PRODUCTION AND PROPERTIES OF 2,3-BUTANEDIOL: XXXI. PILOT PLANT STUDIES ON THE FERMENTATION OF WHEAT BY AEROBACILLUS POLYMYXA

Abstract

In this paper are described the construction and operation of a pilot plant in which whole wheat mashes were successfully fermented by Aerobacillus polymyxa. A yield of 8.9 lb. of levo-2,3-butanedio1 and 5.9 lb. of ethanol per bushel of wheat was obtained, which is a fermentation efficiency of 90%. The best fermentations were obtained at 32 °C. using a 15% mash buffered with calcium carbonate. Agitation increased the fermentation efficiency at 96 hr. but decreased the diol-to-ethanol ratio. Reduced pressure did not change the efficiency but markedly reduced the ratio of diol to ethanol. Aeration had little effect. The presence of contamination organisms was highly detrimental and it was necessary to sterilize the mash, vessels, and piping. Although a backstocking technique could be practised in the preparation of inoculum, frequent recourse to stock cultures or improved strains was found advisable for maintenance of high yields.