Metagenomic Approaches for Understanding New Concepts in Microbial Science

Table 1

Genes discovered through metagenomic approaches with high biotechnological potential.

Function/gene target	DNA source	Library size	Screening method	Number of hits found	Biotechnological relevance	Reference
Enzymes
Esterases, endo-β-1,4-glucanases, and cyclodextrinase	Cow rumen	1.1 Gb	Function based	22	Eight enzymes (36%) were entirely new	[112]
Laccase	Water from South China Sea	1.4 Gb	Sequencing based	1	High chloride resistance and ability to decolorize industrial dyes	[136]
Naphthalene dioxygenase	Oil-contaminated soil	294 Mb	Function based	2	Applicable in oil-contaminated soil/water	[137]
Oxygenases	Artificially polluted soil	5.2 Gb	Function based	29	Applicable in oil-contaminated soil/water	[126]
Cutinases	Leaf-branch compost	735 Mb	Function based	19	Potential application in polyethylene terephthalate (PET) degradation	[138]
Phenol hydroxylases and catechol 2,3-dioxygenases	Wastewater treatment plant	495 Mb	Function based	413	Potential use in aromatic compound degradation	[139]
Carboxylesterase	Marine water	~1.3 Gb	Function based	95	Cold-active and salt-resistant enzyme	[140]
Cellulase/esterase	Water lakes	1.86 Gb	Function based	3	New cellulase	[141]
Cellulase	Soil	Not found	Function based	1	Halo- and thermotolerant enzyme	[142]
β-Glucosidase	Hydrothermal spring water	Not found	Function based	1	Thermotolerant and heath-active enzyme	[143]
Lipase/protease/hemolysins/biosurfactants	Slaughterhouse drain	~884 Mb	Function based	22	Antimicrobial activity	[144]
Genes that confer resistance to extreme conditions
Acid resistance genes	Plankton and rhizosphere from Tinto River	~2.3 Gb	Function based	15	Genes involved in acid resistance	[118]
Nickel resistance genes	Rhizosphere of E. andevalensis from Tinto River	2.15 Gb	Function based	13	Genes related to nickel resistance	[117]
Salt resistance genes	Brine and rhizosphere from Es Trenc saltern	2.15 Gb	function-based	11	Genes conferring salt resistance	[116]
Arsenic resistance genes	Headwater from Tinto River	151 Mb	Function based	18	Genes involved in arsenic resistance	[145]
Regulatory sequences
Constitutive promoters	Soil from secondary Atlantic Forest	~500 Mb	Function based	33	Use as “biobricks”	[135]
Pathways/systems/operons
Naphthalene-degrading system	Naphthalene-contaminated groundwater	~283 Mb	Sequencing based	3	Pollutant-degrading enzyme systems	[146]
Dioxygenase-degrading cluster	Forest soil	260–815 bp	Sequencing based	11	Degrading phenoxyalkanoic acid (PAA) herbicides avoiding groundwater contamination	[147]
NRPS biosynthetic pathway	Tunicate consortium in Florida Keys	~280 Mb	Sequencing based	1	ET-743 biosynthetic pathway; anticancer molecule	[148]
Bioactive molecules
Pigmentation producing and antibacterial activity	Soil	Not found	Function based	45	Potential new molecules to be used as antibiotics	[125]
Turbomycin A and B	Soil	~1 Gb	Function based	3	Antibiotic activity	[16]
Antimicrobial small molecules	Soil	~720 Mb	Function based	4	Antibiotic activity	[149]

All genes discovered through sequencing-based methodologies were experimentally tested for their related functions.