Identification of carotenoids from the extremely halophilic archaeon Haloarcula japonica

Abstract

The carotenoids produced by extremely halophilic archaeon Haloarcula japonica were extracted and identified by their chemical, chromatographic, and spectroscopic characteristics (UV-Vis and mass spectrometry). The composition (mol%) was 68.1% bacterioruberin, 22.5% monoanhydrobacterioruberin, 9.3% bisanhydrobacterioruberin, <0.1% isopentenyldehydrorhodopin, and trace amounts of lycopene and phytoene. The in vitro scavenging capacity of a carotenoid, bacterioruberin, extracted from Haloarcula japonica cells against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals was evaluated. The antioxidant capacity of bacterioruberin was much higher than that of β -carotene.

Complete Biosynthetic Pathway of the C50Carotenoid Bacterioruberin from Lycopene in the Extremely Halophilic Archaeon Haloarcula japonica

“…3A, peak 1), MABR (peak 2), BABR (peak 3), IDR (peak 4), and lycopene (peak 5), respectively, in our previous study (Fig. 3 and Table 3) (22). In contrast, only one carotenoid (Fig.…”

“…BR, which contains 13 conjugated double bonds and four hydroxyl groups, is regarded to be an effective free-radical scavenger. Our previous study has shown that the free-radical scavenging capacity of BR is much higher than that of ␤-carotene, which contains 11 conjugated double bonds (22). Moreover, BR is a dipolar C 50 carotenoid, and it was suggested to act as a "rivet" in the cell membrane, to increase its rigidity and mechanical strength (7).…”

“…In our previous study, we found that Ha. japonica can produce isopentenyldehydrorhodopin (IDR; C 45 ), bisanhydrobacterioruberin (BABR; C 50 ), and monoanhydrobacterioruberin (MABR; C 50 ) as intermediates and that BR is produced as the final product (22). In addition, it has been suggested that Ha.…”

Biocompounds from Haloarchaea and Their Uses in Biotechnology

“…Among natural pigments, carotenoids are of high interest due to their biotechnological applications and their potential beneficial effects on human health [17][18][19]. These compounds are the second most abundant naturally occurring pigments in nature ranging from colorless to yellow, orange, and red [20,21]. The production of these pigments has been described in plants and some microorganisms such as algae, cyanobacteria, yeast, and fungi [22,23].…”

“…Few years later, it was described that bacterioruberin is in general synthesized from other C 50 carotenoids, such as isopentenyldehydrorhodopin, bisanhydrobacterioruberin, and monoanhydrobacterioruberin [21]. The synthesis is induced by (i) low oxygen tension and high light intensity [34,35]; (ii) osmotic stress [36]; and (iii) the presence of different compounds such as aniline (Figure 1) [37].…”