High-level expression of codon-optimized Thielavia terrestris cutinase suitable for ester biosynthesis and biodegradation

Abstract

A codon-optimized cutinase gene (TtCutopt) from Thielavia terrestris was over-expressed in Pichia pastoris. An extracellular activity reached 10,200 U/mL using high cell density fermentation. The optimal pH and temperature of TtCutopt were 7.0 and 50 °C, respectively. It displayed high stability over a wide range of pH from 3.0 to 11.0 and up to 85 °C. Among tested p-nitrophenyl esters and triglycerides, TtCutopt showed the highest activity towards p-nitrophenyl butyrate and tributyrin, with specificity activity of 2322.4 U/mg and 1152.5 U/mg, respectively. It was extremely stable in organic solvents and surfactants. TtCutopt efficiently catalyzed the synthesis of butyl butyrate, hexyl butyrate, butyl hexanoate and hexyl hexanoate with esterification efficiency of >95%. Furthermore, it catalyzed the degradation of >90% of dimethyl phthalate, diethyl phthalate, dipropyl phthalate and dibutyl phthalate to release their corresponding monoalkyl phthalates within 24 h. Thus, high yield, high stability, and esterification efficiency of TtCutopt make it an attractive candidate for ester biosynthesis and biodegradation.

Keywords: Cutinase; High-level expression; Phthalate ester degradation; Short-chain alkyl ester synthesis; Thielavia terrestris.