Agro-Industrial Coproducts as Sustainable Substrates for Colorant Biosynthesis by Talaromyces sp.

Natural colorants derived from filamentous fungi have gained increasing attention as safe, sustainable, and bioactive alternatives to synthetic counterparts. This study evaluated the red colorant production by Talaromyces sp. under solid and static submerged culture conditions, focusing on the selection of carbon and nitrogen sources and the influence of the inoculum’s physiological state. In solid-state cultivation, oat-based medium and Potato Dextrose Agar (PDA) supplemented with glycine (PDAG) promoted intense sporulation and red–yellow pigmentation, whereas sugar-rich media, specifically Yeast Extract Sucrose (YES) and Sabouraud Agar, led to rapid mycelial growth but reduced sporulation. Radial growth rates ranged from 0.295 to 0.391 cm/day, depending on the growth medium. YES medium supported the fastest growth; however, it was ineffective in promoting colorant induction when used as an inoculum source for liquid culture. Under static submerged fermentation conditions, inoculum derived from PDAG and PDA supplemented with yeast extract (PDA + YE) produced the highest colorant titers, highlighting that the inoculum developmental stage is a key determinant in activating azaphilone colorant biosynthesis. Additionally, commercial sucrose and sugarcane juice were identified as the most effective carbon sources, outperforming lignocellulosic hydrolysates from sugarcane bagasse, rice, and corn. A preliminary economic analysis estimated production costs ranging from US$ 3.11 to US$ 3.34 per liter of colorant. A Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis revealed key strengths such as high colorant productivity, alongside significant opportunities in the natural ingredients market. Overall, these findings underscore the technical and economic potential of Talaromyces-based biocolorant production, positioning it as a sustainable and competitive alternative to synthetic colorants.