Table 4.
Effect of reaction temperature on the conversion of valeric acid to ethyl valerate and specific activity of biocatalysts after esterification.
| Acid-to-Alcohol Ratio | Conversion to Ethyl Valerate (mol %) | * Specific Activity (U/gbiocatalyst) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 50 °C | 45 °C | 40 °C | 35 °C | 30 °C | 25 °C | 20 °C | 50 °C | 40 °C | 30 °C | 20 °C | |
| 1:3 | 84 | 86 | 94 | 88 | 80 | 82 | 83 | 234 ± 11 | 485 ± 17 | 623 ± 14 | 630 ± 13 |
| 1:2 | 85 | 87 | 96 | 91 | 84 | 84 | 87 | ||||
| 1:1 | 74 | 78 | 76 | 71 | 75 | 71 | 75 | ||||
Conditions for esterification reaction: 12% m/v of biosilicified enzyme, 1000 rpm, 2 h CH in batch reactor. * To determine the influence of temperature on the specific activity of the catalyst, 12% m/v of biosilified enzyme was incubated in DW, 1000 rpm, 2 h CH in batch reactor at the different temperatures.