Enhanced a novel β-agarase production in recombinant Escherichia coli BL21(DE3) through induction mode optimization and glycerol feeding strategy     

CHAN Zhuhua  CHEN Xinglin  HOU Yanping  GAO Boliang  ZHAO Chungui  YANG Suping  ZENG Runying 《海洋学报(英文版)》2018,(2)

Agarases are hydrolytic enzymes that act on the hydrolysis of agar and have a broad range of applications in food,cosmetics and pharmaceutical industries. In this study, a glycerol feeding strategy based on induction mode optimization for high cell density and β-agarase production was established, which could effectively control acetate yield. First, exponential feeding strategy of glycerol with different overall specific growth rates(μ) was applied in the pre-induction phase. The results showed that the low μ(μ=0.2) was suggested to be the optimal for cell growth and β-agarase production. Second, the effects of induction temperature and the inducer concentration on cell growth and β-agarase production were investigated in the post-induction phase. When induced by isopropyl-β-d-thiogalactoside(IPTG), the strategy of 0.8 mmol/L IPTG induction at 20℃ was found to be optimal for β-agarase production. When cultivation was induced by continuous lactose feeding strategy of 1.0 g/(L·h), the β-agarase activity reached 112.5 U/mL, which represented the highest β-agarase production to date.Furthermore, the β-agarase was capable of degrading G. lemaneiformis powder directly to produce neoagarooligosaccharide, and the hydrolysates were neoagarotetraose(NA4) and neoagarohexaose(NA6). The overall research may be useful for the industrial production and application of β-agarase.  相似文献   

生物制氢研究进展   总被引：1，自引：0，他引：1  

才金玲  王广策  杨素萍  周百成 《海洋科学集刊》2007,(48):176-190

目前, 世界上利用的能源90%以上都是“化石能源”(如石油、煤炭和天然气等)。随着人类不断利用这些不可再生的“化石能源”, 它将会逐渐枯竭, 且其燃烧形成的产物(如CO2和SO2等)造成的严重环境污染(如温室效应和酸雨), 也有害于人类健康。因此, 人类正面临着能源紧缺和环境污染的双重压力。为满足能源需求量日益增长和环境保护的需要, 我们必须寻找环保型的可再生能源来替代“化石能源” 以满足人类对能源的需求。 在各种可再生能源中氢能将有可能替代“化石能源”,成为未来能源利用的主要形式。氢能具有许多优点:①氢能燃烧时只生成水, 不产生任何污染物, 甚至连CO2也不会产生, 实现真正的“零污染” 和“零排放”;②氢能的能量密度高, 放热高达122 kJ/g, 是焦炭放热的4.5倍, 汽油的2.68倍;③氢能可经济有效的输送和储存, 可以利用已有的天然气管道输送, 输送成本低, 甚至优于输电, 因为输送氢能不会产生如电能输送过程中所产生的能量损耗;氢能的存储也比较简便, 其中储氢合金材料就是一种非常理想的储氢方法, 该方法储氢能力强、运输方便、操作容易, 且安全可靠。在利用储氢合金进行储氢时, 还可用以进行制冷或采暖(Kulkova et al., 2006), 因为储氢材料在吸氢时放热, 在放氢时吸热。正因为氢能具有如此多的优点, 许多大的跨国公司开始对制氢技术高度关注, 如主要汽车制造商(通用、福特、戴姆勒-克莱斯勒等)对开发以氢能作为燃料的汽车投入大量的人力和物力;宝马公司从20世纪70年代就开始研制以氢能为能源的汽车, 宝马公司现在已拥有了时速达240km的氢能汽车(Munro,2003)。同时, 一些发达国家的科研院所的科学家们对氢能的制备方法、制氢机制以及提高产氢量等进行了大量的研究。  相似文献   

中国近海肋脊螺科的研究Ⅰ     

张素萍 《海洋科学集刊》1997,(38):181-190

肋脊螺科(Costellariidae)属软体动物腹足纲、前鰓亚纲、新腹足目。以前本科动物大多被列入笔螺科(Mitridae)中的一个亚科,而目前已有一些学者(Cernohorsky,1978)，(Abbott & Dance,1983),( Springsteen & Leobrera,1986)根据它的齿舌和外部形态等特征将它分列为一个独立的科。本科动物在国内尚无人作过系统的研究,仅有一些零星报道。作者根据中国科学院海洋研究所历年调査搜集和全国海洋综合调查的标本,进行了整理、鉴定,初步鉴定出13个种,分隶于1属3亚属,其中6种在中国为首次报道。  相似文献   

Petroleum Migration Direction of the Silurian Paleo-pools in the Tarim Basin, Northwest China   总被引：1，自引：0，他引：1  

LIU Luofu  ZHAO Ye  HUO Hong  CHEN Lixin  CHEN Yuanzhuang  ZHAO Suping  LI Chao  LI Shuangwen  GUO Yongqiang  LI Yan 《《地质学报》英文版》2008,82(1):174-183

The results obtained in this paper indicate that carbazole-type compounds have high thermal stability and also show stability in oxidation and bio-degradation. This kind of compounds still has a high concentration and complete distribution in the analyzed dry asphalt samples, showing that they are particularly useful in studying petroleum migration of paleo-pool. During the basin＇s first-stage of oil-gas pool formation in the Silurian in Tazhong and Tabei areas of Tarim Basin （at the end of Silurian period） and the second-stage in the Awati area （in Permian）, the petroleum experienced a long-distance migration. During the formation of the Silurian paleo-pools in Tazhong Uplift at the end of Silurian, the petroleum mainly came from the lower and middle Cambrian source rocks in the Manjiaer sag. The petroleum migrated towards the southwest-south entering the Silurian reservoir beds in Tazhong first. Then, it further migrated within Silurian from northwest to southeast along the highs of the Structural Belts to the region of the Silurian pinchout boundary in Tazhong. In Tabei Uplift, during the first-stage of pool formation, the petroleum was also from the lower and middle Cambrian source rocks in the Manjiaer sag. It migrated northwest entering the Silurian reservoir beds in the Tabei Uplift firstly, and then the migration continued in the same direction within the Silurian reservoirs and finally the petroleum was trapped in higher positions. During the second-stage pool formation in the Silurian beds in the areas around Awati sag, the petroleum mainly came from the lower-middle Cambrian source rocks in the Awati sag. The petroleum migrated from the generation center to Silurian reservoirs in all directions around the sag through major paths, and the petroleum was finally trapped in higher locations.  相似文献   

Influence of sedimentary environments on mechanical properties of clastic rocks     

Zhaoping Meng  Jincai Zhang  Suping Peng 《Environmental Geology》2006,51(1):113-120

The sedimentary environments are the intrinsic factor controlling the mechanical properties of clastic rocks. Examining the relationship between rock sedimentary environments and rock mechanical properties gives a better understanding of rock deformation and failure mechanisms. In this study, more than 55 samples in coal measures were taken from seven different lithologic formations in eastern China. Using the optical microscope the sedimentary characteristics, such as components of clastic rocks and sizes of clastic grains were quantitatively tested and analyzed. The corresponding mechanical parameters were tested using the servo-controlled testing system. Different lithologic attributes in the sedimentary rocks sampled different stress–strain behaviors and failure characteristics under different confining pressures, mainly due to different compositions and textures. Results demonstrate that clastic rocks have the linear best-fit for Mohr-Coulomb failure criterion. The elastic moduli in clastic rocks are highly dependent upon confining pressures, unlike hard rocks. The envelope lines of the mechanical properties versus the contents of quartz, detritus of the grain diameter of more than 0.03 mm, and grain size in clastic rocks are given. The compressive strength or elastic modulus and the grain diameter have a non-monotonic relation and demonstrate the “grain-diameter softening” effect.  相似文献   

强震前大气层中温压相关特征的异常显示     

张慧  张苏平 《高原地震》1997,(3)

对中国大陆已发生的多次7级以上强震震中区气温、气压资料进行了研究，结果表明：在大震前（30天之内），气温－气压函数的平衡状态被破坏，其相关系数（代数值）不断增大，“正弓”形可作为短临异常的标志，同时对其成因也进行了初步探讨。  相似文献   

华北夏季旱涝的前期环流异常及其与北太平洋海温的关系   总被引：10，自引：1，他引：10  

朱平盛  张苏平 《应用气象学报》1997,8(4):437-444

文章分析了华北地区夏季旱涝的前期春季大气环流和北太平洋海温异常（ＳＳＴＡ）分布特征，探讨ＳＳＴＡ与异常环流的关系，并用ＯＳＵ－ＡＧＣＭ进行黑潮地区热源异常强迫的数值试验．结果表明，当春季北极低涡明显减弱，欧亚大陆中高纬度地区纬向环流加强，西太平洋副高位置偏北偏西，且存在负ＰＮＡ型异常环流时，华北地区夏季多雨涝；反之则少雨干旱．此时，西北太平洋和赤道东太平洋ＳＳＴ分别存在较大的正、负异常，它们与春季环流异常密切相关，黑潮区ＳＳＴＡ对北半球副热带及其以北的大气环流产生显著影响，正的ＳＳＴＡ是造成华北夏涝年的前期春季异常环流形势的重要因素．  相似文献   

阜新刘家区井田地质构造对煤储层影响及有利区块预测     

孟召平  杨锡禄 《中国煤田地质》1997,9(3):36-39

煤层气开发的有利区块研究重点是构造预测及评价，地质构造一方面决定或改变了煤层气的保存条件，另一方面改善了煤储层特性一本文以平均整旋角（θ）的梯度作为基本特征量，研究了井田构造变形转动场及其破坏规律，对井田煤层气赋存地质条件及开发有利区块进行了初步预测及评价。所得结论为本区煤层气开发布扎提供了科学依据。  相似文献   

用显微荧光和显微傅立叶红外光谱研究显微组分的热演化规律   总被引：4，自引：0，他引：4  

姚素平  金奎励 《沉积学报》1996,14(3):1-10

镜质体反射率是确定油源岩成熟度最广泛使用的参数，显微荧光强度及其变化也已成为检测烃源岩有机质生烃尤其是生油的标志之一，而红外光谱在研究生油母质干酪根的结构、类型和生烃潜力等方面均取得了大量的研究成果，特别是傅立叶红外显微镜的问世，给单显微组分提供了一种有效的研究手段。本文应用上述方法对一套人工熟化样品进行了检测和分析，探讨了显微组分的光性演变特征和化学成分的变化规律，并建立了显微组分的生油模式。  相似文献   

Organism relics or kerogens in oils as oil-source rock correlation indicator     

Suping Yao  Jingrong Zhang  Kuili Jin 《中国科学D辑(英文版)》1997,40(3):253-258

Organism relics or kerogens in oils are first obsenred by a confocal laser scanning microscope (CLSM) and a transmission electron microscope (TEM). The complexes of kerogens in oils are characterized by the presence of a great variety of microfossils or macerals. These kerogens in oils are mainly the residues of the original organic substances from which oil formed, and minor kerogens from enclosing rocks enter the oils, therefore, the components and types of the kerogens in crude oils can serve as an indirect indicator of oil-source rock correlation. This method was applied to Jurassic oils in the Junggar Basin and the Turpan-Hami Basin, and there are two types of the kerogens in oils: one containing a lot of macerals from terrestrial plants may derive from coals, and the other, characterized by a high content of microscopic algae, fungus spores and Acritarch, may originate from Permian organic matter. In addition, the reflectance of the vitrodetrinites in oils can be used as an indicator of oil-source rock correlation.  相似文献