Polyhydroxyalkanoate Synthesis by Recombinant Escherichia coli JM109 Expressing PHA Biosynthesis Genes from Comamonas sp. EB172

Abstract

Recombinant Escherichia coli JM109 harbouring the polyhydroxyalkanoate (PHA) biosynthesis gene (phaCABco) of Comamonas sp. EB172, an acid tolerant microbe, was examined for the production of PHAs from various carbon sources. The study demonstrated that the recombinant E. coli JM109 had the potential to utilize both sugar-and acid-based carbon sources, for the biosynthesis of both poly(3-hydroxybutyrate) P(3HB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) P(3HB-co-3HV) copolymers. In the shake flask experiments, the strain was capable of producing P (3HB-co-3HV) copolymer from mixed organic acids, and higher productivities were obtained using glucose compared to mixed acids. However, PHA accumulation was found to be similar, regardless of the carbon source used. Nitrogen supplementation in the medium was found to improve the cell dry weight, but negatively affected the 3HV formation in copolymer production. Maximum 3HV monomer (3 mol%) was obtained with C/N 42.1, using mixed acids as the carbon source. In the 2L bioreactor, the productivity and yield based on substrate utilization coefficient were found to be 0.16 g PHA/(L.h) and 0.41 g PHA/g substrate under C/N around 75, using 20 g/L glucose and 0.5 g/L ammonium sulphate, respectively. The polymer produced by the recombinant strain had molecular weight in the range of 8.5 x 105 to 1.4 x 106 Da. Overall, the ability of the recombinant E. coli JM109 to utilize both glucose and mixed acids, has widened its substrate selection for fermentation, including the opportunity to use renewable biomass.

Two-Stage Polyhydroxyalkanoates (PHA) Production from Cheese Whey Using Acetobacter pasteurianus C1 and Bacillus sp. CYR1

“…Alternatively, high PHA-producing strains were engineered to express lactose degradation genes [ 57 ]. Recombinant E. coli has commonly been employed for PHA production due to its convenience for genetic manipulation, fast growth, high cell density cultivation, and its ability to utilize inexpensive carbon sources [ 58 ]. Therefore, the development of recombinant E. coli will be one of the applicable methods to improve PHA production.…”

Production and applications of crude polyhydroxyalkanoate-containing bioplastic from the organic fraction of municipal solid waste

“…Different agricultural wastes can be used for this purpose through chemical or enzymatic hydrolysis (Du et al 2012;Sandhya et al 2013). Mono-and disaccharides can be used for the production of PHAs mainly in aseptic cultivation because it is possible to select strains of bacteria (Du et al 2012;Vishnuvardhan and Thirumala 2012;Yee et al 2012) or yeasts (Abd-El-Haleem et al 2007) with low production of storage carbohydrates under excess of carbon and energy source. Meanwhile, the wild strains of microorganisms in non-aseptic mixed culture will transform excess of external sugars to the glycogen, exopolysaccharides, or lipids (Ivanov 2010).…”

Polyhydroxy alkanoates Production by Newly Isolated Bacteria Serratia ureilytica Using Volatile Fatty Acids as Substrate: Bio-Electro Kinetic Analysis

“…These bacteria can utilize urea as a sole nitrogen source for its growth and has the ability to hydrolyze urea to ammonia [31]. Ye et al (2012) reported 37% production of PHA using mixed volatile fatty acids recombinant Escherichia coli [32].…”