Production of biomass by Spirulina maxima using sugar beet vinasse in growth media

Cultivation of Spirulina maxima in media containing vinasse from beet molasses fermentation has been studied in both batch cultures and a photobioreactor. The results obtained in batch tests showed that S. maxima was able to grow in Schlosser media containing up to 5 g/L of vinasse or alkaline diluted vinasse (5 g/L). Biomass concentrations ranging from 3.5 and 4.8 g/L, productivities from 0.15 to 0.24 (g/L d) and specific growth rates about 0.1 d −1 were found. Betaine, an organic nitrogenous compound present in vinasse, was completely consumed. The continuous operation in a tubular photobioreactor with Schlosser medium supplemented with 2 g/L of vinasse led to S. maxima concentrations about 8 g/L and productivities of 0.7 g/L d for an hydraulic retention time of 11 d using a light intensity of 3000 lux, slightly higher than those achieved with Schlosser medium, showing that the addition of vinasse presents a positive effect on the growth of the microalgae.