Background
To simplify the use of minimal medium for fed-batch fermentations, Scarab Genomics offers medium for both the batch phase and feeding phase of fed-batch fermentations. The Korz Feed Stock supplies glucose, magnesium, iron, and trace elements for the feeding stage of Modified Korz Medium fed-batch fermentations. Scarab’s Clean Genome® strains were specifically designed for the production of biotherapeutic protein and DNA. The “cleanest” medium to use for biotherapeutic production is a chemically defined, minimal medium. Accordingly, Modified Korz Minimal Medium has been extensively tested with the Scarab Clean Genome® Strains to verify its ability to support cell growth and the production of recombinant protein. Korz minimal medium is designed for high density fed-batch fermentation of E. coli (Korz et al. 1995, Sharma et al. 2007). The medium consists of phosphate buffer, magnesium, ferric citrate, trace elements, and uses glucose as the carbon source. The same base medium used for optimizing expression in shake flasks can also be used for fed-batch fermentation, thereby providing continuity between the two processes.
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Specifications
Kit Components Korz Feed Stock, 1000 ml Quality Control The media is confirmed for growth of Clean Genome® Strains using liquid culture and confirmed aseptic by no growth in liquid media and agar plates. Storage Conditions For long term storage, store the Korz Feed Stock at 4-12°C and protected from light. For short term storage the Feed Stock may be stored on the bench top at room temp for several days.
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Support
Product Manuals Korz Feed Stock, Sterile Papers
- Korz DJ, Rinas U, Hellmuth K, Sanders EA, Deckwer WD. J Biotechnol. 1995 Feb 21;39(1):59-65. Simple fed-batch technique for high cell density cultivation of Escherichia coli.
- Sharma S, Campbell JW, Frisch D, Blattner FR, Harcum SW. Biotechnol Bioeng. 2007 Dec 1;98(5):1056-70. Expression of Two Recombinant Chloramphenicol Acetyltransferase Variants in Highly Reduced Genome Escherichia coli Strains.
- Akesson M, Karlsson EN, Hagander P, Axelsson JP, Tocaj A. Biotechnol Bioeng. 1999 Sep 5;64(5):590-8. On-line detection of acetate formation in Escherichia coli cultures using dissolved oxygen responses to feed transients.
- DeLisa MP, Li J, Rao G, Weigand WA, Bentley WE. Biotechnol Bioeng. 1999 Oct 5;65(1):54-64. Monitoring GFP-operon fusion protein expression during high cell density cultivation of Escherichia coli using an on-line optical sensor.
- Pósfai G, et al., (2006) Emergent properties of reduced-genome Escherichia coli. Science 312:1044-6.
Patents & Disclaimers
Products are sold for non-commercial use only, under Scarab Genomics limited use label license: Limited Label Use.Scarab is providing you with this Material subject to the non-transferable right to use the subject amount of the Material for your research at your academic institution. The Recipient agrees not to sell or otherwise transfer this Material, or anything derived or produced from the Material to a third party. NO RIGHTS ARE PROVIDED TO USE THE MATERIAL OR ANYTHING DERIVED OR PRODUCED FROM THE MATERIAL FOR COMMERCIAL PURPOSES. If the Recipient makes any changes to the chromosome of the Material that results in an invention in breach of this limited license, then Scarab will have a worldwide, exclusive, royalty-free license to such invention whether patentable or not. If the Recipient is not willing to accept the terms of this limited license, Scarab is willing to accept return of this product with a full refund, minus shipping and handling costs. For information on obtaining a license to this Material for purposes other than research, please contact Scarab’s Licensing Department. Scarab Genomics’ technology is covered by U.S. Pat. No. 6,989,265 and related foreign applications. Clean Genome® is a registered trademark of Scarab Genomics, LLC.
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PH酸度计仪器的级别0.2级0.1级0.02级0.01级0.001级
分度值或最小显示值(pH)0.20.10.020.010.001
电计示值误差(pH)±0.1±0.05±0.01±0.01±0.002
配套测试示值总误差(pH)±0.2±0.1±0.02±0.02±0.01
注:配套测试时的测试范围应控制在pH3~pH10内。从上表可以看出,对于0.01级以下的酸度计,示值总误差数值等于其级别,对于0.01级的酸度计,示值总误差为0.02pH,对于0.001级酸度计,其示值总误差也只能达到±0.01pH,而且此时需要使用一级pH标准物质才能得到保证。(注意:pH国家标准物质分一级和二级两种,一般酸度计常用的是二级pH标准物质。)向左转|向右转
玻璃电极在初次使用前,必须在蒸馏水中浸泡一昼夜以上。
平时也应浸泡在蒸馏水中以备随时使用。玻璃电极不要与强吸水溶剂接触太久,在强碱溶液中使用应尽快操作,用毕立即用水洗净,玻璃电极球泡膜很薄,不能与玻璃杯及硬物相碰;玻璃膜沾上油污时,应先用酒精,再用四氯化碳或乙醚,最后用酒精浸泡,再用蒸馏水洗净。注意电极内要充满氯化钾溶液,应无气泡,防止断路。应有少许氯化钾结晶存在,以使溶液保持饱和状态,使用时拨去电极上顶端的橡皮塞,从毛细管中流出少量的氯化钾溶液,使测定结果可靠。
另外,pH测定的准确性取决于标准缓冲液的准确性。酸度计用的标准缓冲液,要求有较大的稳定性,较小的温度依赖性。
测定时把复合电极插在被测溶液中,由于被测溶液的酸度(氢离子浓度)不同而产生不同的电动势,将它通过直流放大器放大,最后由读数指示器(电压表)指出被测溶液的pH值。酸度计能在0~14pH值范围内使用。酸度计有台式、便携式、表型式等多种,读数指示器有数字式和指针式两种.
1、校正:先将仪器斜率调节器调节在100%位置,再根据被测溶液的温度,调节温度调节器到该温度值。
2、定位:把复合电极插入仪器,选择一种最接近样品pH值的缓冲溶液,把电极放入这一缓冲溶液里,摇动烧杯,使溶液均匀.待读数稳定后,该读数应是缓冲溶液的pH值,否则就要调节定位调节器。用于分析精度要求较高的测定时,要选择两种缓冲溶液(即被测样品的pH值在该两种缓冲溶液的pH值之间或接近)。待第种缓冲溶液的pH值读数稳定后,该读数应为该缓冲溶液的pH值,否则调节定位调节器。清洗电极,吸干电极球泡表面的余液。把电极放入第二种缓冲溶液中,摇动烧杯使溶液均匀,待读数稳定后,该读数应是第二种缓冲溶液的pH值,否则调节斜率调节器。
3、测量:经过pH标定的仪器,即可用来测定样品的pH值。这时温度调节器、定位调节器、斜率调节器都不能再动,用蒸馏水清洗电极,用滤纸吸干电极球部后。把电极插在盛有被测样品的烧杯内,轻轻摇动烧杯,待读数稳定后,就显示被测样品的pH值。复合电极的主要传感部分是电极的球泡,球泡极薄,千万不能跟硬物接触。测量完毕套上保护帽,帽内放少量补充液(3mol/L的氯化钾溶液),保持电极球泡湿润.仪器采用CMOS集成电路,不用时插入短路插头。检修时电烙铁要有良好的接地,以保护仪器。
按测量精度
可分0.2级、0.1级、0.01级或更高精度。
按仪器体积
分为笔式(迷你型)、便携式、台式还有在线连续监控测量的在线式。
根据使用的要求
笔式(迷你型)与便携式pH酸碱度计一般是检测人员带到现场检测使用。
选择pH酸碱度计的精度级别是根据用户测量所需的精度决定,而后根据用户方便使用而选择各式形状的pH计。
◆按便携性分的,分为:便携式pH计,台式pH计和笔式pH计。
◆按用途分为:实验室用pH计,工业在线pH计等。
◆按先进程度分为经济型pH计,智能型pH计,精密型pH计或分为指针式pH计,数显式pH计。
◆笔式pH计,一般制成单一量程,测量范围狭,为专用简便仪器。
便携式和台式pH计测量范围较广,常用仪器,不同点是便携式采用直流供电,可携带到现场。实验室pH计测量范围广、功能多、测量精度高。
工业用pH计的特点是要求稳定性好、工作可靠,有一定的测量精度、环境适应能力强、抗干扰能力强,具有模拟里量输出、数字通讯、上下限报警和控制功能等。向左转|向右转
现代酸度计具有:结构简单,操作方便,测量准确和自动化程度高的优点。

