Effects of cell fermentation time and biomass drying strategies on the recovery of poly-3-hydroxyalkanoates from Alcaligenes eutrophus using a surfactant-chelate aqueous system

In the course of poly-3-hydroxyalkanoate (PHAs) recovery from Alcaligenes. eutrophus by a surfactant and chelate: method, a number of operating parameters. in addition to dosage of chemical agents, temperature and pH, might influence recovery results. The effects of cell culture time and drying strategy were investigated on poly-3-hydroxybutyrate: (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) recovery. Increasing fermentation time was confirmed to benefit PHB/PHBV accumulation and recovery, but at the late fermentation, both the PHB/PHBV content and the recovered product purity were not clearly enhanced with the increased culture time. Experiments also indicated that the wet or 60 degrees dried biomass could be utilized to recover PHB and PHBV. but the purity and molecular weight of the product were lower than using the lyophilized. By employing one of the following tactics (increasing the surfactant dose, raising the pH, increasing the temperature or lengthening the treatment time), the purity of recovered PHB/PHBV was significantly improved, which suggested another energy-saving strategy for drying biomass instead of freeze drying. (C) 2001 Elsevier Science Ltd. All rights reserved.