Biodegradation Of Polyurethanes Research Articles

Design of Biodegradable PU Textile Coating.

Polyurethane (PU) coatings are used in diverse applications such as textile coating. Up to today, landfilling is still the most occurring way of processing PU waste. Biodegradation is an alternative route for processing PU waste and decreases the amount of microplastics in the case of landfilling. In this study, a biodegradable PU textile coating was developed. The PU was characterized via Fourier-transformed infrared (FT-IR) thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The PU was thermoplastic and had a melting point of approximately 33 °C. The performance of the coating was studied by assessing the water barrier and mechanical properties. The PU coating completely disintegrated, and the biodegradation of PU was assessed in soil and was almost 60%. Furthermore, the plant toxicity was examined by evaluating seedling emergence and growth.

Biodegradation of Polyurethane by Fungi Isolated from Industrial Wastewater-A Sustainable Approach to Plastic Waste Management.

Polyurethane (PU) is a type of polymer, which exists in various forms in the environment. Very few studies are available concerning the structure or enzymatic mechanism of the microbial community, which can degrade PU. Degradation of PU remains a difficult problem with respect to the environmental and biological disciplines. This study mainly focused on identifying the micro-organisms able to degrade polyurethane and confirming the degradation by performing a plate assay, Sturm test and scanning electron microscopy. Optimal culture conditions for maximum PU degradation were also analyzed through classical methods. A soil burial test was conducted by placing polyurethane films in the soil for one month, and the microbe growing on the surface of polyurethane films-with a maximum degradation of 55%-was isolated and identified as Aspergillus versicolor (ARF5). The culture medium was also optimized with different physical and chemical parameters for maximum PU degradation. The presence of CO2 as a by-product of PU biodegradation was confirmed through the Sturm test.

Biodegradation of polyurethanes by Staphylococcus warneri and by microbial co-culture

With the increasing production and use of polyurethanes (PUs), it is necessary to develop sustainable techniques for the remediation of plastic pollution. The use of microorganisms capable of biodegrading PUs may be an environmentally desirable solution for controlling these plastic contaminants. To contribute to the discovery of alternatives for the mitigation of plastics in the environment, this study aimed to explore the potential of StaphylococcuswarneriUFV_01.21, isolated from the gut of Galleria mellonellalarvae, for biodegradation of PU in pure culture and microbial co-culture with Serratia liquefaciensL135. S. warneri grew using Impranil® PU as the sole carbon source in pure culture and co-culture. With six days of incubation, the biodegradation of Impranil® in Luria Bertani broth was 96, 88 and 76%, while in minimal medium, it was 58, 54 and 42% for S. warneri, S. liquefaciens, and co-culture, respectively. In addition, S. warneri in pure culture or co-culture was able to biodegrade, adhere and form biofilms on the surfaces of Impranil® disks and poly[4,4′-methylenebis (phenyl isocyanate)-alt-1,4-butanediol/di(propylene glycol)/polycaprolactone] (PCLMDI) films. Scanning electron microscopy also revealed biodegradation by detecting the formation of cracks, furrows, pores, and roughness on the surfaces of inoculated PU, both with pure culture and microbial co-culture. This study is the first to demonstrate the potential of S. warneriin PU biodegradation.

Study on biodegradation of polyurethane coating on PCB by Aspergillus brasiliensis in space

Polyurethane (PU) is a commonly used conformal coating for printed circuit boards (PCBs). Filamentous fungi present in the space station environment are capable of degrading PU coatings, thereby posing a threat to the safety of electronic components. Therefore, we conducted a 90-day interaction test between Aspergillus brasiliensis and PU-coated PCBs in the China Space Station (CSS) and a controlled environment on the ground. This research aimed to investigate the alterations in the physiological properties of A. brasiliensis on PCB surfaces and the deterioration behavior of PU coating systems in the space microgravity environment. The results show that many fungal parameters, such as growth, morphology, cell ultrastructure, and low molecular weight organic acids (LMWOA) accumulation showed strong changes after spaceflight compared to ground controls. Distinct corrosion morphological features were found in the internal coatings by FIB/SEM analysis, suggesting the existence of a particular deterioration mechanism in the microgravity environment, which requires further investigation.

Fungal Biodegradation of Polyurethanes.

Polyurethanes (PURs) are versatile polymers used in a wide variety of fields, such as the medical, automotive, textile, thermal insulation, and coating industries as well as many everyday objects. Many PURs have applications that require a long service life, sometimes with exposure to aggressive conditions. They can undergo different types of physicochemical and biological degradation, but they are not compostable, and many of them constitute persistent waste in the environment. Although both bacteria and fungi can be involved in the degradation of PURs, fungi are often the main biodegradation agents. The chemical structure of PURs determines their degree of biodegradation. Fungal biodegradation of PURs is linked to the production of enzymes, mainly esterases and proteases, alongside laccases, peroxidases, and tyrosinases, which can modify the structure of polyurethane compounds by forming carbonyl groups. The experimental analysis of the biodegradation of PUR can be carried out by bringing the polymer into contact with a mold in pure culture or with a microbial consortium. Then, global measurements can be taken, such as weight loss, tensile tests, or the ability of microorganisms to grow in the presence of PUR as the sole carbon source. The analysis of the chemical structure of the polymer and its degradation products after fungal growth can confirm biodegradation and specify the mechanism. The main avenues of future research are directed towards the development of fully biodegradable PURs and, on the contrary, towards the development of PURs that are more resistant to degradation phenomena, in particular biodegradation, for applications where the material is in contact with living organisms.

Biodegradation of polyurethanes by Serratia liquefaciens L135 and its polyurethanase: In silico and in vitro analyses

Polyurethanes (PUs) are found in many everyday products and their disposal leads to environmental accumulation. Therefore, there is an urgent need to develop ecologically sustainable techniques to biodegrade and recycle this recalcitrant polymer and replace traditional methods that form harmful by-products. Serratia liquefaciens L135 secretes a polyurethanase with lipase activity, and this study explores the biodegradation of PUs by this bacterium and its enzyme through in silico and in vitro analyses. PUs monomers and tetramers were constructed in silico and tested with modeled and validated structure of the polyurethanase from S. liquefaciens. The molecular docking showed that all PUs monomers presented favorable interactions with polyurethanase (values of binding energy between −84.75 and −121.71 kcal mol−1), including PU poly[4,4′-methylenebis (phenyl isocyanate)-alt-1,4-butanediol/di (propylene glycol)/polycaprolactone] (PCLMDI). Due to repulsive steric interactions, tetramers showed less favorable interactions (values between 24.26 and −45.50 kcal mol−1). In vitro analyses evaluated the biodegradation of PUs: Impranil® and PCLMDI; this latter showed high binding energy with this polyurethanase in silico. The biodegradation of Impranil® by S. liquefaciens and its partially purified polyurethanase was confirmed in agar by forming a transparent halo. Impranil® disks inoculated with S. liquefaciens and incubated at 30 °C for six days showed rupture of the PU structure, possibly due to the formation of cracks visualized by scanning electron microscopy (SEM). PCLMDI films were also biodegraded by S. liquefaciens after 60 days of incubation, with the formation of pores and cracks visualized by SEM. The biodegradation may have occurred due to the action of polyurethanase produced by this bacterium. This work provides essential information on the potential of S. liquefaciens to biodegrade PUs through in silico analyses combined with in vitro analyses.

Plastisphere and microorganisms involved in polyurethane biodegradation

Rapid accumulation of end-of-life polyurethanes (PUR) in the environment is a global crisis. While biodegradation of PUR has been reported, the process is slow, and the microbiology involved in PUR biodegradation is poorly understood. This study reported the microbial community involved in PUR biodegradation (designed as PUR-plastisphere) in estuary sediments, and isolation and characterization of two PUR-utilizing isolates. PUR foams were pretreated with oxygen plasma (referred as p-PUR foams) to mimic weathered conditions before embedded in microcosms containing estuary sediments. After 6 months of incubation, a substantial loss of ester/urethane bonds on the embedded p-PUR foams was observed, according to Fourier transform infrared (FTIR) spectroscopy. Analysis of PUR-plastisphere showed two dominant genera, Pseudomonas (2.7 %) and Hyphomicrobium (3.0 %), along with many unknown genera in Sphingomonadaceae (9.2 %), and predicted hydrolytic enzymes such as esterases and proteases. Purpureocillium sp., and Pseudomonas strain PHC1 (designated as strain PHC1 hereafter), isolated from the PUR plastisphere, can grow on Impranil (a commercial water-borne PUR) as a sole nitrogen or carbon source. High esterase activities were detected in the spent Impranil-containing media, and a significant loss of ester bonds of the spent Impranil was also observed. After 42 days of incubation, the strain PHC1-inoculated p-PUR foam showed a noticeable development of biofilm as observed via scanning electron microscopy (SEM), and disappearance of ester and urethane bonds of the PUR as detected by FTIR, supporting the role of strain PHC1 in biodegradation of the p-PUR foam. Also, the FTIR spectra observed for the sediment-embedded p-PUR foams was similar to those for the strain PHC1-inoculated p-PUR foams, suggesting the potential role of the dominant species of Pseudomonas in PUR-plastisphere. The results of this study showed the promise of rapid biodegradation of PUR foam through inoculating with a PUR-utilizing isolate, Pseudomonas strain PHC1.

Preliminary identification of soil fungi for the degradation of polyurethane film.

Polyurethane (PU) is a versatile plastic that boasts high environmental resistance. The biodegradation of PU has become a hot topic of research aimed at finding ways to potentially solve PU pollutants. Identifying microorganisms capable of efficiently degrading PU plastics is pivotal for the development of a green recycling process for PU. This study aimed to isolate and characterize PU-degrading fungi from the soil of a waste transfer station in Luoyang, China. We isolated four different fungal strains from the soil. Among the isolates, the P2072 and P2073 strains were identified as Rhizopus oryzae (internal transcribed spacer identity, 99.66%) and Alternaria alternata (internal transcribed spacer identity, 99.81%), respectively, through microscopic, morphologic, as well as 18S rRNA sequencing. The degradation ability of strains P2072 and P2073 was analyzed through measurement of weight loss, and they exhibited a degradation rate of 2.7% and 3.3%, respectively, for the PU films after 2months' growth in mineral salt medium (MSM) with PU films as the sole carbon source. In addition, the P2073 strain exhibited protease activity in the presence of PU. To our knowledge, R. oryzae has never been reported as a PU-degrading fungus. This study provides a new perspective on the biodegradation of PU.

Biodegradation of polyurethane by the microbial consortia enriched from landfill.

Polyurethanes (PU) are one of the most used categories of plastics and have become a significant source of environmental pollutants. Degrading the refractory PU wastes using environmentally friendly strategies is in high demand. In this study, three microbial consortia from the landfill leachate were enriched using PU powder as the sole carbon source. The consortia efficiently degraded polyester PU film and accumulated high biomass within 1week. Scanning electron microscopy, Fourier transform infrared spectroscopy, and contact angle analyses showed significant physical and chemical changes to the PU film after incubating with the consortia for 48h. In addition, the degradation products adipic acid and butanediol were detected by high-performance liquid chromatography in the supernatant of the consortia. Microbial composition and extracellular enzyme analyses revealed that the consortia can secrete esterase and urease, which were potentially involved in the degradation of PU. The dominant microbes in the consortia changed when continuously passaged for 50 generations of growth on the PU films. This work demonstrates the potential use of microbial consortia in the biodegradation of PU wastes. KEY POINTS: • Microbial consortia enriched from landfill leachate degraded polyurethane film. • Consortia reached high biomass within 1week using polyurethane film as the sole carbon source. • The consortia secreted potential polyurethane-degrading enzymes.

Polyurethane biodegradation by Serratia sp. HY-72 isolated from the intestine of the Asian mantis Hierodula patellifera.

Polyurethane (PU), currently replacing existing synthetic materials worldwide, is a synthetic polymer derived from polyols, isocyanates, and a chain extender added by condensation reactions. PU wastes which are difficult to recycle, are commonly discarded in landfills and flow into ecosystems, thereby causing serious environmental problems. In recent years, insect-associated microbes have become a promising, eco-friendly strategy as an alternative to plastic recycling. This study aimed to evaluate the potential of Serratia sp. HY-72 strain isolated from the intestine of the Asian mantis (Hierodula patellifera) for PU degradation. The 65 kDa family I.3 lipase which degrades PU was identified and characterized, with a specific activity of 2,883 U mg-1. The bacterial filtrates and the recombinant lipase degraded Impranil (a colloidal polyester-PU dispersion, 100 g l-1) by 85.24 and 78.35% after 72 h incubation, respectively. Fourier transform infrared spectroscopy analysis revealed changes in Impranil functional groups, with decreased C=O functional group and aliphatic chain signals, and increased N-H bending with C-N stretching and C-O stretching. The current study also revealed that the HY-72 strain biodegraded the commercial PU foams (polyester- and polyether- PU) with 23.95 and 10.95% weight loss after 2 weeks, respectively with changes in surface morphology and structure such as cracks, roughness, and surface roughening. Altogether, this is one of the few studies reporting biodegradation of PU by the insect-associated microbe. These findings suggest that the insect-associated microbe could be a promising resource for biodegradation and recycling of plastic waste.

Biodegradation of polyurethane by Japanese carpenter bee gut-associated symbionts Xanthomonas sp. HY-71, and its potential application on bioconversion

In this study, we evaluated the effects of the Xanthomonas sp. HY-71 strain isolated from the intestine of a Japanese carpenter bee ( Xylocopa appendiculata ), on polyurethane (PU) degradation and bioconversion. The abilities of the strain to degrade polyacrylic-, polyester-, and polyether-based PU were characterized by weight loss measurement, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM), and chemical composition analysis. The cell-free filtrates of the strain showed 88.12% of acryl PU-Siegel degradation rates (100 mg/mL) within 3 days. FTIR spectroscopy revealed changes in functional groups, with decreased C=O (1725 cm −1 ) and aliphatic chain signals (704 cm −1 ) and increased N–H stretching (3314 cm −1 ), N–H bending with C–N stretching (1524 cm −1 ), C–O–C stretching (1040 cm −1 ), and C–N stretching (1226 cm −1 ). Polyester-PU and polyether-PU foams, respectively, lost 23.95% and 10.95% of their weight after 2 weeks. SEM revealed surface morphology and structural changes such as holes, cracks, roughness, and grooves. In addition, the bioconversion capability of HY-71 using PU as a nutritional source was also demonstrated by monitoring the exopolysaccharide production yield in the presence of PU foam. The exopolysaccharide yields with acryl PU-Siegel and PS-PU foam (24.6 g/L and 22.6 g/L, respectively) were significantly higher than those of the control and polyether-PU treatments. This study is the first on the insect gut microbe Xanthomonas sp. HY-71 strain, which has PU degradation capability, and provides insight into the potential applications of insect-related bacteria in plastic waste management. • Insect symbiotic bacteria have potential application in plastic biodegradation. • Xanthomonas strain from Japanese carpenter bee is effective PU-degradable bacterium. • Xanthomonas strain was able to use polyacryl-based PU as a nutritional source. • Xanthomonas strain was able to degrade other types of PS-PU and PE-PU.

Concerted action of extracellular and cytoplasmic esterase and urethane-cleaving activities during Impranil biodegradation by Alicycliphilus denitrificans BQ1.

The concerted action of commercial esterases, proteases and amidases has been demonstrated to be relevant in polyurethane (PU) degradation by in vitro experiments. However, the spatial and temporal dynamics of these activities during PU biodegradation by PU-degrading bacteria have not been addressed. Here, we examined the capability of Alicycliphilus denitrificans BQ1 to biodegrade the polyester (PS)-PU Impranil, analyzed the temporal and spatial coordination between the extracellular and cytoplasmic esterase and urethane-cleaving activities, and their independent and combined effects on Impranil biodegradation. A. denitrificans BQ1 grew in Impranil, and its clearing was correlated with the cleavage of ester and urethane groups since early times, with decrements of some Impranil compounds and the appearance of biodegradation products. While extracellular esterase was active at early times with its maximum at 18h, urethanase appeared at this time and increased up to the end of the analysis (48h), with the cytoplasmic activities behaving similarly but with lower levels than the extracellular ones. Both enzymatic activities exhibited distinct substrate specificity depending on their cellular localization and cultivation times, suggesting they cleave differentially located groups. As the urethane cleavage occurred since early times, when no urethane-cleaving activity was detected, different proteins should be acting at early and late times. In vitro experiments with independent or combined cellular protein fractions supported the previous deduction and confirmed the concerted action of extracellular and cytoplasmic esterase and urethane-cleaving activities. A two-stage process for Impranil degradation by A. denitrificans BQ1 is proposed.

Current advances in polyurethane biodegradation

AbstractWhile plastics bring convenience to industrial production and daily life, serious environmental problems are always accompanied. Polyurethane is an important polymeric material with versatile applications, but it also accounts for severe plastic contamination worldwide. Since it is difficult for polyurethanes to be completely degraded under natural conditions, the discovery of polyurethane‐degrading microorganisms and correlative ‘polyurethanase’ enzymes brings hope to polyurethane biodegradation. Polyurethane materials can be divided into two major types: polyester‐polyurethane and polyether‐polyurethane. In this review, we summarize the biodegradation mechanisms of these two types of polyurethane and recent research progress on the biodegradation of polyurethane via both microorganisms and enzymes. Furthermore, solutions that could be taken into consideration for the biodegradation of polyurethane in the future are also discussed. © 2021 Society of Industrial Chemistry.

Isolation and characterization of a polyurethane-degrading bacterium

Biodegradation of polyurethane (PUR) pollutants by microorganisms has received widespread attention currently. Identification of microorganisms capable of efficiently degrading PUR plastics is a key point. In this study, a strain P10 capable of degrading PUR was isolated from the plastic wastes, and identified as a bacterium belonging to the genus of Brevibacillus based on colony morphology and 16S rDNA phylogenetic analysis. Brevibacillus sp. P10 was capable of degrading 71.4% of waterborne polyurethane (Impranil DLN) after 6 days growth in MSM medium with DLN as a sole carbon source. In addition, strain P10 can use commercial PUR foam as the sole carbon source for growth. Brevibacillus sp. P10 can degrade 50 mg PUR foam after 6 days growth in MSM medium supplemented with 5% (V/V) LB after optimization of degradation conditions. This indicates that Brevibacillus sp. P10 has potential to be used in biodegradation of PUR waste.

Effect of different bacteria on the biodegradation of polyurethane

Polyurethane has been used and over-exploited worldwide in the manufacture of different goods, but it is hard to break down and represents an important contaminant due to its accumulation when discarded. Recent research findings have shown that several bacteria and their enzymes can biodegrade various plastics, such as polyurethane. In this review, we sought to group, analyze, and relate the techniques used by different bacterial species to biodegrade polyurethane that have been identified in different studies by searching databases, such as PubMed, Web of Science, and Scopus. Different species of proteobacteria, actinobacteria, and endobacteria biodegrade polyurethane by oxidation and hydrolysis to obtain carbon and nitrogen sources. Changes as weight loss, tensile strength, and chemical and surface changes were observed in polymer properties, showing that biological technologies have a direct impact on polyurethane by modifying the molecule in different ways.

Toward Biorecycling: Isolation of a Soil Bacterium That Grows on a Polyurethane Oligomer and Monomer.

The fate of plastic waste and a sustainable use of synthetic polymers is one of the major challenges of the twenty first century. Waste valorization strategies can contribute to the solution of this problem. Besides chemical recycling, biological degradation could be a promising tool. Among the high diversity of synthetic polymers, polyurethanes are widely used as foams and insulation materials. In order to examine bacterial biodegradability of polyurethanes, a soil bacterium was isolated from a site rich in brittle plastic waste. The strain, identified as Pseudomonas sp. by 16S rRNA gene sequencing and membrane fatty acid profile, was able to grow on a PU-diol solution, a polyurethane oligomer, as the sole source of carbon and energy. In addition, the strain was able to use 2,4-diaminotoluene, a common precursor and putative degradation intermediate of polyurethanes, respectively, as sole source of energy, carbon, and nitrogen. Whole genome sequencing of the strain revealed the presence of numerus catabolic genes for aromatic compounds. Growth on potential intermediates of 2,4-diaminotoluene degradation, other aromatic growth substrates and a comparison with a protein data base of oxygenases present in the genome, led to the proposal of a degradation pathway.

A new insight of degradation and stability performance of polyurethane and its composites

Polyurethane and its composites have been synthesized using 4,4’-methylene bis(cyclohexyl) isocyanate and the catalyst dibutyltin dilaurate. The chemical ageing such as hydrolytic stability (ethanol, water, and salt solution), chemical stability (acid, base and oxidizing agent) and stability in organic solvents (ethyl methyl ketone, acetone, toluene, chloroform, dimethyl acetamide) have been undertaken and the results are discussed. Thermal stability is also done and the results are discussed. The bio-degradability of polyurethanes and its composites have also been tested by soil burial test and assessed by scanning electron microscopic (SEM) analysis.

Biodegradative Activities of Selected Environmental Fungi on a Polyester Polyurethane Varnish and Polyether Polyurethane Foams.

Polyurethane (PU) is widely used in many aspects of modern life because of its versatility and resistance. However, PU waste disposal generates large problems, since it is slowly degraded, there are limited recycling processes, and its destruction may generate toxic compounds. In this work, we isolated fungal strains able to grow in mineral medium with a polyester PU (PS-PU; Impranil DLN) or a polyether PU (PE-PU; Poly Lack) varnish as the only carbon source. Of the eight best Impranil-degrading strains, the six best degraders belonged to the Cladosporium cladosporioides complex, including the species C. pseudocladosporioides, C. tenuissimum, C. asperulatum, and C. montecillanum, and the two others were identified as Aspergillus fumigatus and Penicillium chrysogenum The best Impranil degrader, C. pseudocladosporioides strain T1.PL.1, degraded up to 87% after 14 days of incubation. Fourier transform infrared (FTIR) spectroscopy analysis of Impranil degradation by this strain showed a loss of carbonyl groups (1,729 cm(-1)) and N-H bonds (1,540 and 1,261 cm(-1)), and gas chromatography-mass spectrometry (GC-MS) analysis showed a decrease in ester compounds and increase in alcohols and hexane diisocyanate, indicating the hydrolysis of ester and urethane bonds. Extracellular esterase and low urease, but not protease activities were detected at 7 and 14 days of culture in Impranil. The best eight Impranil-degrading fungi were also able to degrade solid foams of the highly recalcitrant PE-PU type to different extents, with the highest levels generating up to 65% of dry-weight losses not previously reported. Scanning electron microscopy (SEM) analysis of fungus-treated foams showed melted and thinner cell wall structures than the non-fungus-treated ones, demonstrating fungal biodegradative action on PE-PU. Polyurethane waste disposal has become a serious problem. In this work, fungal strains able to efficiently degrade different types of polyurethanes are reported, and their biodegradative activity was studied by different experimental approaches. Varnish biodegradation analyses showed that fungi were able to break down the polymer in some of their precursors, offering the possibility that they may be recovered and used for new polyurethane synthesis. Also, the levels of degradation of solid polyether polyurethane foams reported in this work have never been observed previously. Isolation of efficient polyurethane-degrading microorganisms and delving into the mechanisms they used to degrade the polymer provide the basis for the development of biotechnological processes for polyurethane biodegradation and recycling.

Polyurethanes made from bile acids

New polyurethanes based on bile acids were synthesized from alcohol derivatives of cholic and lithocholic acids and hexamethylene diisocyanate, in an effort to improve the biocompatibility and biodegradability of polyurethanes through the use of natural compounds. The hydrogen bonding in the polymers is confirmed by IR spectral analysis. The glass transition temperatures of the polymers are in the range of 82-138 °C and degradation temperatures in the range of 267-298 °C as studied by thermal analyses. Thermogravimetric studies indicate that the comonomers are of equimolar amounts in the polyurethanes derived from both bile acids.

Preliminary study on the biodegradation of adipate/phthalate polyester polyurethanes of commercial‐type by Alicycliphilus sp. BQ8

ABSTRACTAccumulation of polyurethane (PU) waste has increased considerably due to its extensive use. Even though many efforts are being carried out to develop more biodegradable PU, the use of these new materials is far from being commercially available. Here, we analyzed the susceptibility of solid polyester polyurethanes (PS‐PU) of commercial‐type, to biodegradation by Alicycliphilus sp. BQ8, a polyurethanolytic bacterial strain. Four polyester polyols were synthesized from dipropylene glycol (DPG) or diethylene glycol (DEG), and adipic acid (ADA) or phthalic anhydride (PHA), and were combined with either 4,4′‐ and 4,2′‐methylene diphenyldiisocyanate (MDI) or 2,4‐ and 2,6‐toluene diisocyanate (TDI). Synthesized polyols and PUs were characterized. PU biodegradation was assessed by the capacity of the polymers to support bacterial growth, and by scanning electron microscopy (SEM), Fourier transformed infrared (FTIR) spectroscopy, and gas chromatography/mass spectrometry (GC‐MS) analyses. Although all the synthesized PUs supported BQ8 growth, SEM analysis showed that PHA‐based PU foams were the most affected by bacterial growth. FTIR spectroscopy and GC‐MS analyses of bacterial treated PS‐PUs showed that they were attacked at ester and urethane groups, suggesting that esterase and amidase activities are involved. Extra‐cellular and membrane bound esterase activities were detected during the five days of analysis. Our results suggest that solid PHA‐based PUs might be more susceptible than ADA‐based PUs to microbial biodegradation in the environment. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42992.