RESULTS AND DISSCUSSION Morphological description of M. purpureus Monascus purpureus (Went) is a homothallic fungus belongs to the group of Ascomycetes (family Monascaceae). Growth on potato dextrose agar medium (PDA), mycelium is white in the early stage then rapidly changes to a rich pink with soluble pigment diffuse in medium (A). Pedicellate ascomata with ascospores (B &C). Monascus purpureus produced spherical ascospores of 5 microns in diameter (D) as shown in fig.1. Spectral analysis of M. purpureus red pigment Spectral analysis of pigments produced by M. purpureus on corn starch medium shows absorbance peaks at 420–430 and the highest peak was at 500nm (Fig. 2). In agreement with our results; Silveira et al (2011) found that spectral analysis of pigments …show more content…
8). The optimum ionic strength for red pigment production by M. purpureus was 1% NaCl. These results may be due to the increasing of electrolyte concentrations in saline environments tending to inhibit metabolic functions of the cells (Adler et al. 1982). The highest growth and red pigment production obtained from medium containing amino acid was L- tryptophan (4.75 ± 0.09 A500) and maximum dry cell mass was (3.9 ± 0.02 g/l) as shown in fig. 9. Juzlova et al (1996) described that amino acid addition in growth medium of Monascus lead to increase red pigment production than other pigment. Metal ions additions showed a great effect on Monascus both growth and red pigment production (Fig. 10). Weinberg (1989) stated that trace metals have stimulatory effects on secondary metabolism. Metal ions, Fe2+, Zn2+ and Mg2+ showed strong effect on both growth and pigments production of Monascus sp. (Lin and Demain 1993; Lee et al.