title: Enzymatic recovery and purification of polyhydroxybutyrate produced by Ralstonia eutropha.
abstract: Polyhydroxybutyrate (PHB) is the most studied among a wide variety of polyhydroxyalkanoates, bacterial biodegradable polymers known as potential substitutes for conventional plastics. This work aimed at evaluating the use of enzymes to recover and purify the PHB produced by Ralstonia eutropha DSM545. Screening experiments allowed the selection of trypsin, bromelain and lysozyme among six enzymes, based on their efficiency in lysing cells of a non-PHB producing R. eutropha strain. Then, process conditions for high efficiency in PHB purification from the DSM545 cells were searched for the enzymes previously selected. The best result was achieved with 2.0% of bromelain (enzyme mass per biomass), equivalent to 14.1 U ml(-1), at 50 degrees C and pH 9.0, resulting in 88.8% PHB purity. Aiming at improving the process efficiency and reducing the enzyme cost, experiments were carried out with pancreatin, leading to 90.0% polymer purity and an enzyme cost three times lower than the one obtained with bromelain. The molecular mass analysis of PHB showed no polymer degradation. Therefore, this work demonstrates the potential of using enzymes in order to recover and purify PHB and bacterial biopolymers in general.
authors.affiliation: Agrupamento de Biotecnologia-DQ, Instituto de Pesquisas Tecnológicas do Estado de São Paulo-IPT, Cidade Universitaria, Av. Prof. Almeida Prado 532, CEP 05508-901 São Paulo, SP, Brazil. ferkapri@yahoo.com
authors.forename: Fernanda M
authors.initials: FM
authors.lastname: Kapritchkoff
authors.forename: Alexandre P
authors.initials: AP
authors.lastname: Viotti
authors.forename: Rita C P
authors.initials: RC
authors.lastname: Alli
authors.forename: Marisa
authors.initials: M
authors.lastname: Zuccolo
authors.forename: José G C
authors.initials: JG
authors.lastname: Pradella
authors.forename: Alfredo E
authors.initials: AE
authors.lastname: Maiorano
authors.forename: Everson A
authors.initials: EA
authors.lastname: Miranda
authors.forename: Antonio
authors.initials: A
authors.lastname: Bonomi
mesh_terms: D002480:Cellulase / Q000378:metabolism / Q000494:pharmacology; D003470:Culture Media; D020118:Cupriavidus necator / Q000166:cytology / Q000378:metabolism*; D003546:Cysteine Endopeptidases / Q000378:metabolism / Q000494:pharmacology; D004798:Enzymes / Q000378:metabolism* / Q000494:pharmacology; D005069:Evaluation Studies as Topic; D006885:Hydroxybutyrates / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D009113:Muramidase / Q000378:metabolism / Q000494:pharmacology; D011091:Polyesters / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D013997:Time Factors; D000094122:Polyhydroxybutyrates
chemical_list: D002480:Cellulase; D003470:Culture Media; D003546:Cysteine Endopeptidases; D004798:Enzymes; D006885:Hydroxybutyrates; D009113:Muramidase; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates