pigmented alkaliphilic Bacillus sp. [1]. A lycopene type of carotenoid pigment was
produced by alkaliphilic Microbacterium arborescens AGSB, obtained from coastal
sand dunes. Novel carotenoid glucoside esters have been reported from alkaliphilic
Heliobacteria [62]. Later, the same type of carotenoid, OH-diaponeurosporene
glucosyl esters, was found in two other novel taxa of Heliobacteria, Heliorestis
acidaminivorans sp. nov. strain HR10BT, and Candidatus Heliomonas lunata strain
SLH [63]. An isolate from Lake Bogoria hot spring, obligate alkaliphile Paracoccus
bogoriensis BOG6T was found to secrete astaxanthin with yield of 0.4 mg/g of wet
cells indicating a potential for application in commercial production of carotenoids
[64]. A sulfur-oxidizing alkaliphilic heterotroph, Roseinatronobacter thiooxidans
ALG1, synthesized carotenoids in organic nitrogen-containing medium [62]. Cisand trans-canthaxanthin (cx) isomers with different antioxidant activities were
isolated from orange-pigmented mesophilic bacterium Dietzia sp. K44 with optimum growth at pH 8. It was suggested that 9-cis-cx is more effective as an
antioxidant than all-trans-cx [65].
Detailed pigment analysis of alkaliphilic purple sulfur bacterium Thiorhodospira
sibirica gen. nov. sp. nov from Siberian soda lakes revealed carotenoids of the
spirilloxanthin series with anhydrorhodovibrin (37.6%), followed in quantity by
rhodopsin (31.5%), spirilloxanthin (21.8%), didehydrorhodopin (6.5%), and lycopene (2.7%) [66]. Carotenoids of spirilloxanthin series are not uncommon among the
phototrophic purple sulfur bacteria. The spirilloxanthin was the main pigment in a
new bacterium from a soda lake in Mongolia Ectothiorhodosinus mongolicum gen.
nov., sp. nov. [67], in an alkaliphilic and halophilic Ectothiorhodospira variabilis
sp. nov. [68], in a new species of the genus Ectothiorhodospira, Ect. magna sp. nov.
The presence of carotenoids of the spirilloxanthin series was supported by the
maximum light absorption within a range of 485–514 nm and a shoulder at
545 nm. A similar in vivo pigment absorption spectrum with three longwave
maxima is typical of many Ectothiorhodospiraceae species [69]. Carotenoids of
Thioalkalicoccus limnaeus gen. nov., sp. nov., isolated from cyanobacterial mats of
soda lakes in certain ecoregions called steppe of the southeast Siberia, Russia,
demonstrated the spectral characteristics similar to 3,4,3H,4H tetrahydrospirilloxanthin [70]. The presence of both spheroidene and spirilloxanthin carotenoids was reported for Rubribacterium polymorphum gen. nov., sp. nov., an
alkaliphilic nonsulfur purple bacterium from an eastern Siberian soda lake [71, 72]
and for two nonsulfur purple alkaliphilic isolates of a new genus and species of the
family Rhodobacteraceae, Rhodobaculum claviforme gen. nov., sp. nov. [73]. Carotenoids of the spheroidene series were found in the cells of Roseibacula alcaliphilum
gen. nov. sp. nov. A new alkaliphilic aerobic anoxygenic phototrophic bacterium
from a meromictic soda lake Doroninskoe (East Siberia, Russia) contains bacteriochlorophyll α and carotenoids [74].
The fact that the pigments of a new facultative alkaliphile strain of the genus
Roseococcus, Rsc. suduntuyensis sp. nov. had different retention times in chromatography indicates that carotenoids differed from spirilloxanthin. In these carotenoids of the strain, the spirilloxanthin methoxy groups are replaced by glycosides.
Similar replacements were observed in the carotenoids of the type strain of Rsc.
Metabolites Produced by Alkaliphiles with Potential Biotechnological. . .
175
produced by alkaliphilic Microbacterium arborescens AGSB, obtained from coastal
sand dunes. Novel carotenoid glucoside esters have been reported from alkaliphilic
Heliobacteria [62]. Later, the same type of carotenoid, OH-diaponeurosporene
glucosyl esters, was found in two other novel taxa of Heliobacteria, Heliorestis
acidaminivorans sp. nov. strain HR10BT, and Candidatus Heliomonas lunata strain
SLH [63]. An isolate from Lake Bogoria hot spring, obligate alkaliphile Paracoccus
bogoriensis BOG6T was found to secrete astaxanthin with yield of 0.4 mg/g of wet
cells indicating a potential for application in commercial production of carotenoids
[64]. A sulfur-oxidizing alkaliphilic heterotroph, Roseinatronobacter thiooxidans
ALG1, synthesized carotenoids in organic nitrogen-containing medium [62]. Cisand trans-canthaxanthin (cx) isomers with different antioxidant activities were
isolated from orange-pigmented mesophilic bacterium Dietzia sp. K44 with optimum growth at pH 8. It was suggested that 9-cis-cx is more effective as an
antioxidant than all-trans-cx [65].
Detailed pigment analysis of alkaliphilic purple sulfur bacterium Thiorhodospira
sibirica gen. nov. sp. nov from Siberian soda lakes revealed carotenoids of the
spirilloxanthin series with anhydrorhodovibrin (37.6%), followed in quantity by
rhodopsin (31.5%), spirilloxanthin (21.8%), didehydrorhodopin (6.5%), and lycopene (2.7%) [66]. Carotenoids of spirilloxanthin series are not uncommon among the
phototrophic purple sulfur bacteria. The spirilloxanthin was the main pigment in a
new bacterium from a soda lake in Mongolia Ectothiorhodosinus mongolicum gen.
nov., sp. nov. [67], in an alkaliphilic and halophilic Ectothiorhodospira variabilis
sp. nov. [68], in a new species of the genus Ectothiorhodospira, Ect. magna sp. nov.
The presence of carotenoids of the spirilloxanthin series was supported by the
maximum light absorption within a range of 485–514 nm and a shoulder at
545 nm. A similar in vivo pigment absorption spectrum with three longwave
maxima is typical of many Ectothiorhodospiraceae species [69]. Carotenoids of
Thioalkalicoccus limnaeus gen. nov., sp. nov., isolated from cyanobacterial mats of
soda lakes in certain ecoregions called steppe of the southeast Siberia, Russia,
demonstrated the spectral characteristics similar to 3,4,3H,4H tetrahydrospirilloxanthin [70]. The presence of both spheroidene and spirilloxanthin carotenoids was reported for Rubribacterium polymorphum gen. nov., sp. nov., an
alkaliphilic nonsulfur purple bacterium from an eastern Siberian soda lake [71, 72]
and for two nonsulfur purple alkaliphilic isolates of a new genus and species of the
family Rhodobacteraceae, Rhodobaculum claviforme gen. nov., sp. nov. [73]. Carotenoids of the spheroidene series were found in the cells of Roseibacula alcaliphilum
gen. nov. sp. nov. A new alkaliphilic aerobic anoxygenic phototrophic bacterium
from a meromictic soda lake Doroninskoe (East Siberia, Russia) contains bacteriochlorophyll α and carotenoids [74].
The fact that the pigments of a new facultative alkaliphile strain of the genus
Roseococcus, Rsc. suduntuyensis sp. nov. had different retention times in chromatography indicates that carotenoids differed from spirilloxanthin. In these carotenoids of the strain, the spirilloxanthin methoxy groups are replaced by glycosides.
Similar replacements were observed in the carotenoids of the type strain of Rsc.
Metabolites Produced by Alkaliphiles with Potential Biotechnological. . .
175