Biosynthesis of a novel C30 carotenoid in Bacillus firmus isolates

Abstract

Aims Pigmented Bacillus spp. with probiotic properties have been isolated. In the yellow‐/orange‐coloured strains, the carotenoid pigments present have been characterized. In contrast, the carotenoids present in the Bacillus isolates coloured red await identification. The present article reports progress on the elucidation of the pigment biosynthetic pathway in these red‐pigmented Bacillus firmus strains. Methods and Results A combination of UV/Vis, chromatographic and mass spectrometry (MS) has revealed the properties of the predominant pigment and the end‐point carotenoid of the pathway to be methyl 4,4′‐diapolycopene‐dioate after transmethylation. The diglycosyl ester of 4,4′‐diapolycopene‐dioate persists in vivo prior to chemical treatment. Different mutants and inhibitor treatment were employed to establish the C30 biosynthesis pathway with all precursors and intermediates to 4,4′‐diapolycopene‐dioate detected, which include 4,4′‐diapophytene and all desaturation intermediates to 4,4′‐diapolycopene and 4,4′‐diapolycopene‐dialdehyde. To cultures synthesizing the 4,4′‐diapolycopene‐dioate derivative and those in which its formation was inhibited, oxidative stress was induced by peroxide treatment. Conditions that decreased the growth rate of the pigmented cells by only 30% caused a complete growth inhibition of the culture devoid of the 4,4′‐diapolycopene‐dioate derivative. Conclusion This finding demonstrates the diversity of C30 carotenoid biosynthesis in Bacillus species and the antioxidative function of the 4,4′‐diapolycopene‐dioate derivative in B. firmus cells. Significance and Impact of the Study It could be shown that the C30 4,4′‐diapolycopene‐dioate derivatives protect pigmented B. firmus from peroxidative reactions. Under oxidative conditions, this can be an ecological advantage over nonpigmented (=noncarotenogenic) strains that are equally abundant.

Role and Function of LitR, an Adenosyl B 12 -Bound Light-Sensitive Regulator of Bacillus megaterium QM B1551, in Regulation of Carotenoid Production

“…The ability of Bacillus spp. to produce carotenoids has been reported previously (23)(24)(25)(26)(27); however, the correlation between carotenoid production and light has not been investigated in this genus. In our screen of lightresponsive bacteria (see Materials and Methods), the strains isolated from soil were identified as B. megaterium, B. sphaericus, and B. pumilus by 16S rRNA gene-based phylogenetic analysis.…”

Aryl Polyenes, a Highly Abundant Class of Bacterial Natural Products, Are Functionally Related to Antioxidative Carotenoids

“…Peroxidation experiments were carried out with the wild type and the W5 white mutant of V. paradoxus B4 in LB medium. Cultures (2 days old) were diluted to an OD 600 of 0.01, and peroxidation experiments were started by application of cumene hydroperoxide dissolved in acetone . Growth was determined after 24 h. Mean values and standard deviations were calculated from three independent experiments.…”

Pigmentation and Sporulation Are Alternative Cell Fates in Bacillus pumilus SF214

“…In non-photosynthetic organisms pigments have been associated to cell resistance to UV irradiation and reactive oxygen species [21], [22], [23]. To analyze the role of the SF214 pigment we isolated an unpigmented mutant after nitrosoguanidine (NTG) mutagenesis [32] (Fig.…”

“…Isolates of several Bacillus species produce a wide variety of pigments, from spore-associated melanin-like molecules [19] to different types of carotenoids [20], [21]. In some cases, those carotenoids have been characterized and proposed to provide resistance to UV irradiation and reactive oxygen species [20], [21], [22], [23]. A pigmented strain of Bacillus pumilus , SF214, isolated from a marine sample, has been previously described [21].…”