Effect of insertional mutations in the pueA and pueB genes encoding two polyurethanases in Pseudomonas chlororaphis contained within a gene cluster.

AIMS To better understand the role of PueA and PueB from Pseudomonas chlororaphis in polyurethane degradation, the present study was conducted to create insertional mutants in their respective genes. METHODS AND RESULTS Growth kinetic studies showed that the pueA knockout mutant had a greater effect than the pueB knockout mutant. The pueA mutant had an 80% decrease in cell density from that of the wild type, while the pueB mutant had an 18% decrease in cell density. Polyurethane utilization followed Michaelis-Menten kinetics. The pueA and pueB mutants exhibited a 17% and 10% decrease respectively in growth rate using polyurethane when compared with the wild type. CONCLUSIONS In this present study, pueA and pueB, are shown to be part of an ABC transporter gene cluster that consists of seven open reading frames. Mutational analysis results suggest that PueA may play a more major role in polyurethane degradation than PueB based on cell density and growth rates. SIGNIFICANCE AND IMPACT OF THE STUDY The results from this study provide a starting point for the eventual enhancement and bioremediation of polyurethane waste. Understanding the role of polyurethane-degrading enzymes is useful for the creation of strains for this purpose.