鹹水

In Japan proper where the climate is unfavorable to the production of salt from sea water by solar evaporation, salt field process only is utilized its manufacture. As the brine obtained by this process contains coinparatively large quantities of sulphates and other ingredients, it is unavoidable that they should cause much trouble in the production of pure salt. While both physical and chemical methods are in use for the purification of the brine, we have never been .informed of the application of any biological process to it. The wr i t er has made an investigation as to the possibility of isolating any halophilic bacteria which have a strong reducing power on the troublsome sulphates in the brine. In the first experiment, using van Delden's medium, the writer obtained a species of bacteria, from some waters and soils in the farm of the department of agriculture, which resembles Spirillum desulfuricans Beijerinck. However the bacteria isolated were excluded from the scope of the investigation because they could not be developed in a medium containing over one percent. of sodium chloride. Next, the writer confir med the presence of the desired halophilic bacteria not only in every sample of solar salt from Taiwan, Tsingtau in China but also in a sample of Japanese brine from Funabashi. The durability of these bacteria in salt solution is so great that it can certainly develop in van Delden's medium, which contains twenty five percent. of sodium chloride, tinder anaerobic conditions. Moreover the halophilic bacteria along with the development in the medium, produce sulphuretted hydrogen gas vigorously. The successful development of these bacteria can be accomplished in van Delden's medium which is kept in anaerobic condition owing to the addition of Cystein hydrochloride. From the industr i a l standpoint, the author has attempted the application of these interesting bacteria to the purification of the brine. The seed culture of these bacteria were inoculated in the brine, which was maintained in anaerobic condition by passing the proper quanti ties of sulphuretted hydrogen through it. It was found that one third of the total quantities of the sulphates in the brine was reduced by these bacteria after two weeks at a temperature of 30℃.