Effect of stress on growth, pigment production and morphology of Monascus sp. in solid cultures

Abstract

The aim of the current work was to study the influence of stress on pigment production in Monascus purpureus under solid-state fermentation. Thermal stress was induced by incubating the culture at various high temperatures. For giving osmotic stress, different concentration of NaCl and glycerol were added to the solid substrate prior to autoclaving. Morphological studies were done by light microscopy and scanning electron microscopy. When the cells were exposed to high temperature, high glycerol and salt concentration, significant changes in pigment production and growth were observed. High temperature (>45 degrees C) induced the production of more yellow pigments. High concentration of NaCl induced conidiation and caused a decrease in fungal biomass (up to 50%) but red pigment production increased from 11.86 OD/gds to 20.14 OD/gds. When subjected to glycerol stress, a significant increase in aerial mycelia was observed when compared with the control conditions. The results attain significance for exploiting the fungal culture of Monascus purpureus LPB 97 for producing colors of choice--red, or yellow, or increasing the yield of red pigments considerably. Thus, these results could well impact the commercial aspect of Monascus pigments for industrial application.

Spectrophotometric detection of Pigments from Aspergillus and Penicillium isolates

“…Hence, this technique may also be used for the chemotaxonomic analysis of fungal metabolites. Spectroscopic analysis of both crude and purified fungal pigments have been reported for qualitative and quantitative detection [11,18]. The present study clearly demonstrated production of pigments by fungal strains tested.…”

“…All other fungi did not show chloroform soluble pigments secreted into the medium. The nutrients and culture conditions greatly influence pigment production in fungi [18,19]. In case of ethyl acetate as solvent, Penicillium isolate DUMB11 showed light yellow cellular pigment when grown in PDB.…”

Production of food colourants by filamentous fungi

“…Reports on the effects of temperature on cell growth and pigment production by various species of fungi indicate that the optimum temperature ranges from 24 to 30°C regardless of the strain (Table 5). However, Babitha et al (2007) reported that high temperature greater than 45°C resulted in production of high concentration of yellow pigments by Monascus sp. Generally, it is known that temperature affects the membrane fluidity and thus, the uptake of nutrients and excretion of products by microorganisms.…”

“…Scytalidium cuboideum pigmented both wood species at moisture content above 35%. Even for the same M. purpureus, the optimum moisture contents varied between 42 and 60% (Lee et al, 2002;Babitha, 2007;Velmurugan et al, 2011;Yongsmith et al, 2013). On the other hand, Said et al (2010) reported that maximum pigment concentration and productivity by M. ruber ICMP 15220 were obtained under an initial moisture content of 70%.…”

Production of angkak through co-culture of Monascus purpureus and Monascus ruber

“…Monascus species under monoculture conditions showed that secondary metabolites production is greatly affected by fermentation medium, cultivation conditions and types of Monascus species used in the fermentation process (1,5,13,21,23). Increasing concentration of lovastatin in angkak was a prime area of research in order to produce high quality bio-*Corresponding Author.…”