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.摘要 本研究考察了化学试剂对不同培养基中纤细裸藻（Euglena gracilis）及污染物酿酒酵母（S. cerevisiae）、枯草芽孢杆菌（B. subtilis）生长的影响。研究采用改良赫特纳培养基与复合培养基，在锥形瓶及搅拌罐式生物反应器中培养纤细裸藻。过氧化氢（H₂O₂）与抗霉素被用作藻类培养过程中污染物生长的抑制剂。鉴于抗霉素对纤细裸藻的生长具有显著抑制作用，因此不推荐将其作为污染物的化学抑制剂。当过氧化氢浓度为5 mg·L⁻¹时，污染物的生长活动几乎被完全抑制；在此条件下纤细裸藻仍可正常生长，但进一步提高过氧化氢浓度会显著抑制藻类生长。过氧化氢作为污染物抑制剂具备良好的工业应用潜力，但为获得最优的生物过程效率，需针对特定生物工艺确定其最佳使用浓度。