Biosynthesis and characterization of biodegradable Poly(3-hydroxybutyrate) from renewable sources

Abstract

Poly(3-hydroxybutyrate) was produced in fed-batch cultures of Ralstonia eutropha DSM 428 and Alcaligenes latus ATCC 29712 on a mineral medium with different carbon sources such as sucrose, sodium lactate, lactic acid, soybean oil and fatty acid. The bacteria converted the different carbon sources supplied into P3HB. The best results were obtained when lactate or soybean oil were supplied as the sole carbon source. The range of number average molar mass (Mn) for the polymers, analyzed by Gel Permeation Chromatography was 1.65 to 0.79 x 10(5) g mol-1. FTIR spectroscopy revealed a characteristic absorbance associated with polyester structures. The crystallinity degree, determinate from X-ray diffractograms, was about 69% in all synthesized polymers. The thermal properties associated to semicrystalline polymers indicated a glass transition at 0.1ºC and a melting point at about 175ºC and enthalpy of 63- 89 J g-1. The ¹H-NMR and 13C-NMR spectra of the polymers were in agreement with the calculated chemical shifts associated with P3HB structures.

Exploring the potential of Burkholderia sacchari to produce polyhydroxyalkanoates

“…2) are compatible with the presence of 3HB and 3HHx in the PHA produced by B. sacchari from glucose and hexanoic acid. The main signals in the 1 H and 13 C NMR spectra for the polymer P3HB-co-3HHx of B. sacchari were consistent with the chemical shifts associated with the structure of P3HB reported in the literature (Valentin et al 1992;Nomura et al 2004;Pereira et al 2008). With respect to the monomer 3HHx, it is possible to verify its presence by the two small signals (one at about 0Á9 ppm and another at about 1Á6 ppm) in the 1 H NMR spectrum ( Fig.…”

“…; Pereira et al . ). With respect to the monomer 3HHx, it is possible to verify its presence by the two small signals (one at about 0·9 ppm and another at about 1·6 ppm) in the 1 H NMR spectrum (Fig.…”

Microbial production of biopolymers from the renewable resource wheat straw

“…The production of bioplastics is based on natural resources, such as glucose, starch and whey (Ahn et al 2000;Kim 2000). Alternative substrates, such as soy bean oil, palm oil and maple sap, are also used in this context (Yezza et al 2007;Pereira et al 2008;Budde et al 2011).…”

“…PHB could also be produced from other substrates, such as lactic acid, soybean oil, fatty acids and glycerol (Pereira et al . ; Ibrahim and Steinbuechel ). The search for alternative or renewable resources is in transition because of the rivalry with food production.…”

“…The use of inexpensive substrates is quite common to make the production economical: substrates such as starch and whey successfully produce PHB (Ahn et al 2000;Kim 2000). PHB could also be produced from other substrates, such as lactic acid, soybean oil, fatty acids and glycerol (Pereira et al 2008;Ibrahim and Steinbuechel 2009). The search for alternative or renewable resources is in transition because of the rivalry with food production.…”