Evaluation of poly(3-hydroxybutyrate) solubility in non-halogenated solvents to achieve an environmentally friendly recovery process from Burkholderia cepacia B27 cells

BACKGROUND Poly(3-hydroxybutyrate) (P3HB) is a biopolymer of bacterial origin widely studied for its physicochemical characteristics, biocompatibility, nontoxicity and biodegradability. Unfortunately, there is no extraction and purification process that allows sustainable large-scale production of the biopolymer. RESULTS The solubility of P3HB in several non-halogenated solvents was studied to achieve a novel and environmentally friendly methodology for polymer solvent extraction from bacterial cells. Acetic acid, ethyl acetate, butyl acetate and methyl ethyl ketone were selected using theoretical approximations for the experimental evaluation of solubility at various temperatures, concentrations and incubation times with a complete general factorial experimental design. The results were interpreted with analysis of variance to evaluate the influence of each factor on the solubility. It was determined that at temperatures above 90 degrees C, acetic acid has a high P3HB solubilization efficiency, which makes it an excellent candidate for an environmentally friendly solvent-extraction process. The mass yield of the extraction process with the new procedure was 54.8% compared to 59.9% for the standard chloroform solvent-extraction process. Also, thermogravimetric analysis and differential scanning calorimetry showed thermal behavior to be similar between P3HB recovered using chloroform and acetic acid extraction. CONCLUSIONS P3HB extraction from Burkholderia cepacia cells using acetic acid extraction and methanol purification is a promising method for large-scale biopolymer production due to the elimination of hazardous solvents from the process. However, polymer purity and yield are slightly affected compared to the conventional chloroform extraction process. (c) 2020 Society of Chemical Industry