Trend of ramie industry development: A review of green degumming and the utilization of processing residues

Ramie is an important industrial fiber crop with a long history of cultivation. In recent years, there has been a serious decline in the planting and processing of ramie. The current industry stagnation is largely due to the pollution caused by degumming and the low level of competitiveness of ramie textiles. This paper outlines the research advances on green degumming and high-value usage of ramie residues. When compared to traditional chemical degumming, biological degumming technologies consume 50% fewer chemical reagents and cost 78% less to treat wastewater. The oxidative degumming technology produces wastewater with chemical oxygen demand at 17000 mg/L, about 2.6 times that of wastewater by biological methods. Solvent degumming is environmentally friendly, however, the cost of the solvent and inefficient solvent recovery is still a challenge for its industrial application. Phenolic acids and flavonoids in the roots and leaves of ramie have shown good performance in the treatment of hepatitis, cancer, and cardiovascular diseases. Moreover, decorticated stalks, degumming wastewater, and other ramie residues have also exhibited a good application prospect. In conclusion, biological degumming technology and the high-value utilization of ramie residues are anticipated to solve the current difficulties faced by the ramie processing industry.