The present study developed an efficient and environmentally friendly method for recovering polyhydroxybutyrate (PHB) from Cupriavidus necator. Several non-halogenated solvents were tested and it was found that butyl acetate and ethyl acetate are powerful solvents for the biopolymer. Testing was performed to examine the effects of temperature (25 °C until temperature below solvent boiling points) and heating incubation time (0-60 min) on the two solvents. Butyl acetate had a higher recovery level (96%) and product purity (up to 99%) than ethyl acetate at 103 °C and a heating incubation time of 30 min. Under these conditions, PHB recorded the highest molecular weight of 1.4 × 10(6) compared with the standard procedure (i.e., recovery using chloroform). The proposed strategy showed that butyl acetate is a good alternative to halogenated solvents such as chloroform for recovery of PHB.

No abstract

There are many published studies presenting ethanol and acetone as PHAs-poor solvents, where these two solvents are shown to dissolve <2% (w/v) of PHAs at low temperatures. In this study, the suitability of ethanol and acetone for the recovery of PHB at different temperatures (from room temperature to near boiling point) in Cupriavidus necator was investigated. Experiments were performed using response surface methodology to examine the effects of different temperatures and heating incubation times on recovery percentage using the two solvents. The highest recovery percentage (92.3%) and product purity (up to 99%) were obtained with ethanol-assisted extraction at 76°C for 32 min of incubation time. Under these conditions the extracted PHB exhibited a molecular mass of 1.2 × 10 . The present strategy showed that at temperatures near its boiling point, ethanol, as a nonhalogenated solvent, represents a good alternative to halogenated solvents, like chloroform, when PHB recovery is concerned. DSC analysis showed good thermal properties for ethanol- and acetone-extracted biopolymers. GC and H NMR analysis confirmed the extracted biopolymer to be polyhydroxybutyrate of good purity. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1480-1486, 2016.