Table 3. Optimum conditions of ZnO NPs biosynthesis by bacterium .
| Factors | Level | Contribution |
| A | 2 | 0.098 |
| B | 3 | 0.146 |
| C | 3 | 0.201 |
| Total contribution from all factors | - | 0.445 |
| Current grand average of performance | - | 0.416 |
| Expected result at optimum condition | - | 0.861 |