01211naa a2200169 a 450000100080000000500110000800800410001910000150006024500720007526000090014752007610015665000160091765000160093365000100094965300270095977300550098616466362023-03-30       1932    bl uuuu     u00u1 u    #d1 aPORGES, N.  aCitric acid production by aspergillus niger.h[electronic resource]  c1932  aA strain of Aspergillus niger which had been isolated from the soil was studied as to its ability, to produce citric acid in a sugar solution, and an increase in o.iN titratable acidity from 30 cc. to 500 cc. per 100 cc. culture solution was obtained by the modification of the original solution. Sugar concentrations of 15 to 20 percent were necessary for high yields of citric acid, although the sugar was not completely used. A 5 percent concentration of sugar gave small yields of citric acid, as this acid was used as an energy source by the organism. As a source of nitrogen, NaNO3 was far superior to NH4NO3 or (NH4)2SO4 for citric acid production. The presence of iron and zinc was essential for rapid growth and increased citric acid accumulation.  aAminoácido  aNitrogênio  aZinco  aConcentracao de acucar  tAmerican Journal of Botanygv.19, p.559-567, 1932.