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Title
Transformation of polyphenols from biomass by some yeast species
Authors
Anca-Roxana Hainal Ioana Ignat Irina Volf and Valentin I. Popa
Received
October 20, 2010
Published
Volume 45 Issue 3-4 March-April
Keywords
spruce bark, Asclepias syriaca, red grape seeds, aqueous extracts, polyphenolic compounds,
Abstract
Concerns on the complex processing of biomass have increased lately, being mainly aimed at fractional separation of all compounds, based on biorefinery principles. This technique allows the isolation and complete recovery of both primary and secondary components, using various chemical or biochemical agents. The application of an aqueous extraction procedure leads to the recovery of various types of extracts from the vegetable biomass, which could have either inhibitory or stimulating effects on the growth of microorganisms. From this point of view, studies were carried out on the influence of the aqueous extracts containing aromatic compounds with polyphenolic structure, separated from spruce bark, Asclepias syriaca plant and red grape seeds, on the development of yeast species which biosynthesize carotenoid pigments. Thus, two strains of yeast belonging to the Rhodotorula genus were cultivated on media containing the above-mentioned extracts. The obtained results have shown a different behavior of the two strains, which may be explained by their characteristic features, but also by the composition and concentration of polyphenols specific to the biomass source used for extraction. It was also found out that the yeasts used the polyphenolic compounds as a carbon and energy source, their concentration being reduced when increasing the duration of cultivation. The metabolism of polyphenols can be correlated with the carotenoid pigment content and composition.
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