TECHNOLOGY FOCUS - BIOLOGY - Preparation: No preparation method is given. Preferred Components: The polypeptide retains greater than 70% of the carbonic anhydrase activity when incubated for: 5 or more hours at a pH of 8.5-10.5, preferably 8.5-9.5; 3, 5, 10, 24 or more hours at a pH of 8.5-10.5; or 1-5, 10, 15, 24 or more hours at a pH of 8.5-10.5. The polypeptide retains at least 90% of the carbonic anhydrase activity when incubated for: 24 hours at 25 degrees C; 24 hours at 40 degrees C; or at least 10 hours, or at least 24 hours at 25 degrees C. The polypeptide retains at least 50% of the carbonic anhydrase activity when incubated for: 3 hours at 50 degrees C; 1-3 hours at 20-50 degrees C under high ionic strength conditions; 1 hour at 50 degrees C; 1-3 hours at 20 degrees C under high ionic strength conditions; at least 30 minutes, 1-3, 5, 10, 15, or 24 hours at 25 degrees C; at least 30 minutes, at least 1, at least 2, or at least 3 hours, or longer, at 20-50 degrees C under high ionic strength conditions; and 1-3, 5, 10, or 24 hours at 25 degrees C. The polypeptide retains at least 25% of the carbonic anhydrase activity when incubated for: 3 hours at 50 degrees C; 3 hours at 40 degrees C; 30 minutes, 1-5, 10, 15 or 24 hours at 40 degrees C; 30 minutes, 1, 2 or 3 hours at 50 degrees C; or 1-3 hours at 20-50 degrees C under high ionic strength conditions. The polypeptide retains greater than 25% of the carbonic anhydrase activity when incubated for: 30 minutes, 1-3, 5, 10, 24, or more hours at a pH of 8.5-10.5; or at least 30 minutes, at least 1 hour, at least 2 hours, at least 3 hours, or at least 5 hours at a pH of 8.5-10.5. The polypeptide retains at least 80% of the carbonic anhydrase activity when incubated for: 24 hours at 25 degrees C; or 24 hours at 40 degrees C. The polypeptide retains at least 40% of the carbonic anhydrase activity when incubated for: 3 hours at 50 degrees C; 2 hours at 50 degrees C; or 30 minutes, 1-3, 5, 10 or 24 hours at 40 degrees C. The polypeptide retains at least 20% of the carbonic anhydrase activity when incubated for: 3 hours at 50 degrees C; or 2 hours at 50 degrees C. The polypeptide retains greater than 60% of the carbonic anhydrase activity when incubated for 5 or more hours at a pH of 8.5-9.5. The polypeptide retains at least 60% of the carbonic anhydrase activity when incubated for: 24 hours at 40 degrees C; or 10 hours at 25 degrees C. The polypeptide retains at least 35% of the carbonic anhydrase activity when incubated for: 24 hours at 40 degrees C; 1, 2 or 3 hours at 50 degrees C; or 30 minutes, 1, 2 or 3 hours at 50 degrees C. The high ionic strength conditions comprise 1 M bicarbonate. The polypeptide has a melting temperature that is elevated in the presence of 1-2 M bicarbonate. The polypeptide has a higher thermostability and/or melting temperature at a higher ionic strength. The polypeptide comprises an amino acid sequence that is at least 75%, at least 80%, at least 90%, or at least 95% identical to the amino acid sequence of SEQ ID NO: 3, SEQ ID NO: 28, SEQ ID NO: 43, SEQ ID NO: 53, SEQ ID NO: 64, SEQ ID NO: 80, SEQ ID NO: 130, or SEQ ID NO: 136. The polypeptide is immobilized on a polymer, membrane, matrix, micellar material, wafer, solid support, or microparticle. The polypeptide further comprises a signal peptide sequence. The signal peptide sequence is SEQ ID NOs: 10-15 (comprising one of 6 (24-49) amino acid sequences fully defined in the specification), SEQ ID NOs: 69-73 (comprising one of 5 (27-30) amino acid sequences fully defined in the specification), SEQ ID NO: 81 (comprising a 27 amino acid sequence fully defined in the specification), SEQ ID NO: 82 (comprising a 26 amino acid sequence fully defined in the specification), SEQ ID NO: 83 (comprising a 32 amino acid sequence fully defined in the specification), SEQ ID NO: 131 (comprising a 26 amino acid sequence fully defined in the specification), and SEQ ID NO: 132 (comprising a 29 amino acid sequence fully defined in the specification). The host cell is a bacterial cell or fungal cell. EXAMPLE - No suitable example given.