Research Article
Optimization of Fermentation Conditions and Media for Production of Glucose Isomerase from Bacillus megaterium Using Response Surface Methodology
Table 2
Experimental variables at different levels and their impacts on glucose isomerase production in Plackett–Burman experimental design matrix.
| Factors | Levels | Impact levels | Symbols | Variables | Low (−1) | High (+1) | Impact | Prob > F value |
| X1 | D-xylose concentration (%) | 0.5 | 1.5 | 0.019b | 0.014 | X2 | K2HPO4 concentration (%) | 0.1 | 0.3 | −0.004a | 0.194 | X3 | MgSO4 concentration (%) | 0.05 | 0.15 | 0.002a | 0.382 | X4 | Yeast extract concentration (%) | 0.75 | 1.25 | 0.02b | 0.012 | X5 | Peptone concentration (%) | 0.5 | 1.5 | 0.005a | 0.157 | X6 | pH | 6.5 | 7.5 | −0.002a | 0.536 | X7 | Bacterial inoculum size (%) | 15 | 25 | 0.002a | 0.501 | X8 | Cultivation temperature (oC) | 35 | 39 | −0.002b | 0.011 | X9 | Rotation rate (rpm) | 100 | 140 | 0.008a | 0.071 |
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The letter “a” indicates no significant impact with 95% confidence level; the letter “b” indicates significant impact with 95% confidence level. |