Obtenção e propriedades de toruleno da levedura Rhodotorula glutinis / Obtaining and properties of torulene from Rhodotorula glutinis yeast
AUTOR(ES)
Michelle Andriati Sentanin
FONTE
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia
DATA DE PUBLICAÇÃO
18/11/2011
RESUMO
Carotenoids are natural colorants, some of which are precursors of vitamin A. Since the past decade, an important role in reducing the risk of various degenerative diseases was attributed to these compounds. With these vital functions, the search for sources has intensified worldwide. The biotechnological production of specific carotenoids, using bacteria, fungi and yeasts, have attracted increasing interest. This study had the objective of optimizing the extraction of carotenoids from Rhodotorula glutinis, stimulating the production of carotenoids with mevalonic acid, substituting the medium with low-cost substrate and evaluating the stability and degradation of torulene. Chapter 1 presents a review of the biosynthesis of carotenoids and biotechnological production of these pigments in the last ten years, highlighting the production by bacteria, algae and fungi. The second chapter aims to optimize the extraction of carotenoids from the yeast Rhodotorula glutinis and assessing the effect of different concentrations of mevalonic acid on the production of carotenoids. Being a key precursor in the biosynthetic pathway of carotenoids in yeasts, it significantly influenced the production of pigments. Although the amount of biomass was not affected, the production of total carotenoid increased by 114% and the yield of torulene and ?-carotene increased by 157% and 168%, respectively. Chapter 3 is intended to lower the cost of production of carotenoids by the yeast under investigation, by replacing the usual culture medium YM with a sub-product of the cassava industry, the nutrient-rich substrate manipueira. To optimize the production of pigments, a full factorial design was used with four variables: pH, temperature, agitation and inoculum volume. The condition that favored yield of carotenoids was: 26°C, 250 rpm agitation, pH 7.0 and 10% volume of inoculum. In this condition, the production of carotenoids was 2068 mg/L of culture medium. The traditional YM provided the production of only 899 mg/L of culture medium of carotenoids. The fourth chapter aims to evaluate the stability of torulene produced by Rhodotorula, compared with well-known carotenoids, lycopene and b-carotene. For this purpose, model systems of low moisture were mounted, using microcrystalline cellulose as the matrix, which were kept in the dark or exposed to light for 15 days. The carotenoid that suffered the most degradation was lycopene, followed by b-carotene and torulene. Chapter 5 investigates the oxidative degradation of torulene and the volatile compounds produced during this process. To achieve this goal, model systems of low moisture were mounted, with microcrystalline cellulose matrix, in glass bottle, with injection of oxygen flow. Several degradation compounds were formed, of which the following compounds stood out quantitatively: methacrolein, prenal, 2,6-dimethyl-hepta-2,4-diene, 6-methyl-hept-5-en-2- one, 2-ethylhexanol, 2-ethenyl-1,3,3-trimethyl-cyclohexene and 3,3-dimethylciclohexilideno acetaldehyde
ASSUNTO(S)
carotenóides rhodotorula glutinis toruleno - degradação Ácido mevalônico torulene mevalonic acid
