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   

THE TEMPORAL AND SPATIAL DISTRIBUTION OF SEA SURFACE WIND ALONG THE COAST OF GUANGDONG PROVINCE IN CHINA     

廖菲  邓华  陈柏纬 《热带气象学报(英文版)》2019,25(1):129-140

Temporal and spatial distribution characteristics of sea surface wind in Guangdong''s coastal areas were analyzed with data from four offshore observational stations between 2012 and 2015. The results are shown as follows: (1) The probability distribution of wind speed was basically consistent with Gaussian distribution characteristics; winds of Beaufort force 6 or higher were observed mainly in far offshore stations from October to March. (2) The probability distribution of wind direction was represented well by Weibull distribution. The deviation of wind direction of far station was relatively small for it was mainly controlled by monsoon over the South China Sea, while the near offshore station had a relatively large diurnal variation because of the influence of local synoptic systems such as sea-land breeze. (3) There were significant seasonal differences in wind speed and direction observed by different offshore observational stations. In strong wind seasons, the deviation of wind direction was relatively small while the deviation of wind speed was relatively large, and vice versa. In contrast with Class I station, the other three stations exhibited approximately normal distribution of wind direction and wind speed deviations. (4) Wind direction diurnal variation was moderate in windy periods, while it was obvious in relatively lower speed conditions. The deviation of wind speed in windy periods was generally greater because it was influenced by mesoscale weather systems for 10-20 h, and the influence was complicated, resulting in greater local differences in wind speed.  相似文献   

Aircraft vertical profiling of variation of CO₂ over a Canadian Boreal Forest Site: a role of advection in the changes in the atmospheric boundary layer CO₂ content     

ALEXANDER SHASHKOV  KAZ HIGUCHI  DOUGLAS CHAN 《Tellus. Series B, Chemical and physical meteorology》2007,59(2):234-243

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产酯酶海洋中度嗜盐菌Halomonas sp.LYG1-1的分离鉴定及其酶学性质          下载免费PDF全文

王昭凯  易志伟  刘洋  产竹华  曾润颖 《热带海洋学报》2014,33(1):69-73

以从海南三亚近海海水中采集的样品为研究对象,利用平板筛选法筛到一株产酯酶的中度嗜盐菌菌株LYG1-1。通过形态学、生理生化及16S rRNA序列分析,发现该菌株为革兰氏阴性菌,其最适生长温度为30℃,最适生长pH为7.5,最适NaCl浓度为10%。16S rRNA基因序列分析显示,菌株LYG1-1与Halomonas salina亲缘性最近,16S rRNA基因序列相似性为99.72%。在含10%NaCl的0.05mol·L-1Tris-HCl(pH 8.0)缓冲液中,45℃条件下作用,酶活性最高,40℃处理24h仍保持83%的活性。金属离子浓度为5mmol·L-1时,Ca2+、Mg2+对菌株LYG1-1酶活具有明显的激活作用,Hg2+表现出强烈的抑制作用。  相似文献   

面向交通土建工程的网络化移动勘测办公系统     

乐亚南  杨建中  张献州  黄惠峰  产光杰  莫春 《测绘工程》2014,23(11)

现今的交通土建类大型工程项目数据繁冗复杂。传统的数据处理方式速度慢、精度低,已不能满足大型工程管理的需要。GeoNMOS软件可弥补在大型工程项目中数据处理方面的不足。文中提出网络化移动勘测办公系统的设计理念,着重分析GeoNMOS各个模块的特点及其主要功能。  相似文献   

城区水文循环机制与改善策略分析          下载免费PDF全文

廖朝轩  詹丽梅  陈家梁  邱奕儒 《水科学进展》2008,19(1):49-53

在城区化过程中,由于人口快速成长且集中,随之而来的建筑物、道路等不透水面密度增加,导致地下水补给减少及破坏水文循环。为了解土地利用方式改变对长期水文量影响,建立一个适宜的城区水循环模式是非常重要的。选定台湾台北的六馆抽水站集水区进行分析,模式参数经过敏感度分析、率定与验证。采用改变不同透水铺面设置比例的方案,评估其对径流量、入渗量、蒸发散量的改变。并分析设置不同比例屋顶雨水贮集系统对地表径流量及供水量的改变。所建立的城区水循环模式是评估土地利用改变造成水文量的改变的一个有效工具,并可提供决策者做为城区土地利用决策的参考。  相似文献   

Microphysical Characteristics of Extreme-Rainfall Convection over the Pearl River Delta Region,South China from Polarimetric Radar Data during the Pre-summer Rainy Season     

Hao HUANG  Kun ZHAO  Johnny C.L.CHAN  Dongming HU 《大气科学进展》2023,40(5):874-886

During the pre-summer rainy season, heavy rainfall occurs frequently in South China. Based on polarimetric radar observations, the microphysical characteristics and processes of convective features associated with extreme rainfall rates(ERCFs) are examined. In the regions with high ERCF occurrence frequency, sub-regional differences are found in the lightning flash rate(LFR) distributions. In the region with higher LFRs, the ERCFs have larger volumes of high reflectivity factor above the freezin...  相似文献   

Effects of Dropsonde Data in Field Campaigns on Forecasts of Tropical Cyclones over the Western North Pacific in 2020 and the Role of CNOP Sensitivity     

Xiaohao QIN  Wansuo DUAN  Pak-Wai CHAN  Boyu CHEN  Kang-Ning HUANG 《大气科学进展》2023,40(5):791-803

Valuable dropsonde data were obtained from multiple field campaigns targeting tropical cyclones, namely Higos,Nangka, Saudel, and Atsani, over the western North Pacific by the Hong Kong Observatory and Taiwan Central Weather Bureau in 2020. The conditional nonlinear optimal perturbation(CNOP) method has been utilized in real-time to identify the sensitive regions for targeting observations adhering to the procedure of real-time field campaigns for the first time. The observing system experiments...  相似文献   

香港世界地质公园晚侏罗世荔枝庄组岩石组合及其成岩地质过程解析     

姜杨  杨家明  杨祝良  沈加林  马雪  陈羽岚  钱迈平  邢光福  余明刚  段政 《地质论评》2016,62(3):759-769

中国东南大陆晚侏罗世地层普遍缺失,仅零星见于个别地区,香港新界东北的荔枝庄组即为其一。荔枝庄组出露于香港世界地质公园沉积岩园区的荔枝庄地区,自下往上由火山岩—沉积岩—火山岩组合而成,沉积岩中发育大型包卷层理和滑塌构造等典型沉积构造,是香港地区最具代表性的晚侏罗世火山—沉积岩系。通过实测地层剖面研究,确定其成岩过程大体上可划分为早期普林尼式火山爆发、中期破火山口湖相沉积和晚期普林尼式火山爆发三个阶段,以湖相沉积作用为主、火山喷发作用为辅;受晚期火山岩浆活动的影响,沉积岩层普遍发生硅化或炭化。荔枝庄组独特的岩石组合与形成的古地理环境,为探讨中国东南大陆中生代火山活动—沉积作用方式与成岩过程,提供了难得的研究实例。  相似文献   

大庆油田葡萄花油层组储层非均质性主控因素分析   总被引：6，自引：0，他引：6       下载免费PDF全文

单敬福  纪友亮 《沉积与特提斯地质》2006,26(4):95-100

本文对萨尔图油田中部葡萄花油层组的非均质性进行定量半定量研究,认为葡萄花油层组PⅠ2小层层内非均质性最严重,与沉积微相密切相关;单砂层垂向上渗透率的变化以正韵律和复合式韵律为主,局部发育反韵律模式;层内非均质性强弱依次为PⅠ2a、PⅠ3、PⅠ2b、PⅠ1、PⅠ4;层间非均质性在PⅠ3和PⅠ4间表现得最强,其它相对要弱;各小层平面非均质性相差无几,整体表现为较强的非均质性。  相似文献