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Effect of mixing rate on β‐carotene production and extraction by dunaliella salina in two‐phase bioreactors
Author(s) -
Hejazi M. A.,
Andrysiewicz E.,
Tramper J.,
Wijffels R. H.
Publication year - 2003
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.10791
Subject(s) - dunaliella salina , extraction (chemistry) , bioreactor , growth rate , mixing (physics) , chromatography , light intensity , chemistry , aqueous two phase system , beta carotene , phase (matter) , chlorophyll , chlorophyll a , carotenoid , food science , analytical chemistry (journal) , botany , biology , biochemistry , algae , organic chemistry , geometry , mathematics , physics , quantum mechanics , optics
β‐Carotene has many applications in the food, cosmetic, and pharmaceutical industries; Dunaliella salina is currently the main source for natural β‐carotene. We have investigated the effect of mixing rate and whether it leads to the facilitated release of β‐carotene from the cells of Dunaliella salina in two‐phase bioreactors. Three pairs of bioreactors were inoculated at the same time, operated at 100, 150, and 170 rounds per minute, respectively, and illuminated with a light intensity of 700 μmol m −2 s −1 . Each pair consisted of one bioreactor containing only aqueous phase for the blank and one containing the water phase together with dodecane, which is biocompatible with the cells. Comparison of the viability and growth of the cells grown under different agitation rates shows that 170 rpm and 150 rpm are just as good as 100 rpm. The presence and absence of the organic phase also has no influence on the viability and growth of the cells. In contrast to the growth rate, the extraction rate of β‐carotene is influenced by the stirrer speed. The extraction rate increases at a higher stirring rate. The effectiveness of extraction with respect to power input is comparable for all the applied mixing rates, even though it is slightly lower for 100 rpm than the others. The chlorophyll concentration in the organic phase remained very low during the experiment, although at higher mixing rates, chlorophyll impurity increased up to 3% (w/w) of the total extracted pigments. At 170 rpm carotenoid and chlorophyll undergo the highest extraction rate for both pigments—0.5% of the chlorophyll and 6% of the carotenoid is extracted. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 84: 591–596, 2003.