Heterotrophic cultivation of Euglena gracilis on chemically pretreated media

Abstract In this research, the impact of chemical agents on the growth of Euglena gracilis and contaminants (S. cerevisiae and B. subtilis) in different cultivation media was studied. E. gracilis was cultivated on modified Hutner and complex medium in Erlenmeyer flasks and a stirred tank bioreactor. H2O2 and antimycin were used as suppressors of contaminant growth activities during algae cultivation. The use of antimycin as a chemical suppressor of contaminants is not recommendable because of its significant impact on the E. gracilis growth. At a H2O2 concentration of 5 mg L-1 contaminant growth activities were almost completely suppressed. In these conditions, E. gracilis is capable to grow, but a further increase of H2O2 concentration is related to significant reduction of algae growth. H2O2 as a suppressor of contaminants has great potential for industrial application, but its optimal concentration for a particular bioprocess has to be determined in order to obtain the maximal bioprocess efficiency.