Hydrolysis of cyclic poly(ethylene terephthalate) trimers by a carboxylesterase from Thermobifida fusca KW3

Abstract

We have identified a carboxylesterase produced in liquid cultures of the thermophilic actinomycete Thermobifida fusca KW3 that were supplemented with poly(ethylene terephthalate) fibers. The enzyme hydrolyzed highly hydrophobic, synthetic cyclic poly(ethylene terephthalate) trimers with an optimal activity at 60 degrees C and a pH of 6. V (max) and K (m) values for the hydrolysis were 9.3 micromol(-1) min(-1) mg(-1) and 0.5 mM, respectively. The esterase showed high specificity towards short and middle chain-length fatty acyl esters of p-nitrophenol. The enzyme retained 37% of its activity after 96 h of incubation at 50 degrees C and a pH of 8. Enzyme inhibition studies and analysis of substitution mutants of the carboxylesterase revealed the typical catalytic mechanism of a serine hydrolase with a catalytic triad composed of serine, glutamic acid, and histidine.

A dual enzyme system composed of a polyester hydrolase and a carboxylesterase enhances the biocatalytic degradation of polyethylene terephthalate films

“…1A. The incubation of free TfCa above 55°C resulted in a complete loss of activity confirming results of a previous study [23]. In contrast, the immobilized enzyme maintained approximately 94% of its initial activity at 60°C.…”

“…The carboxylesterase TfCa from Thermobida fusca KW3 was employed as the second biocatalyst in the dual enzyme reaction system to hydrolyze the soluble PET degradation products MHET and BHET generated by the polyester hydrolases. TfCa preferentially hydrolyzes short chain esters such as p ‐nitrophenyl acetate and p ‐NPB was well as cyclic PET trimers . While the optimum temperature for the hydrolysis of cyclic PET trimers by TfCa is 60°C, its residual activity of TfCa after an incubation time of 1 h at this temperature was only 10% .…”

Autotransporter domain-dependent enzymatic analysis of a novel extremely thermostable carboxylesterase with high biodegradability towards pyrethroid pesticides

“…The optimum temperature (60 °C) of the recombinant enzyme is similar to that of carboxylesterase from P. aeruginosa PAO1 (55 °C) 6 , Thermobifida fusca KW3 (60 °C) 32 , and Anoxybacillus sp. PDF1 (60 °C) 8 .…”

Enzymatic biofinishes for synthetic textiles

“…The latter phenomenon leads to the soiling of the dye apparatus and to a decrease of heat transmission at the heater elements (Nechwatal et al ., 2006 ). Efforts have been made to catalyse the hydrolysis of PET oligomers and promising results are reported concerning their hydrolysis with lipase and cutinases (Nechwatal et al ., 2006 ;Eberl et al ., 2008 ;Hooker et al ., 2003 ;Billig et al ., 2010 ;Hubbard et al ., 1996 ).…”