Simplified two-stage method to B-phycoerythrin recovery from Porphyridium cruentum

A simplified two-stage method for B-phycoerythrin (BPE) recovery from Porphyridium cruentum was developed. The proposed method involved cell disruption by sonication and primary recovery by aqueous two-phase partition. The evaluation of two different methods of cell disruption and the effect of increasing concentration of cell homogenate from P. cruentum culture upon aqueous two-phase systems (ATPS) performance was carried out to avoid the use of precipitation stages. Cell disruption by sonication proved to be superior over manual maceration since a five time increase in the concentration of B-phycoerythrin release was achieved. An increase in the concentration of crude extract from disrupted P. cruentum cells loaded to the ATPS (from 10 to 40%, w/w) proved to be suitable to increase the product purity and benefited the processing of highly concentrated disrupted extract. Kinetics studies of phase separation performed suggested the use of batch settlers with height/diameter (H/D) ratio less than one to reduce the necessary time for the phases to separate. The proposed ATPS stage comprising of 29% (w/w) polyethylene glycol (PEG) 1000g/mol, 9% (w/w) potassium phosphate, tie-line length (TLL) of 45% (w/w), volume ratio (V(R)) of 4.5, pH 7.0 and 40% (w/w) crude extract loaded in a batch settler with H/D ratio of 0.5 proved to be efficient for the recovery of 90% of B-phycoerythrin at the top PEG-rich phase. The purity of B-phycoerythrin increased up to 4.0 times after the two-stage method. The results reported here demonstrate the potential implementation of a strategy to B-phycoerythrin recovery with a purity of 3.2 (estimated by the absorbance relation of 545-280nm) from P. cruentum.