Characterization of photosynthetically synthesized poly(3-hydroxybutyrate) using a randomly mutated strain of Synechocystis sp. PCC 6714

Abstract

Conventional polymers are made from fossil resources and consume fossil energy in their production, yielding CO 2 emissions. Production of large-volume compounds from CO 2 , either from point sources or from the air, could reduce anthropogenic global warming. Poly(3-hydroxybutyrate) (PHB) is a biodegradable and biobased thermoplastic polymer which can be synthesized sustainably using CO 2. PHB exhibits a high crystallinity and shows properties similar to synthetic polyesters and also to polyolefins such as polypropylene. However, the low elongation at break and the brittleness of PHB are limitations, which, however, can be overcome by using other polyhydroxyalkanoates (PHA) as blends or copolymers. In this study, PHB produced by cyanobacteria from CO 2 was extracted and characterized using various techniques. The Fourier Transform Infrared spectroscopy (FTIR) showed the characteristic signals expected for the phototrophic PHB. Differential Scanning Calorimetry (DSC) for thermal characterization of PHB showed a melting temperature of 151.42°C and 73.11°C for the crystallization process. From the Gel Permeation Chromatography (GPC) the molecular weight of cyanobacterial PHB was determined to be 1,051,900 g mol −1. The analytics results show that the photosynthetically produced PHB ressembles conventional PHB from sugar fermentation, which is an established biopolymer today. It can be concluded that photosynthetically produced PHB has a strong market potential, backed by its sustainable production technology.

Characterization and Biotechnological Potential of Intracellular Polyhydroxybutyrate by Stigeoclonium sp. B23 Using Cassava Peel as Carbon Source

“…In addition, a glass transition temperature similar to the present study was found in a strain of Synechocystis sp. [ 34 ]. Nevertheless, the glass transition temperature of PHB extracted from Lysinibacillus sphaericus was 140 °C, proving that high glass transition temperatures of different types of PHB can be determined in different microorganisms [ 66 ].…”

“…The physicochemical and morphological characterization of PHB provide a clear understanding of the polymeric properties when compared to polymers of petrochemical origin and they have not been already well-developed in bacteria biopolymers [ 10 ]. Marine cyanobacteria and microalgae have become more sensitive to this low manipulation and offer further research that confirms the large and useful properties of these polymers for later use in medical applications such as drug carrier biomaterials, tissue engineering scaffolds, and others [ 21 , 24 , 34 , 35 , 36 ]. The aim of this article was therefore to study the chemical, physical, morphological, and biological characterization of a novel biotechnological polyhydroxybutyrate by microalgae Stigeoclonium sp.…”

Maximizing PHB content in Synechocystis sp. PCC 6803: a new metabolic engineering strategy based on the regulator PirC

“…In previous analyses the average molecular weight of PHB from Synechocystis and Synechocystis sp. PCC 6714 was determined at Mn ~ 130 and 316 kg mol −1 , respectively [ 27 , 37 ]. Compared to these, the PHB derived from PPT1 with an average weight of 503 kg/mol is high-molecular.…”

Biopolymer composites: a review

“…The mechanical properties of PHBs are similar to the properties of petroleum-based plastics such as polyethylene (PE) and polypropylene (PP) [67]. The PHAs do not need any arable land for the production and can be even produced from CO 2 in a marine environment [75,76].…”