B. Siegmund & E. Leitner (Eds): Flavour Sci., 2018, Verlag der Technischen Universität Graz DOI: 10.3217/978-3-85125-593-5-17, CC BY-NC-ND 4.0 87 Flavour generation from microalgae in mixotrophic cultivation ANDRIÉLI BORGES SANTOS 1 , Karem Rodrigues Vieira 1 , Pricila Nass Pinheiro 1 , Bruno Nicolau Paulino 2 , Juliano Lemos Bicas 2 , Eduardo Jacob-Lopes 1 and Leila Queiroz Zepka 1 1 Federal University of Santa Maria, Department of Technology and Food Science. Santa Maria, Brazil 2 Campinas State University, Faculty of food engineering, Department of Food Science. Campinas, Brazil Abstract Microalgae are known to produce several volatile organic compounds that can be obtained from the biomass or released extracellularly into the medium. The aim of this study was to evaluate the generation of volatile organic compounds with flavour potential from the microalga Phormidium autumnale in mixotrophic cultivation. The experiment was conducted in a New Brunswick Scientific BioFlo ® 310 bioreactor operating under a batch system, with a 1.5 L working volume. The experimental conditions were as follows: initial inoculum concentration 100 mg L -1 , temperature 25°C, pH adjusted to 7.6 and aeration of 1.0 volume air per culture volume per minute, supplemented with 5 g.L -1 of sucrose and constant light intensity of 4 klux. The volatile compounds were isolated by solid phase micro-extraction applied in headspace of residence time (144 hours), separated by gas chromatography and identified by mass spectrometry (HS-SPME- GC/MS), co-injection of standards and Kovats index. The major products in the bioreactor were 2,4-decadienal (46.03%), 3-methyl-1-butanol (12.39%), hexanol (4.17%) and 2-ethyl-1-hexanol (3,51%). The descriptor flavour of the compounds detected in experiments was mainly classified as fried food, fruity, spice, and floral compounds. In conclusion, the results have shown that the mixotrophic cultivation of the Phormidium autumnale could be a potential biotechnological to produce natural flavours. Introduction Microalgae are a group of photosynthetic microorganisms typically unicellular and eukaryotic. Although cyanobacteria belong to the domain of bacteria, and are photosynthetic prokaryotes, they are often considered microalgae [1]. Microalgae and cyanobacteria are considered some of the most promising feedstocks for the supply of food and nonfood industries [2; 3]. Because they present a high content of macronutrients (proteins, carbohydrates, and lipids), microalgae have the potential to enhance the nutritional value of foods [4]. They may also be used as a feed source for many aquatic organisms and livestock [5]. Microalgae-based systems for chemicals production are an emergent area, representing a great promise for industrial application. The growing interest in natural products guides the development of the technologies that employ microorganisms, including microalgae, which are able to synthesize specific volatile organic compounds. Therefore, the selection of a mode of cultivation of microalgae is of vital importance. Four major modes of microalgae cultivation can be adopted, namely photo-autotrophic, heterotrophic, photo-heterotrophic, and mixotrophic [6]. Mixotrophic microalgae use different energy and carbon sources so that they may use organic or inorganic sources and light in different combinations. Mixotrophy makes microalgae more flexible because it may gather both the carbon and energy demand from organic or inorganic sources and light simultaneously [7].