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4. Isolation of Carotenoid-producing Yeasts from an Alpine Glacier

Author

Amaretti, Alberto, Simone, Marta, Quartieri, Andrea, Masino, Francesca, Raimondi, Stefano, Leonardi, Alan, and Rossi, Maddalena

Subjects
Psychrophilic yeasts, lcsh:Computer engineering. Computer hardware, lcsh:TP155-156, HPLC-DAD analysis, lcsh:TK7885-7895, yeast, lcsh:Chemical engineering, Carotenoids, Carotenoids, yeast, HPLC-DAD analysis, Psychrophilic yeasts
Abstract

Cold-adapted yeasts are increasingly being isolated from glacial environments, including Arctic, Antarctic, and mountain glaciers. Psychrophilic yeast isolates mostly belong to Basidiomycota phylum, such as Cryptococcus, Mrakia, and Rhodotorula, and represent an understudied source of biodiversity for potential biotechnological applications. Since some basidiomycetous yeast genera (e.g. Rhodotorula, Phaffia, etc.) were demonstrated to produce commercially important carotenoids (e.g. ß-carotene, torulene, torularhodin and astaxanthin), the present study aimed to obtain psychrophilic yeast isolates from the surface ice of an Italian glacier to identify new pigment-producers. 23 yeast isolates were obtained. Among them, three isolates giving pigmented colonies were subjected to ITS1/ITS2 sequencing and were attributed to the Basidiomycetous yeasts Dioszegia sp., Rhodotorula mucilaginosa, and Rhodotorula laryngis. The strains were cultured batch-wise in a carbon-rich medium at 15°C until the stationary phase was reached, then the pigments were extracted from freeze-dried biomass using a DMSO:acetone mixture. Visible absorption spectrum and HPLC-DAD analysis revealed the presence of carotenoid pigments. In batch cultures of Dioszegia sp., carotenoid production was growth-associated and yielded up to 3.4 mg/L of a molecule exhibiting an m/z ratio (568) consistent with the molecular weight of xanthophylls bearing 2 OH groups.

Published
2014

6. Role of bifidobacteria in the hydrolysis of chlorogenic acid

Author

Regione Emilia Romagna, European Commission, Raimondi, Stefano, Anighoro, Andrew, Quartieri, Andrea, Amaretti, Alberto, Tomás Barberán, Francisco, Rastelli, Giulio, Rossi, Maddalena, Regione Emilia Romagna, European Commission, Raimondi, Stefano, Anighoro, Andrew, Quartieri, Andrea, Amaretti, Alberto, Tomás Barberán, Francisco, Rastelli, Giulio, and Rossi, Maddalena

Abstract

This study aimed to explore the capability of potentially probiotic bifidobacteria to hydrolyze chlorogenic acid into caffeic acid (CA), and to recognize the enzymes involved in this reaction. Bifidobacterium strains belonging to eight species occurring in the human gut were screened. The hydrolysis seemed peculiar of Bifidobacterium animalis, whereas the other species failed to release CA. Intracellular feruloyl esterase activity capable of hydrolyzing chlorogenic acid was detected only in B. animalis. In silico research among bifidobacteria esterases identified Balat_0669 as the cytosolic enzyme likely responsible of CA release in B. animalis. Comparative modeling of Balat_0669 and molecular docking studies support its role in chlorogenic acid hydrolysis. Expression, purification, and functional characterization of Balat_0669 in Escherichia coli were obtained as further validation. A possible role of B. animalis in the activation of hydroxycinnamic acids was demonstrated and new perspectives were opened in the development of new probiotics, specifically selected for the enhanced bioconversion of phytochemicals into bioactive compounds.

Published
2015

11. The Probiotic Bifidobacterium breve B632 Inhibited the Growth of Enterobacteriaceae within Colicky Infant Microbiota Cultures.

Author

Simone, Marta, Gozzoli, Caterina, Quartieri, Andrea, Mazzola, Giuseppe, Di Gioia, Diana, Amaretti, Alberto, Raimondi, Stefano, and Rossi, Maddalena

Abstract

Infant colic is a common gastrointestinal disorder of newborns, mostly related to imbalances in the composition of gut microbiota and particularly to the presence of gas-producing coliforms and to lower levels of Bifidobacteria and Lactobacilli. Probiotics could help to contain this disturbance, with formulations consisting of Lactobacillus strains being the most utilized. In this work, the probiotic strain Bifidobacterium breve B632 that was specifically selected for its ability to inhibit gas-producing coliforms, was challenged against the Enterobacteriaceae within continuous cultures of microbiota from a 2-month-old colicky infant. As confirmed by RAPD-PCR fingerprinting, B. breve B632 persisted in probiotic-supplemented microbiota cultures, accounting for the 64% of Bifidobacteria at the steady state. The probiotic succeeded in inhibiting coliforms, since FISH and qPCR revealed that the amount of Enterobacteriaceae after 18 h of cultivation was 0.42 and 0.44 magnitude orders lower (ρ < 0.05) in probioticsupplemented microbiota cultures than in the control ones. These results support the possibility to move to another level of study, that is, the administration of B. breve B632 to a cohort of colicky newborns, in order to observe the behavior of this strain in vivo and to validate its effect in colic treatment. [ABSTRACT FROM AUTHOR]

Published
2014
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