Purification and characterization of fungal poly(3-hydroxybutyrate) depolymerase from Paecilomyces lilacinus F4-5 and enzymatic degradation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) film

Poly(3-hydroxybutyrate) [P(3HB)] depolymerase was purified from a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)]-degrading fungus, Paecilomyces lilacinus F4-5 by hydrophobic and ion exchange column chromatography, and showed a molecular mass of 45 kDa. The optimum temperature and pH of the P(3HB) depolymerase were 50 degrees C and 7.0, respectively. The enzyme was stable for at least 30 min at temperatures below 40 degrees C, while the activity abruptly decreased over 55 degrees C. Enzymatic P(3HB-co-3HV) degradation showed a similar degradation pattern to that of film overlaid by fungal hyphae. It reflects that the fungal degradation of P(3HB-co-3HV) in soil is mainly caused by extracellular depolymerases.