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Thesis (M.S.)—University of Nebraska—Lincoln, 1963. Department of Microbiology.


Copyright 1963, the author. Used by permission.


This investigation was undertaken to see if cottonseed meal could serve as the source of organic nitrogen in the B12 biosynthesis by P. freudenreichii. Corn steep liquor in 4.0g/100 ml gave the maximum yield while there was a reduction in B12 production with the decrease in concentration of liquor in the medium. On the other hand, cottonseed meal in a concentration of 4.0 gm per 100 ml produced a moderate yield of B12 which was less than the yield in the medium containing a similar concentration of corn steep liquor. There was a gradual reduction in the yield of B12 when the cottonseed meal in the medium was reduced. In Experiment 3, cottonseed meal was used to replace corn steep liquor in varying concentrations. It was found that the combination of corn steep liquor and cottonseed meal in any proportion would not significantly increase the yield of B12 over the yield obtained with cottonseed meal alone.

When cottonseed meal was added in varying concentrations, with the concentration of corn steep liquor remaining constant, there was a gradual increase in B12 production with an increase in concentration of cottonseed meal, up to three grams; then there was a sudden fall in yield of B12 when quantities of cottonseed meal above three grams were added.

Advisor: Carl E. Georgi