Red Pigment Formation by Interaction of Molds Part 6 Medium Components Affecting Formation of the Pigments

Abstract

It has been reported in our previous papers (1-5) that (i) the red pigments are produced by interaction of Penicillium verruculosum with Trichoderma viride or with several other strains of molds species, that (ii) the degree of pigment formation depends largely upon the balance of activities of both strains in the mixed culture, that (iii) the optimal conditions for pigment formation, such as of pH, temperature and oxygen supply coincide with those for mycelial growth, and that (iv) the process of sporulation of P. verruculosum plays the most significant role in the determining the degree of the cobiontic formation of the red pigments.The present study deals with the effects of the components of nutrients contained in the culture media, especially of carbonic and nitrogenous materials, upon the cobiontic pigment formation in question. EXPERIMENTAL METHODS(1) Microorganisms: P. verruculosum L 9 and T. viride L 6. (2) Media : Liquid or agar glucose-peptone media described in a previous paper (1).(3) Inoculation: Agar plates were inoculated with spores of the test molds using an inoculum hook, while the liquid media were inoculated with water-suspensions of the spores using a sterilized pipette. The spore suspensions were prepared as reported in the preceding paper (5). The spores of both strains which had been fully matured on the koji extract agar slant were separately suspended in sterilized water containing 0.050 of Tween 80 to make suspensions containing 108 each of spores per ml. Mixed spore suspensions were also prepared by mixing equal volumes of each suspension containing respectively, per ml. 108 spores of P. verruculosum L 9 and 5 x 108 spores of T. viride L 6. To obtain uniform inocula, the spore suspensions were shaken vigorously before they were seeded to experimental cultures.(4) Main cultures : In the case of plate cultures, as reported in previous papers (4, 5), spores of both strains were simultaneously inoculated at a distance of about 3 cm on the same plate and incubated at 30° for 3 to 7 days. 74