Adaptation and growth of Chlorella vulgaris on vinasses from industrial alcoholic fermentation to obtain lipids for biofuel production
Alcoholic distillation from sugarcane generates highly polluting wastes such as vinasses. Last year, ethanol production in Colombia from sugarcane crops was 4, 4 x109L. Moreover, for every liter of ethanol produced, between 7 to 14 liters of vinasse are generated, producing an enormous contamination for its large carbon, nitrogen, and phosphorus contents. In addition, between 5 to 10 percent of these wastes can be used in reprocessing and fertigation processes on soils. Therefore, it is a huge contamination problem. Microalgae are a wide group single-celled organisms. The microalgae might growth in different forms such as autotrophic, heterotrophic, and mixotrophic. These microorganisms present a high adaptation capability in almost all environments. Heterotrophic growth of C. vulgaris is the culture method more used for its industrial production since high lipid contents are obtained.In consequence, the aim of this study was to adapt and evaluate the heterotrophic growth of Chlorella vulgaris in a medium composed by vinasses from industrial distilleries. 30%, 60%, and 80% of vinasses concentrations (VC) were evaluated as the culturing media for microalgal growth to obtain high lipid contents for biofuel production.
- vulgaris was grown at 30%, 60% and 80% VC in a formulated medium. The best biomass production (15 g/L) was obtained at 144h cultivation in 60% VC. Protein/lipid concentrations when C. vulgaris was grown in 30, 60, and 80 percent VC were 40/22; 30/26 and 20/30 (%) respectively. Although 80% VC showed a higher lipid content compared to 60% VC, less biomass production was obtained (4 g/L). Even though in 60% CV the lipid content is lower than in 80% VC, the increase in biomass production could account for a more total lipid production yields.
In conclusion, biomass and lipids productions are enhanced by heterotrophic growth conditions using vinasses as the culturing medium. The lipids content of the produced microalgae cake could be used for the production of biodiesel in an economic manner since vinasses are wastes generated in alcoholic fermentation processes at industrial scales.
Education: microbiologist, PhD in Cell, tumour and molecular biology from the Karolinska Institutet, Stockholm-Sweden (alumni 2004). Currently, professor of microbiology and biochemistry at the Chemical Engineering Department in Universidad Nacional de Colombia.
Area: biotechnology, microbiology.