• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Applied and Environmental Microbiology >Reduction of Cell Lysate Viscosity during Processing of Poly(3-Hydroxyalkanoates) by Chromosomal Integration of the Staphylococcal Nuclease Gene in Pseudomonas putida
【24h】

Reduction of Cell Lysate Viscosity during Processing of Poly(3-Hydroxyalkanoates) by Chromosomal Integration of the Staphylococcal Nuclease Gene in Pseudomonas putida

机译：通过恶臭假单胞菌中葡萄球菌核酸酶基因的染色体整合降低聚3-羟基链烷酸酯加工过程中细胞裂解液的粘度

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Poly(3-hydroxyalkanoates) (PHAs) are biodegradable thermoplastics which are accumulated by many bacterial species in the form of intracellular granules and which are thought to serve as reserves of carbon and energy. Pseudomonas putida accumulates a polyester, composed of medium-side-chain 3-hydroxyalkanoic acids, which has excellent film-forming properties. Industrial processing of PHA involves purification of the PHA granules from high-cell-density cultures. After the fermentation process, cells are lysed by homogenization and PHA granules are purified by chemical treatment and repeated washings to yield a PHA latex. Unfortunately, the liberation of chromosomal DNA during lysis causes a dramatic increase in viscosity, which is problematic in the subsequent purification steps. Reduction of the viscosity is generally achieved by the supplementation of commercially available nuclease preparations or by heat treatment; however, both procedures add substantial costs to the process. As a solution to this problem, a nuclease-encoding gene fromStaphylococcus aureus was integrated into the genomes of several PHA producers. Staphylococcal nuclease is readily expressed in PHA-producing Pseudomonas strains and is directed to the periplasm, and occasionally to the culture medium, without affecting PHA production or strain stability. During downstream processing, the viscosity of the lysate from a nuclease-integratedPseudomonas strain was reduced to a level similar to that observed for the wild-type strain after treatment with commercial nuclease. The nuclease gene was also functionally integrated into the chromosomes of other PHA producers, including Ralstonia eutropha.
机译：聚（3-羟基链烷酸酯）（PHA）是可生物降解的热塑性塑料，它被许多细菌以细胞内颗粒的形式积累，被认为是碳和能量的储备。恶臭假单胞菌（Pseudomonas putida）积累由具有优异成膜性能的中侧链3-羟基链烷酸组成的聚酯。 PHA的工业加工涉及从高细胞密度培养物中纯化PHA颗粒。发酵过程后，通过均质裂解细胞，并通过化学处理和反复洗涤纯化PHA颗粒，以生产PHA胶乳。不幸的是，裂解过程中染色体DNA的释放导致粘度急剧增加，这在随后的纯化步骤中是有问题的。通常通过补充市售的核酸酶制剂或通过热处理来降低粘度。但是，这两个过程都会增加大量成本。为了解决这个问题，将金黄色葡萄球菌的核酸酶编码基因整合到了多个PHA生产者的基因组中。葡萄球菌核酸酶很容易在产生PHA的假单胞菌菌株中表达，并且直接针对周质，偶尔针对培养基，而不会影响PHA的产生或菌株稳定性。在下游加工期间，来自核酸酶整合的假单胞菌菌株的裂解物的粘度降低到类似于用商业核酸酶处理后的野生型菌株观察到的水平。核酸酶基因也被功能整合到其他PHA生产者的染色体中，包括富营养的Ralstonia。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号