An explosive, common-source outbreak of pneumonia caused by a previously unrecognized bacterium affected primarily persons attending an American Legion convention in Philadelphia in July, 1976. Twenty-nine of 182 cases were fatal. Spread of the bacterium appeared to be air borne. The source of the bacterium was not found, but epidemiologic analysis suggested that exposure may have occurred in the lobby of the headquarters hotel or in the area immediately surrounding the hotel. Person-to-person spread seemed not to have occurred. Many hotel employees appeared to be immune, suggesting that the agent may have been present in the vicinity, perhaps intermittently, for two or more years.

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The periplasmic hydrogenase of Desulfovibrio desulfuricans was isolated and purified. Cells were washed with Tris-EDTA and the enzyme precipitated from the wash with ammonium sulfate. Absorption chromatography on DEAE and hydroxyapatite yielded the enzyme at better than 95% purity as judged by gel electrophoresis. The hydrogenase catalyzed the production of more than 9000 mumol H2/min mg protein(-1) from reduced methyl viologen at 37 degrees C. It is very stable and resists inactivation by heat (50% activity remained after 5 min in air at 65 degrees C) and by enzyme inhibitors (except N-ethylmaleimide and potassium ferricyanide). After storage in air at 4 degrees C for 1 month no activity was lost. The enzyme activity is sensitive to ionic environmental changes. With methyl viologen the optimum pH was 5.5 but with p-xylene polymeric viologen the optimum was about pH 7 but less sharp. The molecular weight was 47 X 10(3)(+/- 2 X 10(3), 52 X 10(3)(+/- X 10(3), and 56 X 19(3)(+/- 2 X 10(3) by SDS-gel electrophoresis, gel chromatography, and sedimentation equilibrium, respectively, and the isoelectric point was at pH 6.0. They enzyme might be useful in the production of hydrogen from water and solar energy.

The conversion of ethanol to ethyl acetate has an advantage as a method of ethanol recovery since ethyl acetate is amenable t o simple solvent extraction. The potential of Candida utilis in this conversion was studied. The kinetics of accumulation of ethanol and ethyl acetate in glucose-grown C. utilis showed that ester formation resulted from ethanol utilization under appropriate aeration and was inhibited by Fe3+ supplementation. Candida utilis converted ethanol to ethyl acetate optimally at pH 5.0-7.0. The five-hour rate of ester production increased as the ethanol concentration increased to 10 glL, and rapidly declined to zero at concentrations exceeding 35 glL. Thus, C. utilis has potential to recover dilute ethanol in the form of ethyl acetate.

Cells of Serratia marcescens, whether pigmented or unpigmented, contained 10–11% of methanol–chloroform extractable lipids (dry weight basis) and < 1% of bound lipids. The extractable lipids contained 34–43% phosphatides, 3–11% unsaponifiable material, and 2–5% free fatty acid. The phosphatides contained high proportions of phosphatidyl ethanolamine and smaller amounts of phosphatidyl serine, polyglycerol phosphatides, phosphatidyl glycerol, and an unidentified ninhydrin-positive phosphatide probably associated with ornithine and other amino acids found in the lipid hydrolyzate.The fatty acids were found to consist largely of palmitic, C17- and C19-cyclopropane and C16- and C18-monoenoic acids. The proportions of monoenoic and cyclopropane acids were found to vary greatly with the age of the cultures; in the early stages of growth, regardless of pigmentation, low amounts of cyclopropane acids and high amounts of monoenoic acid were present, the latter being converted almost completely to cyclopropane acids during the active growth phase.The lipids associated with extracellular lipopolysaccharide material were similar in composition to the cellular lipids.

A standard vegetative inoculum of Aspergillus niger has been developed for the submerged citric acid fermentation of sugar beet molasses. Increasing the ferrocyanide content and the pH of the seed mash, within limits, decreased the rate of development of the mold pellets whereas increasing the spore inoculum increased the rate of development. Using this "standard" inoculum, an average yield of 8.9% anhydrous citric acid (68.5% conversion of available sugar) was obtained in 116 hr. The standard deviation between runs was 4.5% of the mean citric acid yield. An abrupt breakdown of the fermentation process decreased the yield by 50% and increased the standard deviation to 28.5% of the mean yield. The breakdown was overcome by changing the sporulation medium from a chemically-defined synthetic type to a nutritionally-richer type. Results indicate that serial transfer on a synthetic medium weakened the culture and made the fermentation unstable.