Water‐soluble red pigments from Isaria farinosa and structural characterization of the main colored component

Abstract

The present study describes the red pigment synthesized by the filamentous fungi Isaria farinosa under submerged culture conditions. The pigment production was optimal under the following conditions: pH 5, agitation speed 150 rpm, temperature 27 °C, incubation time 192 h, light source total darkness, sucrose and glucose as carbon source, yeast extract, meat peptone and monosodium glutamate at a fixed concentration of 3% as nitrogen source. The addition of 10 mM CaCl 2 to the culture medium increased the biomass and pigment production. Structural elucidation of the pigment using gas chromatography-mass spectrometry, Fourier transform infrared spectroscopy and 1 H nuclear magnetic resonance spectroscopy revealed that the red pigment contains an anthraquinone-related compound. In addition, the isolated pigment was water soluble, and was stable when exposed to salt solution (96.1% of stability after treatment with sodium chloride), acid (72.1% with citric acid), heat (86.2% at 60 °C), and sunlight (99.4%). These results are promising to further exploit the fungal culture of Isaria farinosa for producing the red pigment and, subsequently, to considerably increase its yield. The study has commercial importance in the production of Isaria farinosa pigment for industrial application after considerable toxicological examination.

Fungal Pigments and Their Prospects in Different Industries

“…Cordyceps farinosa Anthraquinone derivative [73] Ophiocordyceps unilateralis (Formerly Known as Cordyceps unilateralis)…”

“…(Figure 8b) [25]. Also, the genera belonging to the family Cordycipitaceae such as Torrubiella, Cordyceps, Beauveria, Hyperdermium, and Lecanicillium have been revealed to be promising producers of bioactive pigments, e.g., tenellin and bassianin are reported from Beauveria bassiana and Beauveria brongniartii (formerly known as Beauveria tenella), pyridovericin and pyridomacrolidin from Beauveria bassiana, torrubiellones A-D from the genus Torubiella, oosporein from Lecanicillium aphanocladii, whereas anthraquinone-related compounds are reported from Cordyceps farinosa (formerly known as Isaria farinosa) (Figure 9a) [41,[73][74][75]125]. Similarly, the pigments erythrostominone, 4-O-methyl erythrostominone, deoxyerythrostominone, deoxyerythrostominol, epierythrostominol, and 3,5,8-TMON (3,5,8-trihydroxy-6-methoxy-2-(5-oxohexa-1,3-dienyl)-1,4-naphthoquinone) have been reported from Ophiocordyceps unilateralis (formerly known as Cordyceps unilateralis), and skyrin from Hyperdermium bertonii (Figure 9a) [25].…”

“…(a) Pigments from members of the families Cordycipitaceae (species of Beauveria, Torrubiella, Cordyceps, Hyperdermium, and Lecanicillium) and Ophiocordycipitaceae (Ophiocordyceps sp. ), re-drawn from[25,41,[73][74][75]125]. (b) Pigments known from other groups of fungi (species of Chlorociboria, Scytalidium, and Epicoccum), re-drawn from[37,41].…”

Isolation and identification of Talaromyces purpurogenus and preliminary studies on its pigment production potentials in solid state cultures

“…On the other hand, too little cell inoculum will result in sluggish growth and inefficient nutrient utilization. Velmurugan et al (2010a) also reported that spore inoculum concentration of 4 ml containing 6×10 5 spores/ml was the best for inoculation of 5 g of substrate for solid state fermentation. General et al (2014) reported optimum inoculum volume of 1.8×10 6 spores per gram solid substrate during pigment production by Talaromyces amestolkiae using macroalgal biomass as the substrate.…”

Natural hydroxyanthraquinoid pigments as potent food grade colorants: an overview

“…More recently, a red pigment produced by a strain of Isaria farinosa was recently elucidated as a chromophore of the anthraquinone type 105 . Similarly, the red pigment produced by Paecilomyces sinclairii, which was beforehand discovered but uncharacterized 106 , is certainly of an identical chemical nature, i.e. an amino group linked to an anthraquinone structure 105 .…”