Title: A novel alkaline esterase from Sporosarcina sp. nov. strain eSP04 catalyzing the hydrolysis of a wide variety of aryl-carboxylic acid esters Takehara M, Kinoshita K, Miyamoto M, Hirohara H Ref: Biosci Biotechnol Biochem, 76:1721, 2012 : PubMed
A novel esterase showing activity specific for esters of aryl-carboxylic acids was discovered in Sporosarcina sp. nov., which was identified by the 16S rDNA sequencing method in addition to morphological and physiological analyses. The aryl-carboxylesterase (named EstAC) was purified 780-fold from crude cell extracts by a 5-step procedure. EstAC was characterized as a monomeric protein with a molecular weight of 43,000, an optimum pH of around 9.0, and an optimum temperature of 40 degrees C. The pH optimum and the effects of inhibitors together with an internal amino acid sequence suggested that EstAC is a member of family VIII esterases. EstAC was found to be highly active on a wide variety of substrates such as alkyl benzoates, alkyl phenylacetates, ethyl alpha- or beta-substituted phenylpropionates, dialkyl terephthalates, dimethyl isophthalate, and ethylene glycol dibenzoate. However, monomethyl terephthalate was not hydrolyzed. It was suggested that EstAC had 4-hydroxybenzoyl and cinnamoyl esterase activities as well.
Title: Enzymes for the biofunctionalization of poly(ethylene terephthalate) Zimmermann W, Billig S Ref: Adv Biochem Eng Biotechnol, 125:97, 2011 : PubMed
The functionalization of synthetic polymers such as poly(ethylene terephthalate) to improve their hydrophilicity can be achieved biocatalytically using hydrolytic enzymes. A number of cutinases, lipases, and esterases active on polyethylene terephthalate have been identified and characterized. Enzymes from Fusarium solani, Thermomyces insolens, T. lanuginosus, Aspergillus oryzae, Pseudomonas mendocina, and Thermobifida fusca have been studied in detail. Thermostable biocatalysts hydrolyzing poly(ethylene terephthalate) are promising candidates for the further optimization of suitable biofunctionalization processes for textile finishing, technical, and biomedical applications.
We isolated a fungal strain HS-1 utilizing either ethylene glycol dibenzoate or ethyl benzoate as sole source of carbon and energy, and identified it as Aspergillus nomius, based on morphological and rDNA analyses. An enzyme hydrolyzing the esters was purified from the culture supernatant of the strain to an electrophoretically homogeneous state. The enzyme was a carboxyl esterase with a monomeric structure, of which the molecular mass was about 60000, and inhibited by phenylmethylsulfonyl fluoride. The enzyme hydrolyzed various benzoate esters and p-nitrophenyl esters, and its hydrolysis rates for the most favorable substrates, n-butyl benzoate and p-nitrophenyl valerate, were comparable.
