Simplified recovery process of Ralstonia solanacearum-synthesized polyhydroxyalkanoates via chemical extraction complemented by liquid-liquid phase separation

Abstract

Poly (3-hydroxybutyrate) (P(3HB)) is the most studied thermoplastic biopolymer belonging to the polyhydroxyalkanoate (PHA) family, the main features of which include rapid biodegradability and biocompatibility. The bioplastic recovery process is an important step during production and can directly influence the characteristics of PHAs. However, more efficient methods for the production of P(3HB) are necessary to make it economically viable. The aim of the present study was to improve the standard, chloroformbased, extraction step for the recovery of P(3HB). The polymer was produced using a Ralstonia solanacearum strain. The following parameters were improved in the recovery process: heating time, separation method (filtration or liquid-liquid phase separation), biomass state (fresh or dry cell concentrate) and the solvent:biomass ratio. By improving the chemical extraction of P(3HB) we recovered 98% of the cumulative polymer and reduced the heating time by 75%. Furthermore, we improved the separation process and developed an extraction solution that was faster and more economical.

Optimization of Ralstonia solanacearum cell growth using a central composite rotational design for the P(3HB) production: Effect of agitation and aeration

“…The average molar mass (Mm) of P(3HB) produced by R . solanacearum RS strain was 2.9 × 10 5 Da [23]. This property is extremely important because it directly affects the mechanical strength of the bioplastics as well as the expansion capacity, the hydrolysis, and consequently, the biodegradation rate [42].…”

“…The P(3HB) accumulation was determined by chemical extraction using a method that allows recovery up to 98% of accumulated polymer[23]. To calculate the accumulation yield, the samples were weighed, and the results were expressed as a percentage, according to Eq 1.…”

Biodegradative capacity of Bacillus megaterium and Ralstonia solanacearum on biodegradation of P(3HB) films in simulated soil

“…Plastics derived from petrochemical sources are highly consumed in today's society due to its wide range of uses, from the manufacture of surgical instruments to the production of disposable packages. However, due to their mechanical properties of integrity and durability, they present prolonged degradation time (Alves et al, 2017). In order to minimize the environmental impacts caused by these plastics, several European Union countries such as the Netherlands and Belgium have already adopted policies to discourage their use, the same is reported for the cities of Ladakh in India, Dhaka in Bangladesh and South Australia, where its use is prohibited (Chanprateep, 2010).…”

“…To replace these plastics, biodegradable polyesters such as polyhydroxyalkanoates (PHA)s, with wide production worldwide, are strong candidates. One of the most researched PHAs is the poly(3-hydroxybutyrate) [P(3HB)], a biocompatible, biodegradable and thermoplastic material that can be used in several industrial areas such as the manufacture of disposable utensils, medical materials and drug delivery (Alves et al, 2017;Raza et al 2018).…”

“…Those, in a microbiologically active environment, shown effectively degradation in months compared to conventional plastics, which takes years (Boyandin et al, 2011;Altaee et al, 2016;Alves et al, 2017), resulting as final products carbon dioxide (CO2), water (H2O) in O2 presence and methane (CH4) under anaerobic conditions (Wang et al, 2013;Wang et al, 2014).…”