A novel Bacillus sp. accumulating poly (3-hydroxybutyrate-co-3-hydroxyvalerate) from a single carbon substrate

Abstract

The objective of this paper was to report a bacterium designated as 88D, capable of producing poly (3-hydroxybutyrate-co-3-hydroxyvalerate) [P (3HB-co-3HV)] copolymer from a single carbon source, which was isolated from a municipal sewage treatment plant in Hyderabad, India. This microorganism, based on the phenotypical features and genotypic investigations, was identified as Bacillus sp. The optimal growth of Bacillus sp. 88D occurred between 28 and 30 degrees C and at pH 7. The strain yielded a maximum of 64.62% dry cell weight (DCW) polymer in the medium containing glucose as carbon source, which was followed by 60.46% DCW polymer in glycerol containing medium. Bacillus sp. 88D produced P (3HB-co-3HV) from glucose or glycerol, when they were used as a single carbon substrate. This bacterium produced polyhydrxybutyrate (PHB) when sodium acetate was used as sole carbon substrate. The viscosity average molecular mass (Mv) of the copolymers ranged from 523 to 627 kDa. The physical, chemical and mechanical properties of the biopolymers were characterized.

Effects of Aeration on the Synthesis of Poly(3-Hydroxybutyrate) from Glycerol and Glucose in Recombinant Escherichia coli

“…A recent study performed using C. necator describes PHB obtained from commercial glycerol and from waste glycerol with a molecular mass of 957 and 786 kDa, respectively, less than half of that of PHB obtained from glucose (4). In contrast, in a recent report describing PHB-[poly(3-hydroxyvalerate)] (PHB-PHV) accumulation in a Bacillus strain, similar molecular masses, lower than 700 kDa, were observed for the polymer obtained from the two carbon sources (18).…”

“…Its use for microbial PHA synthesis has been analyzed for natural PHA producers, such as Methylobacterium rhodesianum, Cupriavidus necator (formerly called Ralstonia eutropha) (3), several Pseudomonas strains (22), the recently described bacterium Zobellella denitrificans (7), and a Bacillus sp. (18), among others. Glycerol has also been used for PHB synthesis in recombinant E. coli (12,15).…”

Making Green Polymers Even Greener:Towards Sustainable Production of Polyhydroxyalkanoates from Agroindustrial By-Products

“…A recent study performed using R. eutropha describes PHB obtained from commercial glycerol and www.intechopen.com Making Green Polymers Even Greener: Towards Sustainable Production of Polyhydroxyalkanoates from Agroindustrial By-Products 47 from waste glycerol with a M r of 957 and 786 kDa, respectively, less than half of that of PHB obtained from glucose (Cavalheiro et al, 2009). In contrast, in a recent report describing P(HB-co-HV) accumulation in a Bacillus strain, similar M r s, lower than 700 kDa, were observed for the polymer obtained from the two carbon sources (Reddy et al, 2009). A low M r is undesirable for industrial processing of the polymer, so the results available in the literature pointed to a drawback in the use of glycerol as a substrate for the microbial production of PHAs.…”

Biodiesel Industry Waste: A Potential Source of Bioenergy and Biopolymers

“…Bioplastics (PHAs) have emerged as a promising alternative to synthetic plastics [18,49,50]. Although microbes are well known for their biotechnological applications, they are also known to accumulate biopolymers (PHA) as food reserves [51][52][53]. Production of PHA is influenced by the type of feed (pure substrates as well as biowastes) and the organism used [44].…”

“…have been found to be efficient producers of PHA [18,50,62,63]. With glycerol as feed, Bacillus megaterium has been able to utilize 2-5 % feed to produce 31-62 % w/w PHA [49,[51][52][53]. Bacillus thuringiensis has been reported as the highest PHA producer with a capacity of 64.1 % (w/w) at 1 % PG (Table 3) [54].…”