Two methods for accurate poly(3-hydroxybutyrate) (PHB) depolymerase activity determination and quantitative and qualitative hydrolysis product determination are described. The first method is based on online determination of NaOH consumption rates necessary to neutralize 3-hydroxybutyric acid (3HB) and/or 3HB oligomers produced during the hydrolysis reaction and requires a pH-stat apparatus equipped with a software-controlled microliter pump for rapid and accurate titration. The method is universally suitable for hydrolysis of any type of polyhydroxyalkanoate or other molecules with hydrolyzable ester bonds, allows the determination of hydrolysis rates of as low as 1 nmol/min, and has a dynamic capacity of at least 6 orders of magnitude. By applying this method, specific hydrolysis rates of native PHB granules isolated from Ralstonia eutropha H16 were determined for the first time. The second method was developed for hydrolysis product identification and is based on the derivatization of 3HB oligomers into bromophenacyl derivates and separation by high-performance liquid chromatography. The method allows the separation and quantification of 3HB and 3HB oligomers up to the octamer. The two methods were applied to investigate the hydrolysis of different types of PHB by selected PHB depolymerases.
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http://dx.doi.org/10.1128/AEM.01184-06 | DOI Listing |
ACS Sustain Chem Eng
May 2024
Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Roger Land Building, Alexander Crum Brown Road, King's Buildings, Edinburgh EH9 3FF, U.K.
The plastic waste crisis is catalyzing change across the plastics life cycle. Central to this is increased production and application of bioplastics and biodegradable plastics. In particular, poly(hydroxybutyrate) (PHB) is a biodegradable bioplastic that can be produced from various renewable and waste feedstocks and is a promising alternative to some petrochemical-derived and non-biodegradable plastics.
View Article and Find Full Text PDFFront Plant Sci
February 2024
Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland.
DSM13060 is an endosymbiont that lives in the cells of shoot tip meristems. The bacterium is methylotrophic and consumes plant-derived methanol for the production of polyhydroxybutyrate (PHB). The PHB provides protection against oxidative stress for both host and endosymbiont cells through its fragments, methyl-esterified 3-hydroxybutyrate (ME-3HB) oligomers.
View Article and Find Full Text PDFNanoscale
September 2023
Department of Physics, University of Ottawa, Ottawa, Ontario, Canada.
Due to their programmability specific base pairing, self-assembled DNA origami structures have proven to be useful for a wide variety of applications, including diagnostics, molecular computation, drug delivery, and therapeutics. Measuring and characterizing these structures is therefore of great interest and an important part of quality control. Here, we show the extent to which DNA nanostructures can be characterized by a solid-state nanopore; a non-destructive, label-free, single-molecule sensor capable of electrically detecting and characterizing charged biomolecules.
View Article and Find Full Text PDFFront Bioeng Biotechnol
February 2022
Department of Materials Science and Engineering, Tokyo Institute of Technology, Yokohama, Japan.
Poly(3-hydroxybutyrate) [P(3HB)] is the most representative polyhydroxyalkanoate (PHA), which is a storage polyester for prokaryotic cells. P(3HB)-producing recombinant secretes diethylene glycol (DEG)-terminated 3HB oligomers (3HBO-DEG) through a PHA synthase-mediated chain transfer and alcoholysis reactions with externally added DEG. The purpose of this study was to optimize the culture conditions for the secretory production of 3HBO-DEG with jar fermenters.
View Article and Find Full Text PDFMicroorganisms
February 2022
Department of Chemistry for Life Sciences and Agriculture, Faculty of Life Sciences, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan.
The biodegradable polyester poly-()-3-hydroxybutyrate [P(3HB)] is synthesized by a polymerizing enzyme called polyhydroxyalkanoate (PHA) synthase and accumulates in a wide variety of bacterial cells. Recently, we demonstrated the secretory production of a ()-3HB oligomer (3HBO), a low-molecular-weight P(3HB), by using recombinant expressing PHA synthases. The 3HBO has potential value as an antibacterial substance and as a building block for various polymers.
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