beta-carotene and decane

Improving productivity is a usual requirement for most biotechnological processes, and the utilisation of two-phase aqueous organic systems has proved to be an effective way to improve the productivity of poorly water-soluble or toxic compounds. The high hydrophobicity of beta-carotene, which is highly demanded by the pharma and agrofood industry, makes it a good candidate for aqueous/organic biphasic photoproduction. In the present work we have investigated the viability of a two-phase system for the production of beta-carotene by the marine microalgae Dunaliella salina using decane as organic phase. Decane, with a logP(octanol) value of 5.6, showed no toxicity to Dunaliella cells for more than 72 h, and its ability for beta-carotene extraction is acceptable. Transferring Dunaliella cells from standard to carotenogenic conditions caused inhibition of chlorophyll production and induced a strong synthesis of beta-carotene. The two-phase aqueous/decane system was stable and beta-carotene content of the cells was increasing during 4-days. About 8% of the total carotenoids produced were excreted and extracted into the decane phase.

Topics: Adaptation, Physiological; Alkanes; beta Carotene; Bioreactors; Cell Culture Techniques; Cell Division; Cell Survival; Chlorophyll; Chlorophyta; Dose-Response Relationship, Radiation; Light; Phase Transition; Radiation Dosage; Solvents; Water

The effect of oxygen partial pressure and solvent on the kinetics of beta-carotene consumption and oxygen uptake in the course of beta-carotene oxidation has been studied. The reaction of free radical formation, i.e., the chain initiation reaction that occurs via interaction of beta-carotene with oxygen and chain branching reactions that occur via interaction of intermediate products with oxygen, are found to be the most sensitive to the effect of environmental factors. These reactions determine the dependence of the beta-carotene consumption and oxygen uptake rates on oxygen partial pressure. The reaction rates increase in polar solvents which causes the increase in the beta-carotene consumption and oxygen uptake rates. The rates of peroxyl radical destruction and/or isomerization increase in polar media, which leads to the formation of low molecular weight polar oxidation products.

Topics: Alkanes; beta Carotene; Chlorobenzenes; Cyclohexenes; Free Radicals; Kinetics; Limonene; Lipids; Models, Chemical; Nitriles; Oxygen; Partial Pressure; Terpenes