ACETOBACTERINFECTION: PART IV. STRAINS OFACETOBACTER SUBOXYDANS, ISOLATED, RESPECTIVELY, FROM PITCHING YEAST AND FROM BEER

In 1924 Kluyvor and de Leeuw1 isolated from a Dutch beer an Acetobacter species which, as was shown by Visser't Hooft,2 brought about incomplete oxidation of many alcohols, sugars and related compounds. Because of this behaviour the new bacterium was given the name Acetobacter suboxydans. Several strains differing in some minor respects from the original culture have been recognized, and have proved to be useful agents for effecting certain oxidations in organic chemistry. The purpose of this communication is to record particulars of two strains of this species, which were isolated, respectively, from the pitching yeast of a brewery in Scotland and from the draught ale of a brewery in England. A. suboxydans has not been detected previously in British top-fermentation ales and beers. The species is not to be classed as a serious contaminant of beer but, nevertheless, it can produce much acid if allowed sufficient oxygen; hence, in the presence of air it can spoil beer within a short space of time.