Hygienic and microbiological influences exerted on natural water biotopes by algae and the growth of water plants. 1. Communication: antibacterial properties of three water algae (Hydrodictyon reticulatum, Chlorella vulgaris, Aphanothece nidulans) in vitro
Gräf, W.; Baier, W.
Zentralblatt für Bakteriologie Mikrobiologie und Hygiene. 1. Abt. Originale B Hygiene 174(5): 421-442
1981
ISSN/ISBN: 0932-6073 PMID: 6805159 Document Number: 181310
The growth-inhibiting behaviour of abacterial, liquid pure cultures made up of three water algae (Hydrodictyon reticulatum, Chlorella vulgaris, Aphanothece nidulans) which were made to grow profusely in special culture containers under constant exposure to light and ventilation was examined in ten different species of microorganisms during a period of contact of 4 days both in the light and in the dark. Subjected to the test were the 5 pathogenic species Staphylococcus aureus, Klebsiella aerogenes, Pseudomonas aeruginosa, Salmonella typhimurium and Candida albicans as well the 5 bacterial contamination indicators E. coli (faecal indicator), Streptococcus faecalis (enterococci), Enterobacter aerogenes ("coliforms"), Staphylococcus epidermidis (dermic germ) and Bacillus subtilis ("contamination germ"). It was found that --Hydrodictyon reticulatum and Aphanothece nidulans exert a strong antibacterial effect, while Chlorella vulgaris provides no indication of a bacterial growth-inhibiting effect. --this antibiosis is linked with the assimilative activity of the algal cultures, as in the dark no antibacterial action is discernible --the "antibiotic principle" must be liable to transitory or rapid disintegration because the algal cultures are ineffective in the dark and also culture filtrates of 5-days old algal cultures exercise no growth-inhibiting effect. With respect to the sanitation of waters it is important to state that a profuse growth of algae produces a certain, but hardly reliable "biological water disinfection" and renders difficult the assessment of the quality of a water-course as a result of the elimination of the usual contamination indicators. Therefore, additional microbiological quality parameters must be used for assessment of pollution of swimming pools with strong algal growth.