Recyclable one-step extraction and characterization of intact melanin from alpaca fibers

Melanin, a ubiquitous natural pigment, has attracted much attention in energy and nanotechnology areas in recent years. With the increasing demand for high-quality melanin materials and sustainable experimental environment, this study was conducted to achieve melanin with intact structure through recyclable extraction method using ionic liquid (IL). Melanin extracted from base dissolution and acid isolation (BA) method and acid hydrolysis (AH) method were also used for comparison. SEM and13C-NMR characterizations indicated that IL treatment has retained the original structure of melanin while other methods caused particle damage to various degrees. In addition, the recycled IL (up to five times) showed good reproducibility, and the performance of extracted melanin at the 5th cycle was well-maintained.