Natural dyes were the main colorants for textiles through the 19th
century (1). Since then synthetics have almost completely replaced
natural dyes. The wide range of available colors, greater reproducibility,
improved quality of dyeing, and economic benefits of synthetic
dyes are highly desirable. However, it is well known that some of the
synthetic dyes are environmental toxins and negatively impact
ecosystems. Recent studies reported that 10–35% of these dyes are
lost in wastewater during the dyeing process (2,3). Due to serious
environmental pollution concerns, textile industries are facing
extensive problems and several have banned various synthetic
coloring agents. Consequently there is a growing demand for ecofriendly,
non-toxic colorants for industrial applications.
Natural dyes or pigments are an important alternative to
potentially harmful synthetics (3). Numerous studies report that
microorganisms of the genus Monascus produce red pigments, which
are used as coloring agents in food and textiles (4–6). Moreover, in
several Asian countries, Monascus species are grown on rice grains,
and used for coloring some foods (7), increasing the demand for the
highly safe pigments. However, the high cost of the current liquid
culture-based fermentation technology has limited the industrial use
of Monascus pigments. Thus, there is a growing need for low cost
production of natural pigments or coloring agents.