Related Experiment Video
Updated: May 21, 2026

A High-Yield Streptomyces Transcription-Translation Toolkit for Synthetic Biology and Natural Product Applications
Published on: September 10, 2021
Polyester hydrolytic and synthetic activity catalyzed by the medium-chain-length poly(3-hydroxyalkanoate)
Marta Santos1, Joana Gangoiti, Helmut Keul
1Enzyme and Cell Technology Group, Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080, Bilbao, Spain.
Abstract:
The extracellular medium-chain-length polyhydroxyalkanote (MCL-PHA) depolymerase from an isolate identified as Streptomyces venezuelae SO1 was purified to electrophoretic homogeneity and characterized. The molecular mass and pI of the purified enzyme were approximately 27 kDa and 5.9, respectively. The depolymerase showed its maximum activity in the alkaline pH range and 50 °C and retained more than 70 % of its initial activity after 8 h at 40 °C. The MCL-PHA depolymerase hydrolyzes various p-nitrophenyl-alkanoates and polycaprolactone but not polylactide, poly-3-hydroxybutyrate, and polyethylene succinate. The enzymatic activity was markedly enhanced by the presence of low concentrations of detergents and organic solvents, being inhibited by dithiothreitol and EDTA. The potential of using the enzyme to produce (R)-3-hydroxyoctanoate in aqueous media or to catalyze ester-forming reactions in anhydrous media was investigated. In this sense, the MCL-PHA depolymerase catalyzes the hydrolysis of poly-3-hydroxyoctanoate to monomeric units and the ring-opening polymerization of β-butyrolactone and lactides, while ε-caprolactone and pentadecalactone were hardly polymerized.
Related Concept Videos
Types of Step-Growth Polymers: Polyesters
Polyesters are commonly prepared from terephthalic acid and ethylene glycol; the crude product is known as poly(ethylene terephthalate) or PET. However, polyesters are synthesized industrially by transesterification of dimethyl terephthalate with ethylene glycol at 150 °C. The two reactants and the polymer...
Microbial Bioremediation of Plastics
Bioplastics
Esters to Carboxylic Acids: Acid-Catalyzed Hydrolysis
During hydrolysis, the ester is first activated towards nucleophilic attack through the protonation of the carboxyl oxygen atom by the acid catalyst. The protonation makes the ester carbonyl carbon more electrophilic. In the next step, water acts as a nucleophile and adds to the...
Free-Radical Chain Reaction and Polymerization of Alkenes
Production of Organic Acids

