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 degrees C, 125 rpm, biomass/digestion solution (100 g/L) = 1/10 (w/v) and 10 min) and the second-stage used NaOH method (50 degrees C, 125 rpm, biomass/digestion solution (1 M) = 1/10 (w/v) and 10 min). Crown Copyright (C) 2010 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.