A small "side experiment":

For more than 800 years, people have used the property of hops to preserve food - the most common example is beer. Hop extracts are used in the sugar industry to fight thermophile bacteria as they would multiply too much during extraction processes. Formalin was also in use, before its toxicity was proved. Hop extracts are entirely harmless for the human body. We found out that the Zuckerforschung Tulln GmbH (ZFT) was looking for new applications for hops. We had the idea to try using hops extracts to restrain the growth of the blue-green algae. Such a property might have been of great use when preventing the growth of algae in natural swimming ponds. We contacted Florian Emerstorfer, an employee of the ZFT and asked, if we could start a test series with our "best" strains of Cyanobacteria and hops extracts. After consulting him we started two cultures and one control culture with a concentration of 200 and 2000ppm of hop extract. With this test series we measured the growth of all

the Cyanobacteria cultures regularly. However, we had to find out that, no matter how hight the concentration, the hop extract did not have any influence on the growth of the algae. Hop extract can therefore not be used to rehabilitate ponds with a strong growth of algae. Even though we could not obtain the desired results, we were glad to have found some insight into the properties of hops.