Table 1.
Enzyme activities of four PGPB strains
| Strain | ACC deaminase (nmol AKB mg−1 cell h−1) | β-1,3-glucanase (U mL−1) | Cellulase (mm dia.) | Protease (mm dia.) | Chitinase | Lipase |
|---|---|---|---|---|---|---|
| Sphingomonas sp. T168 | 421.84±9.84a | 0.15±0.01a | 0.00±0.00a | 0.00±0.00a | − | − |
| Streptomyces sp. R170 | 690.60±10.36d | 0.21±0.01b | 2.26±0.08c | 0.18±0.01b | − | + |
| Streptomyces sp. R181 | 494.02±12.54b | 0.20±0.01b | 1.58±0.08b | 1.07±0.05d | − | − |
| Methylibium sp. R182 | 638.68±17.00c | 0.42±0.01c | 3.88±0.19d | 0.48±0.02c | + | − |
Values are means±SD. A one-way ANOVA was performed to compare the significance of differences between means. Mean values in the same column with common superscript letters are not significantly different from each other (p≤0.05) according to Tukey’s HSD test. AKB: α-ketobutyrate. Chitinase and lipase are presented with + or − to indicate the presence or absence of activity, respectively. Regarding β-1,3-glucanase activity (U), one unit is defined as the amount of enzyme that liberated one μmol of glucose h−1 under the defined conditions.