Biodegradation of bis(2‐hydroxyethyl) terephthalate by a newly isolated Enterobacter sp. HY1 and characterization of its esterase properties

Abstract

Bis(2‐hydroxyethyl) terephthalate (BHET) is an important compound produced from poly(ethylene terephthalate) (PET) cleavage. It was selected as the representative substance for the study of PET degradation. A bacterial strain HY1 that could degrade BHET was isolated and identified as Enterobacter sp. The optimal temperature and pH for BHET biodegradation were determined to be 30°C and 8.0, respectively. The half‐life of degradation was 70.20 h at an initial BHET concentration of 1,000 mg/L. The results of metabolites' analysis by liquid chromatograph–mass spectrometer revealed that BHET was first converted to mono‐(2‐hydroxyethyl) terephthalate (MHET) and then to terephthalic acid. Furthermore, an esterase‐encoding gene, estB, was cloned from strain HY1, and the expressed enzyme EstB was characterized. The esterase has a molecular mass of approximately 25.13 kDa, with an isoelectric point of 4.68. Its optimal pH and temperature were pH 8.0 and 40°C, respectively. The analysis of the enzymatic products showed that EstB could hydrolyze one ester bond of BHET to MHET. To the best of authors' knowledge, this is the first report on the biodegradation characteristics of BHET by a member of the Enterobacter genus.

Environmental Consortium Containing Pseudomonas and Bacillus Species Synergistically Degrades Polyethylene Terephthalate Plastic

“…The presence of the cytoplasmic Pseudomonas YpfH, lacking a secretion signal, which is functionally similar to the recently described Enterobacter sp. HY1 EstB able to cleave BHET (35), may explain why strains 9.2, 10, and 13.2 grew on BHET (Fig. 3), while secreted enzymes from these strains did not significantly degrade this compound (Fig.…”

Chemo‐Biological Upcycling of Poly(ethylene terephthalate) to Multifunctional Coating Materials

“…The enzyme reaction was carried out in 50 m m Tris‐HCl buffer (pH 7.5) at 30 °C in the presence of 2 U mL −1 of Bs2Est according to the previous study. [21] The enzyme hydrolysis was stopped by adding methanol (Figure S6b) in the ratio of 1 : 19 ( v / v ), and the reaction mixture was filtered by 0.22 μm nylon membrane (Choice filter, Thermo Scientific) to analyze substrate and products using HPLC system. Purified TPA was simply obtained by subsequent acidification and filtration according to the previous study.…”

Perspectives on the Role of Enzymatic Biocatalysis for the Degradation of Plastic PET

“…Es EstB, or EstB, is an esterase from Enterobacter sp. HYI isolated and characterized by Qiu et al [ 236 ] in 2020. The enzyme was shown to be able to degrade BHET to MHET and TPA.…”