High throughput study of separation of poly(3-hydroxybutyrate) from recombinant Escherichia coli XL1 blue

Polyhydroxyalkanoates (PHAs) are biodegradable plastics. Currently most PHAs are produced using microbial fermentation. The separation of PHAs is a key factor in the design of a successful production scheme. This study chose a recombinant Escherichia coli to produce poly(3-hydroxybutyrate) (PHB), an important one among PHAs; and to use different separation methods to recover PHB. The diversity of PHB obtained by different separation methods was characterized. Among different methods used, sodium dodecyl sulfate (SDS)–NaOH method was selected as the best in separation from the results obtained from experiments using a combinatorial design. In the combinatorial design, only 16 runs are needed to generate 150 sets of experimental data. By using a two-stage design, PHB with a purity of 99% was obtained when the first-stage digestion used SDS digestion method (50 °C, 125 rpm, biomass/digestion solution (100 g/L) = 1/10 (w/v) and 10 min) and the second-stage used NaOH method (50 °C, 125 rpm, biomass/digestion solution (1 M) = 1/10 (w/v) and 10 min).