Khruengsai Sarunpron, Sripahco Teerapong, Pripdeevech Patcharee
School of Science, Mae Fah Luang University, Chiang Rai, Thailand.
Center of Chemical Innovation for Sustainability (CIS), Mae Fah Luang University, Chiang Rai, Thailand.
Front Microbiol. 2022 Jun 14;13:874842. doi: 10.3389/fmicb.2022.874842. eCollection 2022.
Polyester urethanes (PUR) are widely used in industries and have led to a worldwide plastic waste problem. Thus, novel solutions for PUR degradation are required to reduce environmental pollution. This work investigates the PUR biodegradation efficiency of 33 fungal species using a polyester-polyurethane colloid branded Impranil DLN (Impranil) compared to , which served as the positive control. The biodegradation is evaluated based on its ability to clear Impranil in media. Eleven fungi can clear Impranil in both solid- and liquid-medium assays. The highest degradation was attributed to cultured with Impranil as a carbon source. The degradation was confirmed by the Sturm test, Fourier-transform infrared (FTIR) spectroscopy, and gas chromatography-mass spectrometry (GC-MS). From the Sturm test, CO at a concentration of 0.85 g/L was found in cultured with 150 mL of Impranil solution after a 2-week incubation period while the CO at a concentration of 0.53 g/L was detected from in the same conditions. The biodegradation was further confirmed by evaluating the clearance percentage of supernatant of and culturing with Impranil from the Sturm test. The clearance percentage of and supernatant was 88.84 and 48.97%, respectively. Moreover, the degradation of soft segment and breakdown of ester linkages were observed, as evidenced by the decrease of the carbonyl (1,715 cm) and N-H stretching (1,340 cm and 1,020 cm) FTIR spectral peaks, respectively. GC-MS detected 3Z-heptenol, 5Z-octenol, 2E,4E-hexadienol acetate, and 3E,6Z-nonadienol as degradation products from the culture supernatant. This fungus was screened for its ability to produce extracellular esterase, protease, and urease enzymes. Extracellular esterase, very low urease, and no protease activities were detected in the culture supernatant of in the presence of Impranil. can degrade Impranil partially hydrolysis of ester linkages by cell-bound esterases at a considerable rate without any prior treatment. This fungus not only degraded Impranil but also mineralized them into CO and HO. can be applied in the process of biochemical depolymerization of PUR for the pure monomers recycling.
聚酯型聚氨酯（PUR）在工业中广泛使用，导致了全球性的塑料垃圾问题。因此，需要新的PUR降解解决方案以减少环境污染。本研究使用一种名为英普朗尼DLN（Impranil）的聚酯 - 聚氨酯胶体，与用作阳性对照的[对照物未明确给出]相比，研究了33种真菌对PUR的生物降解效率。基于其在培养基中清除Impranil的能力来评估生物降解情况。11种真菌在固体和液体培养基试验中均能清除Impranil。最高降解率归因于以Impranil作为碳源培养的[真菌名称未明确给出]。通过斯特姆试验、傅里叶变换红外（FTIR）光谱和气相色谱 - 质谱（GC - MS）确认了降解情况。从斯特姆试验可知，在含有150 mL Impranil溶液培养2周后的[真菌名称未明确给出]培养物中发现浓度为0.85 g/L的CO，而在相同条件下从[另一真菌名称未明确给出]中检测到浓度为0.53 g/L的CO。通过评估斯特姆试验中[真菌名称未明确给出]和[另一真菌名称未明确给出]与Impranil共培养上清液的清除率进一步证实了生物降解。[真菌名称未明确给出]和[另一真菌名称未明确给出]上清液的清除率分别为88.84%和48.97%。此外，观察到软段的降解和酯键的断裂，分别由羰基（1715 cm）和N - H伸缩振动（1340 cm和1020 cm）FTIR光谱峰的降低所证明。GC - MS检测到3Z - 庚烯醇、5Z - 辛烯醇、2E,4E - 己二烯醇乙酸酯和3E,6Z - 壬二烯醇作为[真菌名称未明确给出]培养上清液的降解产物。筛选该真菌产生胞外酯酶、蛋白酶和脲酶的能力。在存在Impranil的情况下，在[真菌名称未明确给出]的培养上清液中检测到胞外酯酶、极低的脲酶活性且未检测到蛋白酶活性。[真菌名称未明确给出]可以通过细胞结合的酯酶以相当的速率部分水解酯键来降解Impranil，无需任何预处理。这种真菌不仅降解了Impranil，还将它们矿化为CO₂和H₂O。[真菌名称未明确给出]可应用于PUR的生化解聚过程以实现纯单体的回收利用。
