Coupling chemical degumming with enzymatic degumming of ultrasound pre-treated ramie fiber using Bacillus subtilis ABDR01

Abstract

In this study, we designed, developed, and optimizedan enzymatic fiber degumming process. First, a Partially Purified Enzyme Solution (PPES) containing pectinase, cellulase and xylanase was co-produced via ultrasound-assisted fermentation of orange peels using Bacillus subtilis ABDR01. Then, degumming with PPES was optimized for pH, temperature, incubation time and PPES concentration. Finally, three sets of ultrasound-assisted degumming experiments — chemical, enzymatic, and coupled enzymatic-chemical degumming with reduced alkali concentration (0.5% NaOH, 30 min) were performed. Chemical degumming for 2 h with 1% NaOH at 98 °C resulted in residual gum content of 5.9%, whereas ultrasound-assisted (30 min, 25 kHz) chemical degumming reduced the gum content to 3.1%. At a pH of 7.5, temperature of 45 °C, 30 h incubation and 2% PPES, gum removal efficiency of >60% and fibers with <10% residual gum were produced. Coupling the ultrasound-assisted enzymatic degumming with reduced alkali chemical degumming resulted in gum content of <3%. • High frequency ultrasonicaton pre-treatment improves fiber degumming. • Combining enzymatic and chemical degumming reduced NaOH demand. • Optimized the ultrasound-assisted enzymatic degumming of Ramie fibers. • Fibers (ø 0.05 mm) containing < 3% gum and high tensile strength produced.