Resumo

According to the revision of the UN population prospects , the world population is projected to grow by 34 percent in 2050. This population increase will bring some issues, which need to be solved, like: greenhouse gases (GHG) concentration increases; energy and food demand; arable land usage; maintenance of natural resources; and management of wastes. The search for sustainability has been incessant, alternative energy sources, greater availability of area to food production, and productivity and yield increase have been the goal worldwide. In this sense, great interest has been given to the biotechnological potential of microalgae. As a source for energy and special compounds (metabolic products; functional foods), microalgae are photosynthetic microorganisms that have the capacity to grow mixotrophically in wastewaters and media containing organic and inorganic compounds. From this possibility, the present work is aimed to study the development of Scenedesmus bijuga in media prepared from soft drinks. Soft drink industry generates a heterogeneous mixture of chemicals and wastes that includes sugar and artificial sweeteners. Those that cannot be easily treated or discharged in natural resources, we propose to use for microalgae cultivation. Allying both industries it would be possible to reduce the microalgae cultivation costs and transform a waste stream to a profitable material. The microalgae growth rates in soft drink, the influences of the dark color from cola soft drinks and the aspartame from the diet soft drinks were studied. Microalgae were cultivated on 4 different treatments (media composition): 100% of diet cola (DC-100); 100% of diet soda (DS-100); 10% of regular cola (RC-10); and 10% of regular soda (RS-10). The results obtained were satisfactory: the treatment with the lowest growth (DC-100) had productivity about 5% higher than that obtained from the cultivation in standard medium (BG11). All others presented superior results, with the highest growth observed in RC-10.