Sunday, August 12, 2012
Columbia Hall, Terrace Level (Washington Hilton)
Safety concerns, related to the increasing application of synthetic colouring agents, have generated an increased demand for natural colorants. Fungi have been employed for production of novel and safer colorants. In order to obtain the colorants, from fermented broth (FB), suitable extraction systems must be developed. Aqueous two-phase systems (ATPS) can offer the right chemical environment for the natural colorants. The aim of this study was to investigate the partitioning of red colorants (RC) from FB of Penicillium purpurogenum in ATPS composed by poly(ethylene glycol)(PEG) and sodium polyacrylate(NaPA). The ATPS was formed by mixing both polymers, each at 12%, with a salt (NaCl or Na2SO4 at 0.1 or 0.5M) and the FB. The presence of RC in each phase was evaluated through the measurement of the absorbance at 490nm. The following PEG-molecular size: 1000, 6000 and 10000g/mol on RC recovery was investigated. Higher RD recovery was obtained with PEG6000 and 10000g/mol than with 1000g/mol. The best partition coefficient, K, and selectivity (Se) in relation to proteins, results were obtained with PEG6000 and NaCl0.1M, 13.06 and 3.05, respectively. With PEG10000g/mol the best result was obtained with Na2SO4 0.5M, as follows: K=12.11 and Se=2.61. For both polymers the mass balance and recovery was close to 100 and 90%, respectively. These results indicate that the partitioning depends on salt type and PEG-molecular size. In conclusion, the results above show that ATPS is a promising separation method which can be used as the first step of purification for the recovery of RC from FB.