Keratin from waste sheep wool could boost growth of green gram plants. Credit: Cavan Images/Alamy Stock Photo

A solvent has shown efficiency in extracting value-added proteins such as keratin and melanin from waste human hair, chicken feathers and animal wool1. The spent solvent can be recovered and reused for boosting the growth of a specific plant.

The solvent, made of tetramethyl ammonium hydroxide and water, is non-toxic to soil microbes. It could potentially be used for agricultural purposes, says a team at the CSIR-Central Salt and Marine Chemicals Research Institute in Gujarat.

Millions of tonnes of protein-rich animal biomass end up as pollutants in water bodies. To find a way to avert this, scientists, led by Kamalesh Prasad, dissolved waste human hair, chicken feathers and sheep wool in separate solvent systems. These were continuously stirred under nitrogen gas.

The human hair and chicken feathers produced keratin and melanin at room temperature, and the sheep wool made keratin at 65 0C. The feathers generated the maximum amount of keratin. After extraction, the keratin was chemically and structurally stable in the solvent systems.

Next, the researchers soaked green gram seeds in the recovered solvent in test tubes. The seeds were sown in cups and grew with significant increases in height and weight.

The researchers also found that the insoluble part of the waste animal biomass was compatible with soil microbes. It contained nitrogen and organic carbon, which could potentially be used as an organic fertilizer.