This paper presents a critical review of the literature on the application of genetically engineered microorganisms (GEMs) in bioremediation. The important aspects of using GEMs in bioremediation, such as development of novel strains with desirable properties through pathway construction and the modification of enzyme specificity and affinity, are discussed in detail. Particular attention is given to the genetic engineering of bacteria using bacterial hemoglobin (VHb) for the treatment of aromatic organic compounds under hypoxic conditions. The application of VHb technology may advance treatment of contaminated sites, where oxygen availability limits the growth of aerobic bioremediating bacteria, as well as the functioning of oxygenases required for mineralization of many organic pollutants. Despite the many advantages of GEMs, there are still concerns that their introduction into polluted sites to enhance bioremediation may have adverse environmental effects, such as gene transfer. The extent of horizontal gene transfer from GEMs in the environment, compared to that of native organisms including benefits regarding bacterial bioremediation that may occur as a result of such transfer, is discussed. Recent advances in tracking methods and containment strategies for GEMs, including several biological systems that have been developed to detect the fate of GEMs in the environment, are also summarized in this review. Critical research questions pertaining to the development and implementation of GEMs for enhanced bioremediation have been identified and posed for possible future research.

中文翻译：

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基因工程微生物（GEM）用于污染物的生物修复。

本文对基因改造微生物（GEM）在生物修复中的应用进行了文献综述。详细讨论了在生物修复中使用GEM的重要方面，例如通过途径构建以及具有酶特异性和亲和力修饰的新型菌株的开发。特别注意使用低氧条件下的细菌血红蛋白（VHb）处理芳香族有机化合物的细菌基因工程。VHb技术的应用可能会促进受污染场所的处理，在这些场所中，氧气的供应会限制需氧生物修复细菌的生长，以及许多有机污染物矿化所需的加氧酶的功能。尽管创业板有很多优势，人们仍然担心将其引入污染地点以增强生物修复可能会对环境造成不利影响，例如基因转移。讨论了与自然生物相比，环境中来自GEM的水平基因转移的程度，包括这种转移可能导致的细菌生物修复方面的益处。这篇综述还总结了GEM的追踪方法和遏制策略的最新进展，包括为检测环境中GEM的命运而开发的几种生物系统。已经确定了与开发和实施用于增强生物修复的GEM有关的关键研究问题，并提出了可能的未来研究。