Targeted environmental genomics for biocatalyst discovery

微生物界蕴藏着丰富的DNA序列信息，可以用来生产生物产品和酶，介导工业相关的化学反应。在某些情况下，由这些基因产物编码的生物过程可以产生高能有机化合物，可能开始直接取代对环境有害的基于化石燃料的技术。多年来，由于无法培养微生物群落中存在的大多数微生物，因此无法获得微生物世界中全部丰富的遗传物质。分子技术现在提供了从这些未培养的微生物中获取DNA的方法；现在有可能从直接从少量土壤中提取的DNA中构建基因库，这些基因库代表了土壤样本中存在的每种微生物的遗传物质。这种捕获的环境DNA（“宏基因组”）被寄主在容易培养的细菌中，捕获的基因的相应表达可以被检测和筛选，以寻找目标基因产物的表达。通过这种方式，可以在没有培养的前提下，从未培养的微生物中开发出具有所需功能的多样化和新颖基因。该提案描述了加拿大MetaMicroBiome计划的建立，这是一个代表加拿大土壤微生物群落的环境DNA图书馆的公开收集。来自不同的加拿大生物群落的土壤样本将被选择，因为它们无与伦比的微生物多样性和相应的代谢丰富度。这些DNA文库将通过强大的DNA测序技术来确定每个样品的微生物群落多样性。在与Iogen公司的合作中，我们将通过分离新的基因，将木质纤维素生物质转化为生物燃料和生物产品应用，来证明这些环境文库中有令人感兴趣的DNA。酶活性和结构的详细表征将有助于开发或改进生产高附加值化学品的工艺。

The microbial world harbours a wealth of DNA sequence information that can be harnessed for the production of bioproducts and enzymes that mediate industrially relevant chemical reactions. In some cases, the biological processes encoded by these gene products can produce high-energy organic compounds that may begin to directly replace fossil fuel-based technologies that are harmful to the environment. For many years, access to the full richness of the genetic material in the microbial world has been hampered by the inability to cultivate most microbes present in microbial communities. Molecular techniques now provide the methods to access the DNA from this uncultivated microbial majority; it is now possible to construct gene libraries from DNA that is extracted directly from a handful of soil, and these libraries then represent the genetic material from each of the microorganisms present in that soil sample. This captured environmental DNA (the 'metagenome') is hosted in readily cultivated bacteria and the corresponding expression of captured genes can be detected and screened for the expression of targeted gene products. In this way, diverse and novel genes from uncultivated microorganisms that carry out desired functions may be exploited, without the prerequisite of cultivation. This proposal describes the establishment of the Canadian MetaMicroBiome Initiative, a publicly accessible collection of libraries of environmental DNA representing Canadian soil microbial communities. Soil samples from disparate Canadian biomes will be chosen due to their unparalleled microbial diversity and corresponding metabolic richness. These DNA libraries will be characterized by powerful DNA sequencing techniques to determine the microbial community diversity of each sample. In partnership with Iogen Corp., we will show that there is DNA of interest in these environmental libraries by isolating new genes for the conversion of lignocellulosic biomass for biofuel and bioproducts applications. Detailed characterization of the enzyme activities and structures will aid in the development or improvement of processes for the production of high value-added chemicals.