Chloroform induces outstanding crystallization of poly(hydroxybutyrate) (PHB) vesicles within bacteria.
Poly[(R)-3-hydroxyalkanoate]s or PHAs are aliphatic polyesters produced by numerous microorganisms. They are accumulated as energy and carbon reserve in the form of small intracellular vesicles. Poly[(R)-3-hydroxybutyrate] (PHB) is the most ubiquitous and simplest PHA. An atomic force microscope coupled with a tunable infrared laser (AFM-IR) was used to record highly spatially resolved infrared spectra of commercial purified PHB and native PHB within bacteria. For the first time, the crystallinity degree of native PHB within vesicle has been directly evaluated in situ without alteration due to the measure or extraction and purification steps of the polymer: native PHB is in crystalline state at 15% whereas crystallinity degree reaches 57% in commercial PHB. Chloroform addition on native PHB induces crystallization of the polymer within bacteria up to 60%. This possibility of probing and changing the physical state of polymer in situ could open alternative ways of production for PHB and others biopolymers. Graphical abstract An atomic force microscope coupled with a tunable infrared laser (AFM-IR) has been used to record local infrared spectra of biopolymer PHB within bacteria. Deconvolution of those spectra has allowed to determine in situ the crystallinity degree of native PHB.
Laboratoire de Chimie Physique, CNRS UMR 8000, Université Paris-Sud, 91405, Orsay, France.
Rolando
R
Rebois
Laboratoire de Chimie Physique, CNRS UMR 8000, Université Paris-Sud, 91405, Orsay, France. delphine.onidas@u-psud.fr.|Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, 45 rue des saints-pères, 75006, Paris, France. delphine.onidas@u-psud.fr.
Delphine
D
Onidas
Light Light Solutions, Athens, GA, 30608, USA.|Department of Materials Science and Engineering, University of Delaware, Newark, DE, 19716, USA.
Curtis
C
Marcott
Department of Materials Science and Engineering, University of Delaware, Newark, DE, 19716, USA.|Danimer Scientific, Bainbridge, GA, 39817, USA.
Isao
I
Noda
Laboratoire de Chimie Physique, CNRS UMR 8000, Université Paris-Sud, 91405, Orsay, France.
Alexandre
A
Dazzi
D002152:Calorimetry, Differential Scanning; D002725:Chloroform / Q000494:pharmacology*; D003460:Crystallization; D006885:Hydroxybutyrates / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D011108:Polymers / Q000737:chemistry*; D011208:Powders; D012242:Rhodobacter sphaeroides / Q000187:drug effects* / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared
D006885:Hydroxybutyrates; D011108:Polymers; D011208:Powders; D002725:Chloroform
AFM-IR; Bacterial poly(hydroxybutyrate); Chemical map; Degree of crystallinity; Nanoscale infrared spectroscopy