Enhancement of Thermal Stabilization of Formaldehyde Dehydrogenase fromPseudomonas putidaby Directed Evolution

We used directed evolution to enhance the thermostability of formaldehyde dehydrogenase from Pseudomonas putida. At 50 degrees C, the wild-type enzyme was inactivated within 30 min, but the variants obtained retained 80% activity for at least 300 min. At room temperature (30 degrees C), the variants obtained retained <80% activity for at least 500 h (21 d).