Biotechnological strategies to improve production of microbial poly‐(3‐hydroxybutyrate): a review of recent research work

Abstract

Poly-(3-hydroxybutyrate) [P(3HB)] is a polyester synthesized as a carbon and energy reserve material by a wide number of bacteria. This polymer is characterized by its thermo-plastic properties similar to plastics derived from petrochemical industry, such as polyethylene and polypropylene. Furthermore, P(3HB) is an inert, biocompatible and biodegradable material which has been proposed for several uses in medical and biomedical areas. Currently, only few bacterial species such as Cupriavidus necator, Azohydromonas lata and recombinant Escherichia coli have been successfully used for P(3HB) production at industrial level. Nevertheless, in recent years, several fermentation strategies using other microbial models such as Azotobacter vinelandii, A. chroococcum, as well as some methane-utilizing species, have been developed in order to improve the P(3HB) production and also its mean molecular weight.

Challenges and Opportunities for Customizing Polyhydroxyalkanoates

“…from 47 to 16 mol% [72]. Along with this, M w is strongly affected by aeration conditions and improved from 14.8 9 10 2 to 16.7 9 10 2 kDa with increase in the aeration rate from 250 to 190 rpm [77]. Cultivation time of the reactor is also observed to alter the monomers.…”

C1-carbon sources for chemical and fuel production by microbial gas fermentation

“…A variety of different PHA polymers have been synthesized by cofeeding of various substrates or by metabolic engineering approaches [21 ,24]. These natural PHAs are inert and have thermoplastic or elastomeric properties, are decomposed in nature by microorganisms and thus are promising materials as biocompatible and biodegradable plastic for many applications in the chemical industry and in medical and pharmaceutical fields [24,[25][26][27]. Under autotrophic and oxygen-limited (<6.9%, v/v) growth conditions, R. eutropha has been shown to accumulate up to 61.9 g PHB l À1 within 40 h with a productivity of 1.55 g l À1 h À1 [19].…”

Biodegradable polymeric nanomaterials

“…To reduce its crystallinity and result in materials with better processability, as well as to increase its degradation rate, PHB is often copolymerised with 3-hydroxyvaleric acid (HV). PHB and P(HB-HV) may find applications as tissue engineering scaffolds and drug delivery nanoparticles [20].…”