Evaluation of Phycocyanin Extract from Limnothrix planctonica (KU.B3) as a Natural Blue Color for Textile Screen Printing: Effects of Additive Compounds on Colorfastness and UV Stability

Natural dyes are attracting increasing attention owing to their environmental compatibility and safety profile, particularly in contrast to synthetic dyes, which may contain hazardous compounds posing risks to human health and ecosystems. In this study, crude phycocyanin extract from the cyanobacterium Limnothrix planctonica (KU.B3) was evaluated as a natural blue color for textile screen printing. The investigation encompassed the optimization of curing temperatures and assessment of colorfastness under simulated-use conditions, including washfastness, lightfastness, and rubfastness. The results indicated that a curing temperature of 110 °C represented the practical upper limit for maintaining phycocyanin chromophore stability during the screen printing process. Among the additive compound evaluated, copper sulfate conferred the greatest resistance to UV-induced fading; the compound-treated fabric retained a K/S value of 0.83 ± 0.03 following 5 h of UV exposure, representing a decline of approximately 16% compared with approximately 25% in the untreated control. However, washfastness was poor across all treatment conditions (grey scale score 1), indicating that under the binder system investigated in this study phycocyanin may be more suitable for decorative rather than washable textile applications.