COMPARISON AND OPTIMIZATION OF POLY(3-HYDROXYBUTYRATE) RECOVERY FROM ALCALIGENES-EUTROPHUS AND RECOMBINANT ESCHERICHIA-COLI

The recovery of poly(3-hydroxybutyrate) [PHB] from Alcaligenes eutroph us and a recombinant Escherichia coli strain harboring the A. eutrophu s poly(3-hydroxyalkanoates) biosynthesis genes was studied. When PHB w as recovered using sodium hypochlorite or sodium dodecyl sulfate (SDS) , non-PHB cell materials (NPCM) of the recombinant E. coil seemed to b e more easily digested than those of A. eutrophus. Furthermore, viscos ity increase caused by cell lysis during SDS treatment was negligible for the recombinant E. coli, whereas a very viscous suspension was for med for A. eutrophus. These results, together with our previous findin g that PHB in the recombinant E. coli is far less susceptible to molec ular degradation by sodium hypochlorite, suggested that the recombinan t E. coli was more beneficial than A. eutrophus in terms of PHB recove ry. In order to develop an easy and efficient recovery process, we ado pted and optimized the SDS treatment since, with the hypochlorite trea tment, we could not handle high biomass concentrations effectively. We could obtain a PHB of 95 % purity with 96 % recovery under the optima l condition of a biomass concentration of 5 %, a ratio of SDS to bioma ss of 0.6, a treatment time of 60 minutes, and a treatment temperature of 30 degrees C.