RED PIGMENT FORMATION BY INTERACTION OF MOLDS PART 5 FACTORS AFFECTING FORMATION OF THE PIGMENTS

Abstract

Various conditions affecting the cobiontic formation of red pigments caused by Penicillium verruculosum L 9 and Trichoderma viride L 6, were investigated and the following results were obtained.
When grown together on an agar plate the pigment formation was not affected by the initial pH in the range from 4.0 to 8.0. When grown in a liquid medium on a shaker, the optimum pH for the pigment formation was found to be at 6.0-7.0. On inoculating the spores of T. viride into precultures of P. verruculosum of varying length, it was found that the red pigment formation decreased remarkably when the preculture of the latter lasted more than 6 hours. Conversely, on inoculating the spores of P. verruculosum into precultures of T. viride of varying lengths, the amounts of the red pigments formed were almost the same as that in the control culture, except in the cases of 7 and 8hours precultures, in which the red pigment formation was considerably less. The red pigments were scarcely produced when the ratio of inoculum sizes (spores) of P. verruculosum to T. viride, was 5: 1-15:1, while a distinct pigment formation occurred when the ratio in question was 1:5-1:15.
Vigorous aeration of the culture medium was necessary for the red pigment formation and it was inferred that a close relation may exist between the sporulation of P. verruculosum and the cobiontic red pigments formation. The red pigments were produced over the temperature range of 20° to 30° where both test molds could grow well, the optimal temperature being found in the range of 25° to 30°.