TABLE 3.
Deteriogenic properties of fungi isolated from pPVC during the in situ triala
| Isolate | Identification | Esterase activity (REEb ml−1) | Biomass in DOA liquid medium (mg/40 ml) | Specific esterase activity (REE mg−1) | Growth on DOA agarc | Clearing on DOA agard | Growth on pPVCe | pPVC weight loss (%)f |
|---|---|---|---|---|---|---|---|---|
| MZ58 | Aureobasidium pullulans | 250 ± 40 | 11 ± 4.1 | 1500 ± 1300 | 1 | 3 | 1 | 3.7 ± 0.7 |
| MZ10 | Alternaria infectoria | 240 ± 17 | 12 ± 0.3 | 800 ± 75 | 3 | 3 | 2 | 3.9 ± 0.5 |
| MZ95 | Aspergillus niger | 190 ± 7 | 13 ± 2.8 | 630 ± 210 | 3 | 0 | 1 | 1.8 ± 0.2 |
| PRA FS8 | Aureobasidium pullulans | 160 ± 6 | 8.8 ± 1.5 | 760 ± 240 | 1 | 2 | 3 | 3.6 ± 0.7 |
| IMI70103 | Aureobasidium pullulans | 150 ± 16 | 5.2 ± 1.5 | 1300 ± 700 | 2 | 2 | 2 | 3.4 ± 0.7 |
| MZ107 | Phaeococcomyces sp. | 120 ± 4 | 6.9 ± 2.4 | 840 ± 370 | 0 | 0 | 3 | 4.0 ± 0.2 |
| MZ111 | Epicoccum nigrum | 100 ± 19 | 23 ± 4.2 | 180 ± 44 | 3 | 2 | 2 | 1.4 ± 0.3 |
| MZ7 | Alternaria alternata | 81 ± 10 | 17 ± 0.4 | 300 ± 120 | 3 | 3 | 2 | 4.1 ± 0.3 |
| MZ109 | Taphrina deformans | 68 ± 10 | 27 ± 9.6 | 160 ± 130 | 1 | 1 | 1 | 1.4 ± 0.4 |
| MZ113 | Kluyveromyces sp. | 51 ± 19 | 18 ± 12 | 260 ± 260 | 1 | 1 | 1 | 1.9 ± 0.7 |
| MZ115 | Cladosporium herbarum | 50 ± 21 | 14 ± 4.2 | 150 ± 78 | 3 | 0 | 3 | 1.7 ± 0.4 |
| MZ112 | Paecilomyces lilacinus | 27 ± 9 | 44 ± 7.0 | 26 ± 11 | 3 | 2 | 3 | 4.0 ± 1.5 |
| MZ108 | Kluyveromyces marxianus | 18 ± 6 | 25 ± 8.7 | 49 ± 51 | 0 | 0 | 0 | 1.8 ± 0.2 |
| MZ14 | Aspergillus ochraceus | 12 ± 5 | 17 ± 1.3 | 29 ± 8.4 | 3 | 2 | 1 | 3.9 ± 0.3 |
| MZ20 | Alternaria alternata | 11 ± 6 | 12 ± 2.3 | 27 ± 14 | 3 | 3 | 2 | 4.2 ± 1.2 |
| MZ104 | Penicillium glabrum | 5 ± 3 | 31 ± 5.3 | 8.1 ± 6.4 | 1 | 0 | 1 | 2.0 ± 0.4 |
| MZ8 | Thanatephorous cucumeris | 2 ± 1 | 11 ± 0.6 | 6.1 ± 2.3 | 2 | 2 | 0 | 1.7 ± 0.1 |
| MZ114 | Unidentified pink-red yeast | 0.4 ± 0.3 | 17 ± 3.6 | 1.3 ± 1.4 | 0 | 0 | 0 | 1.8 ± 0.4 |
| MZ103 | Emericella nidulans | 0.4 ± 0.3 | 7.3 ± 3.2 | 6.5 ± 8.3 | 1 | 1 | 1 | 6.8 ± 0.6 |
| MZ110 | Rhodotorula aurantiaca | 0.3 ± 0.4 | 16 ± 4.5 | 1.0 ± 1.5 | 0 | 0 | 0 | 1.9 ± 0.2 |
Test methods used were measurement of extracellular esterase activity and biomass production during growth using DOA as the sole carbon source, clear-zone production, growth on DOA agar, growth on pPVC, and pPVC weight loss. Isolates are ranked in order of decreasing extracellular esterase activity. Mean values ± 1 standard error of the mean are shown.
An REE is the enzyme activity that liberates 1 nmol of p-nitrophenol from PNB in 1 h at 25°C and at pH 5.5.
Scores for growth on DOA agar: 0, no visible growth; 1, slight growth within inoculation well; 2, colony diameter < 2 cm; 3, colony diameter ≥ 2 cm.
Scores for clear-zone production on DOA agar: 0, no clearing; 1, faint clearing below colony; 2, clearing extending beyond colony boundary; 3, intense clearing (agar completely transparent) extending beyond colony boundary.
Scores for growth on pPVC: 0, no visible growth; 1, slight growth, barely visible; 2, growth clearly visible around the edges of the PVC; 3, strong growth visible around the edges and in the agar above the pPVC.
The initial weight of individual pPVC pieces (100% weight loss value) ranged from 500 to 730 mg. The mean weight loss ± standard error of the mean from sterile pPVC controls was 0.1 ± 0.1%.