TABLE 2.
Characterization of constructed metagenomic libraries and screening of these libraries for genes conferring proteolytic activity on E. colia
| Library | Sample site | Vector | No. of insert-containing E. coli clones | Avg insert size (kb)b | Estimated library size (Mb) | No. of proteolytic E. coli clones with a stable phenotype (designation) |
|---|---|---|---|---|---|---|
| SK1 | Mixed sample A | pSKII+ | 52,000 | 4.2 | 218 | 0 |
| CR1 | Mixed sample A | pCR2.1 | 78,000 | 5.3 | 413 | 1 (pTW1) |
| SK2 | Mixed sample B | pSKII+ | 55,000 | 3.9 | 215 | 2 (pTW2, pTW3) |
| CR2 | Mixed sample B | pCR2.1 | 65,000 | 4.0 | 260 | 0 |
| SK3 | Mining shaft | pSKII+ | 10,000 | 3.9 | 39 | 0 |
| CR3 | Mining shaft | pCR2.1 | 37,000 | 4.6 | 170 | 1 (pTW4) |
| SK4 | Compost soil | pSKII+ | 32,000 | 2.4 | 77 | 0 |
| CR4 | Compost soil | pCR2.1 | 60,000 | 3.5 | 210 | 0 |
a
In each case, 5 μg of isolated metagenomic DNA was used as starting material for library construction. Approximately 10,000 E. coli clones of each library were screened.
b
The average insert size was determined by analysis of 50 insert-containing recombinant plasmids.