Abstract:
Development of isolation and purification processes of biodegradable P(3HB) produced by Bacillus megaterium BA-019 was studied. Uses of inexpensive chemicals, in efficient and simple methods were investigated in order to enhance efficiency of the isolation and purification of P(3HB). Bacterial cells were obtained by cultivating in mineral salt medium (MSM) for 24 h. The content of P(3HB) was determined by gas chromatography. Comparison of using dried cells and wet cells were carried out. The best method of isolation and purification of P(3HB) from dried cells was by incubating the cells with 0.1 M sodium chloride, at 30ºC, agitation at 200 rpm. for 3 h, followed by cell disruption with 0.1 M sodium hydroxide, incubated at 30ºC, agitation at 200 rpm. for 1 h. The product was then polished with cold ethanol 20% v/v. The purity and recovery were 88.30% and 96.31% by weight, respectively. The molecular weight (Mw) of P(3HB) obtained by this method was 263,766 Da. The best method of using wet bacterial cells for isolation and purification of P(3HB) was mechanical cell disruption using 5% (w/v) LAS-99, followed by ultrasonication at 40% amplitude for 10-20 minutes. After polished with cold ethanol 20% v/v, the purity and recovery were 95.27% and 99.01% by weight, respectively with Mw of 88,844 Da. The Mw of P(3HB) that isolated and purified by the developed method was lower than that the conventional method which chloroform was used as an organic solvent that was 313,873 Da. The percentage of purity and recovery of P(3HB) obtain by the developed method in this work was higher than that obtained by the conventional method.