CONICET | Buscador de Institutos y Recursos Humanos

In this work the growth of Spirulina platensis in a residual effluent from the wort production for brewing were evaluated. Then, from the best growth condition, microalgae biochemical composition was determined.100 mL shake-flasks were used. Brewery wastes were subjected to centrifugation prior to dilution with sterilized water, Zarrouk medium, or a mix of sterilized water and Zarrouk in order to achieve chemical oxygen demand (COD) values of approximately 400, 1300 and 4000 mg O2/L, from an initial COD value of 40000 mg O2/L. Control cultures were realized using Zarrouk. Microalgae growth (dry weight basis, DW), protein, total carbohydrates, lipid content and pigments (phycocyanin, chlorophyll and carotenoids) were determined.When brewery wastes were diluted with sterilized water, S. platensis was able to grow under a COD value of 400 mg O2/L up to 7 days of culture. After that, growth was limited at the same way as the other culture conditions, compared to control which grew about 5-fold increase at 14 days of culture. Additionally, both 400 and 1300 mg O2/L COD values were able to promote a growth similar to that registered in control cultures when wastes were diluted with a mix of sterilized water and Zarrouk at 14 days of culture. However, growth was limited under a COD value of 4000 mg O2/L. Similar behaviour was observed when wastes were diluted only with Zarrouk medium.According to obtained results, the most suitable and economic diluent solution was a mix of sterilized water and Zarrouk. Although lipid content and total carbohydrates resulted 67% and 64% higher than the control, respectively, microalgae growth and pigments production were limited using that mix and a COD value of 4000 mg O2/L. Therefore, COD values of 400 and 1300 mg O2/L resulted the most appropriated for S. platensis growth without modify biochemical composition.