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BACKGROUNDOver 90% of microalgae cultivations on a commercial scale are grown in outdoor systems, which means that the performance of these bioprocesses is dependent on the climatic conditions in each particular locality. Thus, the selection of suitable locations according to their climatic conditions is extremely important to develop technically and economically viable processes. This study aimed to assess the influence of geographic position and local climate on the microalgae culture performance in photobioreactors, as a strategy to map potential regions for commercial‐scale microalgae production. Six extreme positions of Brazil were chosen to represent their respective climates in the four seasons of the year.RESULTSThe climatic variables considered were temperature, light irradiance, and photoperiod. In terms of both biomass and lipid production in an annual overview, the results showed that tropical climates and low latitudes favor the microalgae culture. The highest annual average biomass productivity (0.278 g L−1 d−1) and annual average lipid productivity (0.056 g L−1 d−1) were recorded in Boa Vista‐RR (02° 49′ 12″ N), in summer.CONCLUSIONThe geographic position and the local climate are decisive criteria in the performance of these processes, being able to increase up to three and four times the biomass productivity and lipid productivity, respectively. © 2020 Society of Chemical Industry

The aim of this work was evaluate the role of photoperiods (long-term, frequencies and short) on the growth and lipid content of microalgae Scenedesmus obliquus CPCC05. The results showed that Scenedesmus obliquus can store sufficient energy to sustain cell growth for continuous periods of up to 2h in the dark, without affecting the photosynthetic rate. The values for maximum biomass (9.58mg/Lh) and lipid productivities (2.56mg/Lh) were obtained at photoperiod of 0.91:0.09s (light:dark) and 48 t/d, respectively. Moreover, the best trade-offs between biomass productivity and light energy economy occurred in photoperiods of 0.5:0.5s and 0.91:0.09s (light:dark), and those between lipid productivity and light energy economy occurred in the frequency photoperiod of 24 and 48 t/d. Thus, the use of the photoperiods are an effective strategy for reducing costs of microalgal biomass production.

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This work is focused on the optimization of the ultrasound-assisted extraction of antioxidant compounds with photoprotective effect from palm pressed fiber. The influence of ultrasound intensity and pulse cycle was investigated by means of a central composite rotational design. The optimized condition was ultrasound intensity of 120W.cm and pulse factor of 0.4, yielding 3.24wt%. Compounds such as fatty acids, β-sitosterol, α-tocopherol, squalene, total phenolics and carotene were identified. The extract presented antioxidant activity towards synthetic (2,2-diphenyl-1-picrylhydrazyl - DPPH, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) - ABTS) and biological radicals (Hydroxyl - OH), besides a sun protection factor of 15.01. Polar extracts from palm pressed fiber are promising candidates for use in cosmetic and pharmaceutical formulation since they present high antioxidant activity towards different radicals, combined with the high sun protection factor.

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