ABSTRACT
Biodiesel is an alternative fuel to addressing the energy shortage problem. Microbial lipids have attracted widespread attention as one of the potential feed-stocks for cost-effective and efficient biodiesel production. However, the large-scale production of microbial lipids is hampered by the complexity and the high cost of aseptic culturing approach. Metschnikowia pulcherrima is an oleaginous yeast with strong environmental adaptability. It is capable of utilizing a wide spectrum of substrates, and can be cultured under non-sterile conditions. Therefore, this yeast has great potential to replace the traditional oleaginous microorganisms, particularly in the area of recycling wastewater and solid waste for the production of biodiesel. Based on the analysis of lipid production and application conditions of M. pulcherrima, this review summarized the unique advantages of M. pulcherrima and the key factors affecting lipids production. We further discussed the feasibility of cultivating M. pulcherrima on various organic wastes under non-sterile conditions for lipids production. Moreover, we analyzed the challenges associated with M. pulcherrima's in the yield and mechanism for lipids production, and proposed perspectives for how to achieve efficient biodiesel production using this yeast.
Subject(s)
Biofuels , Candida , Lipids , Metschnikowia , YeastsABSTRACT
ABSTRACT: The sensory quality of wines is affected by the compounds produced by the action of the yeasts used in alcoholic fermentation. This work aimed at assessing the physicochemical, aromatic and sensory properties of the 'Riesling Italico' white wines produced by using the Saccharomyces and non-Saccharomyces yeasts. The yeasts S. cerevisiae, S. cerevisiae cerevisiae, S. bayanus, Torulaspora delbrueckii and Metschnikowia pulcherrima were inoculated individually into the must. For 10 days, the alcohol was left to ferment in 7 L carboys in triplicate, at 15º C temperature. The standard physicochemical analyses were done and the quality of the wines was determined. The volatile compounds were identified and quantitative descriptive sensory analyses were performed. All the yeasts produced wines with the characteristic alcohol, volatile acidity and residual sugar content as stipulated by the Brazilian legislation. The T. delbrueckii yeast produced high-content phenylethyl acetate, isoamyl acetate and ethyl decanoate wines, of superior olfactory quality and sensory rating.
RESUMO: Durante a fermentação alcoólica as leveduras produzem compostos que influenciam a qualidade sensorial dos vinhos. O objetivo do trabalho foi avaliar as propriedades físico-químicas, aromáticas e sensoriais do vinho branco da variedade Riesling Italico elaborado a partir de leveduras Saccharomyces e "não-Saccharomyces". Foram inoculadas separadamente no mosto as leveduras S. cerevisiae, S. cerevisiae cerevisiae, S. bayanus, Torulaspora delbrueckii e Metschnikowia pulcherrima. A fermentação alcoólica ocorreu em garrafões com 7 L de mosto, em triplicata, por 10 dias a 15 ºC. Foram realizadas análises físico-químicas padrão e de identificação da qualidade dos vinhos, além das análises de compostos voláteis e sensorial descritiva quantitativa. Todas as leveduras produziram vinhos com teores de álcool, acidez volátil e açúcar residual de acordo com a legislação. A levedura T. delbrueckii produz vinhos com concentrações elevadas de acetato de feniletila, acetato de isoamila e decanoato de etila, resultando em boa qualidade olfativa e avaliação sensorial.