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Characterization of cyanobacterial β‐carotene ketolase and hydroxylase genes in Escherichia coli , and their application for astaxanthin biosynthesis
Author(s) -
Scaife Mark A.,
Burja Adam M.,
Wright Phillip C.
Publication year - 2009
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.22330
Subject(s) - astaxanthin , carotenoid , escherichia coli , carotene , biosynthesis , gene , biochemistry , biology , chemistry , food science
Abstract Carotenoid biosynthesis is highly conserved and well characterized up to the synthesis of β‐carotene. Conversely, the synthesis of astaxanthin from β‐carotene is less well characterized. Regardless, astaxanthin is a highly sought natural product, due to its various industrial applications and elevated antioxidant capacity. In this article, 12 β‐carotene ketolase and 4 β‐carotene hydroxylase genes, isolated from 5 cyanobacterial species, are investigated for their function, and potential for microbial astaxanthin synthesis. Further, this in vivo comparison identifies and applies the most promising genetic elements within a dual expression vector, which is maintained in Escherichia coli . Here, combined overexpression of individual β‐carotene ketolase and β‐carotene hydroxylase genes, within a β‐carotene accumulating host, enables a 23.5‐fold improvement in total carotenoid yield (1.99 mg g −1 ), over the parental strain, with >90% astaxanthin. Biotechnol. Bioeng. 2009;103: 944–955. © 2009 Wiley Periodicals, Inc.