Effect of Soap Saponification Level on PHB Digestion Isolation from Biomass

Poly(3-hydroxybutyrate) (P3HB) is a biopolymer with a significant potential to substitute used petroleum-based compounds in various material segments. This article focuses on the vegetable oil soap quality affecting the surfactant digestion method for polyhydroxybutyrate (PHB) isolation from crude biomass. We produced fully saponified oil and unsaponified oil, displaying two approaches to gain amphiphilic compounds appropriate for the digestion of P3HB isolation through the cell disruption principle. This comparison represents an essential factor in process upscale─the reduction of energy consumption. We analyzed the saponified vegetable oil and the postreaction extract via volumetry, gravimetry, and Fourier transform infrared (FTIR). The saponified oil contained less than 5 wt % nonsoap extract, while the unsaponified oil comprised 20 wt % unreacted triacylglycerides. The following P3HB digestion isolation uncovered that both yield (saponified oil P3HB yield: >99%, unsaponified oil P3HB yield: 40%) and purity (saponified oil P3HB purity: >99%, unsaponified oil P3HB purity: 86%) significantly favored completely saponified oil. The molecular weight analysis discovered higher Mw values of P3HB from saponified oil (539 000 g/mol) than from unsaponified oil (469 000 g/mol) digestion. The processability of the isolated polymer was verified only for P3HB from saponified oil digestion.