Metagenomic library

Functional screening of a soil metagenomic library for cellulases revealed a total of eight cellulolytic clones, one of which was purified and characterized [58]. Despite the fact that this library had been generated from a soil sample collected from a... 

Metagenomics has been applied to the search for novel genes encoding the synthesis of vitamins such as biotin and vitamin C [47,76]. Seven cosmids were detected in metagenomic libraries obtained after avidin enrichment of environmental samples. The highest levels of biotin production in this study were detected in a cosmid... 

An effective and generic method of screening of BVMO activity is indispensable for screening metagenome libraries as these libraries are often in the range of 100000-1000000 clones. Therefore, it is a challenge to develop a novel way to efficiently detect BVMO activity in gene libraries. This would facilitate... 

Rhee J-K, D-G Ahn, Y-G Kim, J-W Oh (2005) New thermophilic and thermostable esterase with sequence similarity to the hormone-sensitive lipase family cloned from a metagenomic library. Appl Environ Microbiol 71 817-825. 

But there is still another point, not yet discussed but with considerable potential, which may also impact eventually on technical asymmetric catalysis. Even though biocatalysts are efficient, active, and selective, there still remains one big disadvantage At present, there is not yet an appropriate enzyme known or available for every given chemical reaction. It is estimated that about 25 000 enzymes exist in Nature, and 90% of these have still to be discovered [28, 29]. New biocatalysts are made available nowadays not only from screening known organism but also via screening metagenomic libraries and directed evolution techniques [30]. 

Cottrell, M. T., Yu, L. Y., and Kirchman, D. L. (2005). Sequence and expression analyses of Cytophaga-like hydrolases in a Western arctic metagenomic library and the Sargasso seat. Appl. Environ. Microbiol 71, 8506—8513. 

Molecules and Their Biosynthetic Genes Isolated from Metagenomic Libraries 461... 

A number of metagenomic libraries hosted in E. coli have now been screened for clones that produce either antibacterial activities or color. In addition to hits that are unique to each library, these studies have encountered four common hits. These include the antibacterially active long-chain A-acyl amino acid-producing clones described earlier in this section, red antibacterially active clones that express aminolevulinic acid synthases (hemA), brown clones that produce melanin-like polymers, and blue clones that produce mixtures of indigo (25) and indinibin... 

In search of alternative thiamine pathways that might be more susceptible to metabolic pathway engineering, metagenomic libraries from various habitats were screened using a thiamine auxotrophic, tAiC-deleted E. coli screening host. In addition, the host contained a deletion in an early pur gene to prevent the supply of AIR, the ThiC substrate, to remove those clones which are complemented by the conventional ThiC dependent pathway. None of the hits encoded a genuinely novel thiamine pathway (BRAIN AG, unpublished). 

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