title: Selective extraction of carotenoids from the microalga Dunaliella salina with retention of viability.
abstract: Simultaneous production and selective extraction of beta-carotene from living cells of Dunaliella salina in a two-phase system of aqueous and organic phases has been investigated. Solvents with values of log P(octanol), which denotes hydrophobicity of a compound, ranging from 3 to 9 were used as organic phase. Viability and activity of Dunaliella salina in the presence of organic solvents were checked by microscopic observation and photosynthetic oxygen-production-rate measurements, respectively. Extraction ability of different solvents for both beta-carotene and chlorophyll was determined spectrophotometrically. In addition, beta-carotene contents of the cells growing in the aqueous phase and extracted beta-carotene by the different organic phases were quantified by the same method. Results showed that solvents having log P(octanol) > 6 can be considered biocompatible for this alga. Moreover, pigment extraction ability of a solvent is inversely dependent on its log P(octanol) value. By increasing the degenerative hydrophobicity the extraction ability for both chlorophyll and beta-carotene, decreases. However, this decrease is more profound for chlorophyll. Therefore, selective extraction of beta-carotene becomes feasible. Comparison of the total beta-carotene produced in the presence and in the absence of solvents shows that the presence of a second phase of biocompatible solvents in the culture media may induce the beta-carotene production pathway. The beta-carotene productivity per cell in a two-phase system with dodecane was the highest observed. Extraction ability of the biocompatible solvents dodecane, tetradecan, and hexadecane was similar.
authors.affiliation: Food and Bioprocess Engineering Group, Wageningen University, Wageningen, The Netherlands. mohamin.hejazi@algemeen.pk.wau.nl
authors.forename: M A
authors.initials: MA
authors.lastname: Hejazi
authors.forename: C
authors.initials: C
authors.lastname: de Lamarliere
authors.forename: J M S
authors.initials: JM
authors.lastname: Rocha
authors.forename: M
authors.initials: M
authors.lastname: Vermuë
authors.forename: J
authors.initials: J
authors.lastname: Tramper
authors.forename: R H
authors.initials: RH
authors.lastname: Wijffels
mesh_terms: D002338:Carotenoids / Q000302:isolation & purification* / Q000378:metabolism*; D002470:Cell Survival; D005591:Chemical Fractionation / Q000379:methods*; D000460:Chlorophyta / Q000502:physiology*; D009930:Organic Chemicals / Q000737:chemistry*; D012996:Solutions; D012997:Solvents / Q000737:chemistry*
chemical_list: D009930:Organic Chemicals; D012996:Solutions; D012997:Solvents; D002338:Carotenoids