| Popis: |
An economical preparation of α-amylase is obtained from a high yielding stable mutant of Bacillus subtilis by qualitative and quantitative optimization of the ingredients of its production medium as well as production parameters. Further, it is upgraded by filtration and 15-fold concentration through an ultrafiltration membrane. Finally, its stabilization during storage at ambient temperature is attained by using 20% (w/v) sodium chloride and 0.1% (w/v) calcium chloride as stabilizers. While the concentrated preparation without stabilizer showed less than 5% of the original activity after 26 weeks of storage at ambient temperature, the concentrated preparation, fortified with 20% (w/v) sodium chloride and 0.1% (w/v) calcium chloride, showed 63% stabilization during the same period under identical conditions of storage. This stabilizer could be substituted by maintenance at 10°C for comparable stabilization of concentrated α-amylase preparation for 26 weeks. The stabilized enzyme preparation afforded efficient liquefaction (DE 16–20%) of 35% (w/w) tapioca starch at 76°C in 30 min, comparable to the fresh preparation with or without concentration. The above process protocol has cumulatively provided an economical, upgraded, stabilized and efficient alternative to commercially available α-amylase preparations. |
