title: Degradation of polyester polyurethane by a newly isolated soil bacterium, Bacillus subtilis strain MZA-75.
abstract: A polyurethane (PU) degrading bacterial strain MZA-75 was isolated from soil through enrichment technique. The bacterium was identified through 16S rRNA gene sequencing, the phylogenetic analysis indicated the strain MZA-75 belonged to genus Bacillus having maximum similarity with Bacillus subtilis strain JBE0016. The degradation of PU films by strain MZA-75 in mineral salt medium (MSM) was analyzed by scanning electron microscopy (SEM), fourier transform infra-red spectroscopy (FT-IR) and gel permeation chromatography (GPC). SEM revealed the appearance of widespread cracks on the surface. FTIR spectrum showed decrease in ester functional group. Increase in polydispersity index was observed in GPC, which indicates chain scission as a result of microbial treatment. CO2 evolution and cell growth increased when PU was used as carbon source in MSM in Sturm test. Increase in both cell associated and extracellular esterases was observed in the presence of PU indicated by p-Nitrophenyl acetate (pNPA) hydrolysis assay. Analysis of cell free supernatant by gas chromatography-mass spectrometry (GC-MS) revealed that 1,4-butanediol and adipic acid monomers were produced. Bacillus subtilis strain MZA-75 can degrade the soft segment of polyester polyurethane, unfortunately no information about the fate of hard segment could be obtained. Growth of strain MZA-75 in the presence of these metabolites indicated mineralization of ester hydrolysis products into CO2 and H2O.
authors.affiliation: Department of Microbiology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan.
authors.forename: Ziaullah
authors.initials: Z
authors.lastname: Shah
authors.forename: Lee
authors.initials: L
authors.lastname: Krumholz
authors.forename: Deniz Fulya
authors.initials: DF
authors.lastname: Aktas
authors.forename: Fariha
authors.initials: F
authors.lastname: Hasan
authors.forename: Mutiullah
authors.initials: M
authors.lastname: Khattak
authors.forename: Aamer Ali
authors.initials: AA
authors.lastname: Shah
mesh_terms: D000272:Adipates / Q000494:pharmacology; D001412:Bacillus subtilis / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism* / Q000648:ultrastructure; D001673:Biodegradation, Environmental / Q000187:drug effects; D002072:Butylene Glycols / Q000494:pharmacology; D002245:Carbon Dioxide / Q000378:metabolism; D002850:Chromatography, Gel; D004950:Esterases / Q000096:biosynthesis; D005110:Extracellular Space / Q000201:enzymology; D008401:Gas Chromatography-Mass Spectrometry; D008969:Molecular Sequence Data; D010802:Phylogeny; D011091:Polyesters / Q000378:metabolism*; D011140:Polyurethanes / Q000378:metabolism*; D012988:Soil Microbiology; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000272:Adipates; D002072:Butylene Glycols; D011091:Polyesters; D011140:Polyurethanes; D002245:Carbon Dioxide; C029900:adipic acid; C039681:1,4-butanediol; D004950:Esterases