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β-Carotene production enhancement by UV-A radiation in Dunaliella bardawil cultivated in laboratory reactors

Paper ID Volume ID Publish Year Pages File Format Full-Text
21750 43238 2009 5 PDF Available
Title
β-Carotene production enhancement by UV-A radiation in Dunaliella bardawil cultivated in laboratory reactors
Abstract

β-carotene is an antioxidant molecule of commercial value that can be naturally produced by certain microalgae that mostly belong to the genus Dunaliella. So far, nitrogen starvation has been the most efficient condition for enhancing β-carotene accumulation in Dunaliella. However, while nitrogen starvation promotes β-carotene accumulation, the cells become non-viable; consequently under such conditions, continuous β-carotene production is limited to less than 1 week. In this study, the use of UV-A radiation as a tool to enhance long-term β-carotene production in Dunaliella bardawil cultures was investigated. The effect of UV-A radiation (320–400 nm) added to photosynthetically active radiation (PAR, 400–700 nm) on growth and carotenoid accumulation of D. bardawil in a laboratory air-fluidized bed photobioreactor was studied. The results were compared with those from D. bardawil control cultures incubated with PAR only. The addition of 8.7 W·m− 2 UV-A radiation to 250 Wm− 2 PAR stimulated long-term growth of D. bardawil. Throughout the exponential growth period the UV-A irradiated cultures showed enhanced carotenoid accumulation, mostly as β-carotene. After 24 days, the concentration of β-carotene in UV-A irradiated cultures was approximately two times that of control cultures. Analysis revealed that UV-A clearly induced major accumulation of all-trans β-carotene. In N-starved culture media, β-carotene biosynthesis in UV-A irradiated cultures was stimulated. We conclude that the addition of UV-A to PAR enhances carotenoid production processes, specifically all-trans β-carotene, in D. bardawil cells without negative effects on cell growth.

Keywords
Carotenoids; Dunaliella bardawil; Photobioreactor; UV-A; β-carotene
First Page Preview
β-Carotene production enhancement by UV-A radiation in Dunaliella bardawil cultivated in laboratory reactors
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Bioscience and Bioengineering - Volume 108, Issue 1, July 2009, Pages 47–51
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering