Identification and analysis of metabolite production with biotechnological potential in Xanthophyllomyces dendrorhous isolates

Abstract

Antarctic microorganisms have developed different strategies to live in their environments, including modifications to their membrane components to regulate fluidity and the production of photoprotective metabolites such as carotenoids. Three yeast colonies (ANCH01, ANCH06 and ANCH08) were isolated from soil samples collected at King George Island, which according to their rDNA sequence analyses, were determined to be Xanthophyllomyces dendrorhous. This yeast is of biotechnological interest, because it can synthesize astaxanthin as its main carotenoid, which is a powerful antioxidant pigment used in aquaculture. Then, the aim of this work was to characterize the ANCH isolates at their molecular and phenotypic level. The isolates did not display any differences in their rDNA and COX1 gene nucleotide sequences. However, ANCH01 produces approximately sixfold more astaxanthin than other wild type strains. Moreover, even though ANCH06 and ANCH08 produce astaxanthin, their main carotenoid was β-carotene. In contrast to other X. dendrorhous strains, the ANCH isolates did not produce mycosporines. Finally, the ANCH isolates had a higher proportion of polyunsaturated fatty acids than other wild type strains. In conclusion, the reported X. dendrorhous isolates are phenotypically different from other wild type strains, including characteristics that could make them more resistant and better able to inhabit their original habitat, which may also have biotechnological potential.

Fig. 1

Phenotype and survival after UV-B irradiation of X. dendrorhous strains and King George Island isolates. The color phenotypes and survival percentages after exposure to UV-B (310 nm) radiation of ANCH01, ANCH06 and ANCH08 were compared to AVHN2 and UCD 67-385 wild type strains. a Strains cultivated on YM-agar plates for 4 days at 22 °C. b Survival percentage following of 73,062 mJ cm⁻² UV-B dose (3 h of exposure) (average of three independent cultures). c Holobasidium with terminal basidiospores of ANCH08, after 4 days of culture at 22 °C and then 23 days at 10 °C on DWR medium