I-IA_gDE~ and WALPOLE (1906)
first reported the production of 2,3 butanediol by Aerobacter aerogenes. It has since been shown that Bacillus polymyxa (DoN~E~ 1926), Aerobacter cloacae (THoMPso~ 1912), Aerobacter indologenes (MIcKELSO~ and WERK~A~ 1938), Pseudomonas hydrophila (STANIEg and ADAMS 1944), Serratia plymuthicum (PEDE~SON and B~EED 1928) and Bacillus subtilis (NEIsK 1945) ferment carbohydrate to produce 2,3 butanediol as a major metabolic product. Detailed studies on the ~nfiuence of cultural and environmental factors in 2,3 butanediol fermentation have been carried out by FgEE~IAN (1947), using ]~-199 strain of A. aerogenes. OLso~ and JOHNSON (1948) roported high yields of 2~ butanediol with aerated cultures of A, aerogenes, growing in dextrose solution. These studies suggest that A. aerogenes is probably the most efficient organism in the conversion of sugar into 2,3 butanediol. As a preliminary to a detailed investigation of the pathway of formation of 2,3 butanediol from sugar, a large number of strains of A. aerogenes was screened to select the best producers. A brief account of our findings is being reported, since some strains have been found to ferment sugar rapidly in surface cultures, with high yields of 2,3 butanedio].
Materials and Methods Sixty two type strains of A. aerogenes from the IKauffmann collection, State :Serum Institute, Copenhagen, were made available to us through the kind courtesy .of Department of Pathology and Bacteriology, K. G. Medical College, Lucknow. ~Strains were maintained by transfer on slants of medium containing per liter, 50 gin. tryptone, 1 gin. glucose, 5 gin. yeast extract and 15 gm. agar. Sta~4er cultures were ,developed by growing the organism for 16 hours at 30~ in a stationary medium which contained per liter, 50 gin. glucose; 0.25 gm.MgSO a -7 K~O; 0.60 gin. K~HPO4; 5.0 gin. (NHa)aSOr and 5.0 gin. CaCO 3. All ingredients excepting CaCO3 were dissolved inwater and sterilized by autoclaving at 15 psi. for 30 minutes. CaCO~ was sterilized separately and mixed with the medium before inoculation. Fermentation was carried out in 250 ml. Erlenmeyer itasks containing 50 ml. of the synthetic medium consisting of sucrose 1O0 gin.; K~HPO 4 2.5 gm.; (NH4)~S Q 4.0 gin.; :MgS04' 7tt~O 0.1 gm.; KC1 0.5 gin. and FeS0~. 7H20 0.01 gin. per liter. Salts ~ere dissolved in water and the reaction adjusted to pK 7.6. Sugar was dissolved ~eparately and these two solutions were mixed and sterilized after plugging loosely