Isolation and Purification of Medium Chain Length Poly(3-hydroxyalkanoates) (mcl-PHA) for Medical Applications Using Nonchlorinated Solvents

Abstract

A novel process was developed to isolate poly([R]-3-hydroxyoctanoate-co-3-hydroxyhexanoate) (PHO) and poly([R]-3-hydroxy-ω-undecenoate-co-3-hydroxy-ω-nonenoate-co-3-hydroxy-ω-heptenoate) (PHUE) from Pseudomonas putida species. Methyl tert-butyl ether (MTBE), ethyl acetate, acetone, and methylene chloride efficiently extracted PHO from freeze-dried biomass. The ratio of solvent to biomass was 15:1 (vol/wt). The nonchlorinated solvents required 18 h of extraction to achieve methylene chloride's yield of 15 wt % within 60 min. In the case of PHUE, the yield was 15-17 wt % after 60 min of extraction at room temperature, independently of the solvent used. MTBE performed best in life cycle assessment (LCA) if contamination of the environment is avoided. Filtration of the extract containing 8 wt % of raw polyhydroxyalkanoate (PHA) through activated charcoal revealed colorless polymers with less than one endotoxin unit/g. The ratio (v/v) of the solution to activated charcoal was 2:1. The loss (impurities and polymers) amounted up to 50 wt %.

A reduction in growth rate of Pseudomonas putida KT2442 counteracts productivity advances in medium-chain-length polyhydroxyalkanoate production from gluconate

“…PHA contents lower than 5 wt % were considered to negligible and the detected monomers to arise from cell membrane components. Indeed no PHA could be extracted [39,40] from the biomass of P. putida KT2440 cultivated on citrate with a C/N ratio of 15 g g -1 although 5.1 wt % "PHA" were detected by GC (data not shown).…”

Start a Research on Biopolymer Polyhydroxyalkanoate (PHA): A Review

“…LPS endotoxin is a pyrogen which can elicit a strong inflammatory response [102], rendering the PHA polymer unsuitable for biomedical applications. Removal of LPS endotoxin can be achieved through the treatment of PHA polymer with oxidizing agents (i.e., sodium hypochlorite and NaOH, ozone, hydrogen peroxide, and benzoyl peroxide), with repeated solvent extractions, or with solvent extraction followed by purification with activated charcoal [7,103,104]. These methods however, increase the overall cost of PHA production and lead to changes in PHA polymer properties (i.e., reduction in molecular mass and polydispersity).…”

Isolation and recovery of microbial polyhydroxyalkanoates

“…This is comparable to the values obtained from chloroform extraction (94% yield and 98% purity). For the extraction of mcl-PHA, methyl tert-butyl ether (MTBE) has been evaluated and the extractability was found to be promising as in the case with chlorinated-solvents [26]. Wampfler et al [26] claimed that MTBE would have lower environmental impact if the recovery of PHA as well as the production and recycling of MTBE could be carried out in closed facilities.…”