Bacteriostatic effects of some algae- and lemna minor extracts

Abstract

1. In some stages of their development the algae Spirogyra sp. and Euglena viridis contain in their cells bacteriostatic substances that have a reducing influence upon the growth of Sphaerotilus natans, Bacillus mycoides and Leptothrix ochracea. The extract of these algae were found to have no bacteriostatic effect upon Escherichia coli, Sarcina lutea and Staphylococcus aureus. 2. In relation to all above mentioned bacteria species on Agar plates, during our testing the extracts from Cladosphora glomerata, Zygnema sp., Chlamydomonas sp., Stratonostoc gelatinosum, Anabaena sp., Oscillatoria sp., Aphanizomenon flos aquae and Microcystis sp., no bacteriostatic effects could ever be detected. 3. Extract from Lemna minor had bacteriostatic effect in relation to Sphaerotilus natans. 4. Bacteriostatic effect of algal cell \3- contents appeared in some unprecised stages of their growth in the pond \3- possibly in some connection with its properties. 5. In general, the activity of an extract from cell contents of the algae was quickly lost in indoor conditions. When the extract was preserved at −4°C its bacteriostatic activity, was often pronouncedly enhanced and in the case of Spirogyra also prolonged in time to as much as 6 months. 6. Extract from Euglena viridis maintained its activity when, pasteurized at 60\dgC, 70\dgC and 80\dgC. In this latter case the extract was sterile. 7. Bacteriostatic effect of Lemna minor extract disappeared in the refrigerator within 5 days. 8. Cell extract from Microcystis, obtained by refrigeration and defrosting (cell juice blue-violet in colour) which was poisonous to Daphnia longispina and Eucypris virens, did, not reduce the growth of bacteria on Agar plates.