钾量的可能途径。结果表明 ,增施钾肥可以显著提高烟叶含钾量 ;而当施钾量达一定水平时 ,只有大幅度增加钾肥施用量 ,烟叶含钾量才显著增加 ,但对烟叶产量影响不大。施钾对烟叶含钾量的提高作用在生育后期最为显著。保证生育后期充足的钾素供应对提高烟叶含钾量可能具有重要意义

陕北中部丘陵区土壤肥力现状及提高土地生产力的途径

调查分析了延安宝塔区和安塞县 7个乡镇近三年来的粮食生产 ,肥料投入以及各土地类型的土壤肥力状况 ,表明 :投入的化肥中 ,氮肥以低浓度养分的碳铵为主 ,平均占肥料总量的 38.3% ,从施入土壤的 N、P、K养分来看 ,K比例很小 ,结构不合理。土壤肥力总体水平低 ,且不同土地类型差异大 ;由于各乡镇自然和经济状况的差异 ,土地投入量不同 ,从而导致粮食产量相差悬殊 ,并且年际波动大。提高土地生产力的有效途径是培肥土壤和大力推广农作物高产栽培技术

宁夏黄土区不同植物群落土地利用方式对土壤质量的影响

本文研究了宁夏南部山区典型植物群落土地不同利用方式下土壤质量的变化。结果表明:(1)典型长芒草群落土地,开垦地比封禁地土壤有机质、全氮、全磷、速效氮、速效磷、速效钾养分含量明显降低,降低幅度分别为19.5%、20.1%、17.6%1、3.0%、77.8%和47.5%。脲酶活性为开垦地>封禁地,蔗糖酶则表现为封禁地>开垦地,中性磷酸酶差异不明显。(2)铁杆蒿群落土地三种利用方式下:放牧地土壤有机质、全氮、全磷、速效钾等养分含量较封禁地与开垦地有一定幅度的增加;放牧地的土壤脲酶、蔗糖酶和中性磷酸酶活性均高于封禁和开垦的同土层土壤,封禁地的脲酶和蔗糖酶次之,开垦地的脲酶和蔗糖酶活性最小,开垦地的中性磷酸酶活性高于封禁地。脲酶活性在土层之间变化较小,最高为放牧地表层177.6 mg/(kg.h),最低为开垦地表下层114.5 mg/(kg.h),蔗糖酶活性层次之间变化明显,其中放牧地表层为表下层的3倍左右。长芒草群落土壤表层各级微团聚体表现为封禁地远大于开垦地,铁杆蒿群落土地不同利用方式下各级微团聚体表现不同,结构系数表现为表层>表下层,保持率则为表层<表下层。结构系数与保持率均表现为封禁地>放牧地>开垦地。(3)在...

有机酸对茄子生长发育及产量的影响

采用盆栽试验,研究了2种含钾土壤条件下不同有机酸对茄子产量和生长发育的影响。结果表明:通过叶面喷施有机酸可提高茄子单果重,改善植株的生长发育状况。其中,有机酸钾、甲酸、柠檬酸、乙酰丙酸与对照之间有显著差异;高钾土壤高于低钾土壤产量,且差异显著。有机酸的增产效果依次为有机酸钾>甲酸>柠檬酸>乙酰丙酸>草酸>丙酸>乙酸。

原子吸收光谱法测定膜荚黄芪不同器官矿质元素含量

应用混合酸HNO3-HClO4(4∶1)在常压微沸条件下对膜荚黄芪根系及茎叶样品进行消解,采用原子吸收光谱法测定了膜荚黄芪不同器官即根及茎叶中五种人体必需矿质元素K,Fe,Zn,Mn和Cu含量,并对结果进行了统计分析与比较。该方法标准曲线相关系数为0.997 3~0.999 9,加标回收率为92.88%~109.25%,相对标准偏差(RSD,n=5)为0.393 5%~3.175 2%。方法简单,结果可靠。结果显示,膜荚黄芪根及茎叶中5种矿质元素含量顺序均为K>Fe>Zn>Mn>Cu。膜荚黄芪不同器官矿质元素含量不同,根中富含Fe,Zn,Cu元素,根内Fe含量是茎叶的1.54倍。茎叶中也含有丰富的矿质元素,特别是K和Mn元素。茎叶中K含量是根的1.63倍,这与黄芪的药效相符合。试验结果将为研究矿质元素在黄芪植株中的分布以及矿质元素含量与黄芪药效相关性提供理论依据。

供钾方式对烟叶含钾量的影响

通过大田试验 ,研究了不同供钾方式对烟叶含钾量的影响及提高石灰性土壤上烤烟含钾量的可能途径。结果表明 ,施钾能显著提高烟叶产量 ,其中以粉肥结合喷优丰处理效果最好。在干旱条件下 ,增施钾肥可以显著提高烟叶含钾量 ,尤其能较大幅度提高中上部烟叶含钾量。粉肥对提高烟叶含钾量的效果稍优于粒肥。采用喷施“优丰 98- 2”进行根外补钾 ,可显著提高烟叶含钾量。在石灰性土壤上 ,干旱是提高烟叶含钾量的障碍因子。仅凭土壤施钾来提高烟叶含钾量 ,效果不稳定 ,受气候影响较大。土施结合喷施叶肥 ,是提高该区烤烟烟叶含钾量的有效途径。

黄土丘陵沟壑区退耕地人工柠条林土壤养分特征及其空间变异

应用时空互代方法,以柠条林为例,对黄土丘陵沟壑区不同利用年限人工林土壤养分特征、空间变异及其演变进行了系统的研究。结果表明,该区人工林土壤肥力处于较低水平;人工林表层土壤养分中速效磷和速效钾的空间变异性较大;各环境因子对土壤养分有一定的影响,海拔、坡度和坡向等环境因子与人工林地土壤养分间呈负相关关系,坡位和地形与人工林地土壤养分间呈正相关关系。随着利用年限的增加,人工林土壤养分各指标含量均增加,与利用年限有显著的相关性。有机质、全氮、有效氮和速效磷的增加量不明显,全磷含量保持相对稳定的水平,速效钾经过多年积累有明显的增加。从土壤养分指数模型可以算出该区的人工林土壤有机质、全氮、有效氮约需35a能达到中上等养分水平,速效钾则约需27a才能达到中上等养分水平。

Biosorption of Cd2+, Cu2+, Ni2+ and Zn2+ ions from aqueous solutions by pretreated biomass of brown algae

In this paper, marine brown algae Laminaria japonica was chemically modified by crosslinking with epichlorohydrin (EC1 and EC2), or oxidizing by potassium permanganate (PC), or crosslinking with glutaraldehyde (GA), or only washed by distilled water (DW). They were used for equilibrium sorption uptake studies with Cd2+, Cu2+, Ni2+ and Zn2+.

Fabrication of Superhydrophobic Cellulose-Based Materials through a Solution-Immersion Process

An industrial waterproof reagent [(potassium methyl siliconate) (PMS)] was used for fabricating a superhydrophobic surface on a cellulose-based material (cotton fabric or paper) through a solution-immersion method. This method involves a hydrogen bond assembly and a polycondensation process. The silanol, which was formed by a reaction of PMS aqueous solution with CO2, Was assembled on the cellulose molecule surface via hydrogen bond interactions. The polymethylsilsesquioxane coatings were prepared by a polycondensation reaction of the hydroxyl between cellulose and silatiol. The superhydrophobic cellulose materials were characterized by FTIR spectroscopy, thermogravimetry, and surface analysis (XPS, FESEM, AFM, and contact angle measurements).