Resumen Los compuestos aromáticos tienen amplias aplicaciones en las industrias alimentaria, cosmética y farmacéutica. Sin embargo, estos compuestos se producen principalmente por síntesis química. Una alternativa, sostenible y prometedora para la producción natural de compuestos aromáticos son los procesos fermentativos usando microrganismos. En este trabajo se obtuvo la producción de diferentes compuestos aromáticos en concentraciones significativas, como acetato de isoamilo, alcohol isoamílico, acetato de etilo y acetaldehído, entre otros, a partir de subproductos de la agroindustria (melaza de caña de azúcar), usando Pichia fermentans como inoculo. Los compuestos aromáticos se concentraron posteriormente por pervaporación y microencapsulación mediante secado por aspersión utilizando diferentes agentes encapsulantes. Se encontró que cuando estas técnicas se aplicaron a dos bebidas, produjeron un olor de notas afrutadas, especialmente las de plátano. Además, los panelistas identificaron notas amaderadas y alcohólicas. Finalmente, se encontró que los mejores agentes encapsulantes eran la dextrina (73,49 ppm) y la mezcla de dextrina y maltodextrina (72,58 ppm).

Abstract Aroma and fragrance compounds have broad applications in the food, cosmetic and pharmaceutical industries. However, these compounds are mainly produced by chemical synthesis. An alternative, sustainable and promising route for the natural production of flavour compounds is microbial transformation processes. In this work, we obtained the production of different aroma compounds in significant concentrations, such as isoamyl acetate, isoamyl alcohol, ethyl acetate and acetaldehyde, among others, from agribusiness by-products (sugarcane molasses) and using Pichia fermentans. These were subsequently concentrated by pervaporation and microencapsulation by spray drying using different encapsulating agents. The results showed that when these techniques were applied to two iced beverages, they produced an odour of fruity notes, especially those of banana. In addition, woody and alcoholic notes were identified by the panellists. Finally, the best encapsulating agents were dextrin (73.49 ppm) and the dextrin and maltodextrin mixture (72.58 ppm).

Abstract We present an improved method of direct transesterification suitable for the quantitative analysis of multiple dry samples for its fatty acid content, using a minimal amount of biomass and reactants. The method features an acid-catalyzed direct alcoholysis of microgram samples of dry biomass; the rationale behind the solvent and reagent proportions chosen is discussed. The method was validated using seven microbial strains with diverse lipid content (Saccharomyces cerevisiae, Saccharomyces boulardii, Candida tropicalis, Haematococcus pluvialis, Chlorella vulgaris, Spirulina platensis and Schizochytrium limacinum), and compared with a macroscale direct transesterification method, and with gravimetric analysis of lipids extracted with solvents. The microscale method showed a conversion of 98.06 ± 0.87% of the lipids, using approximately 3 mg of dry biomass, 1mL of 0.2M H2SO4 dissolved in anhydrous ethanol (the acid is the catalyzer and ethanol the reactant)). The mixture was maintained at 70 °C for 20 h with periodic mixing, and then extracted with 2mL n-heptane and analyzed by GC-FID. The lipid content was then calculated considering dilution and sample mass. This method is effective, reliable, and technically attractive for analytical and comparative purposes.

The objective of the present work was to isolate and select strains with potential to perform the biotransformation of terpenic substrates. Microorganisms obtained from a collection culture and also isolated from a natural source of terpene substrate were tested. Seventeen strains were selected by their resistance to terpenes in potato dextrose agar containing up to 1% of limonene or α-pinene and β-pinene (1:1). Subsequently, 10 strains were selected by their capacity of using these terpenes as sole carbon source in a mineral medium. The biotransformation capacity of these strains was tested and the products obtained were identified by GC-MS.

Estudos foram conduzidos para avaliar a produção de esporos de Bacillus atrophaeus, em escala laboratorial, por fermentação em estado sólido (FES) em biorreatores de coluna (aeração forçada), sacos plásticos e frascos tipo Erlenmeyer (aeração por difusão), usando bagaço de cana como suporte e melaço de soja como substrato. Diferentes teores de umidade (84%, 86% e 88%, 89%, 91% e 93%) e taxas de aeração (30mL/min, 45mL/min, 60mL/min e 90mL/min) foram estudados. A melhor condição para a produção de esporos no biorreator de coluna (3.3 x 10(10) CFU.g-1 matéria seca) foi 80% de umidade inicial, sem aeração. Em frascos Erlenmeyer e sacos de plástico a melhor esporulação foi na faixa de 1.7 a 4.7 x 10(10) CFU.g-1 matéria seca, com 88-93% de umidade inicial. A taxa de aeração não teve efeito significativo sobre o rendimento da esporulação. A umidade inicial apresentou efeito significativo relacionado ao tipo do biorreator. O estudo da cinética da esporulação demonstrou a possibilidade de reduzir o tempo de incubação para esporulação em dois dias.

Studies were conducted to evaluate Bacillus atrophaeus spores' production by solid-state fermentation (SSF) using sugarcane bagasse as support and soybean molasses as substrate at lab-scale in column bioreactors (forced aeration), plastic bags and Erlenmeyer flasks (aeration by diffusion). Different moisture contents (84%, 86% and 88%; 89%, 91% and 93%) and aeration rates (30mL/min, 45mL/min, 60mL/min and 90mL/min) were studied. The best condition for spore production (3.3x10(10) CFU.g-¹dry matter) in column bioreactor was 80% of initial humidity and no aeration. In Erlenmeyer flasks and plastic bags the best sporulation production reached 1.7 up to 4.7x10(10) CFU.g-1dry matter with 88-93% of initial moisture. The aeration rate had no significant effect on the spore yield. The initial moisture had a significant effect depending on the bioreactor type. Sporulation kinetic's assay was carried out and it showed the possibility to reduce the time of spore formation in two days.

Neste trabalho duas diferentes cepas de Ceratocystis fimbriata foram testadas para a produção de aromas frutais em fermentação no estado sólido (FES) utilizando como substratos casca e polpa de café, suplementados com glicose. Os experimentos foram realizados em frascos Erlenmeyer de 250 mL. As condições experimentais foram: umidade inicial de 70%, adição de 20% de glicose e pH 6,0. Os frascos foram cobertos com gaze e a aeração ocorreu por difusão passiva. A análise do "headspace"da cultura foi feita por cromatografia gasosa e 12 compostos foram detectados utilizando a casca de café. A análise respirométrica foi realizada para o acompanhamento do crescimento do microrganismo pela determinação do dióxido de carbono produzido. A produção de ésteres caracterizou o aroma frutal da cultura. A concentração máxima de voláteis totais foi alcançada após 72 h de cultivo em casca de café (28 µmol.L-1.g-1). Os principais compostos produzidos foram acetato de etila, etanol e acetaldeído, representando 84,7%, 7,6% and 2,0% dos voláteis totais, respectivamente.

The ability of two different strains of Ceratocystis fimbriata for fruity aroma production by solid state fermentation (SSF) was tested on coffee pulp and coffee husk complemented with glucose as substrates. Experiments were carried out in 250 mL Erlenmeyer flasks and the experimental conditions were: 70% of initial moisture, 20% of glucose addition and pH 6.0. Aeration was made by passive diffusion through the gauze covering the flasks. Headspace analysis of the culture by gas chromatography (GC) showed that 12 compounds were produced with coffee husk. Maximum total volatiles (TV) concentration was reached after 72 h of culture with coffee husk as substrate (28 µmol.L-1.g-1). Ethyl acetate, ethanol and acetaldehyde were the major compounds produced, representing 84.7%, 7.6% and 2.0% of TV, respectively. A pre-treatment with heat (100ºC/ 40 min) of substrates did not improve TV production. Respirometry analysis was used to determine the growth of the culture by measuring carbon dioxide produced. Results showed that the CO2 production follows the aroma production. This result shows the great potential for the use coffee pulp and coffee husk as substrates to microbial aroma production by solid state fermentation.