Synergized enzyme-ultrasound-assisted aqueous two-phase extraction and antioxidant activity validation of polysaccharides from tobacco waste

Abstract

A powerful and innovative technique was developed to efficiently extract and refine polysaccharides from tobacco waste. This was achieved through a combination of enzyme and ultrasound-assisted extraction assisted aqueous two-phase extraction (EUAATPE). The formation of an aqueous two-phase system (ATPS) using various salts and ethanol was investigated. ATPS of 18.0 % (NH4)2SO4 (w/w) and 25.0 % ethanol (w/w) was chosen due to its favorable selection extraction ability and high recovery of 93.68 ± 0.40 %. By utilizing both single-factor experiments and response surface method (RSM), the key factors involved in the EUAATPE process were optimized. The optimal conditions were as follows: ultrasonic power 180 W, ultrasonic time 9 min, cellulase concentration 2.0 %, pectinase concentration 1.0 %, extraction temperature 50 °C, extraction time 1.5 h, and liquid-to-solid ratio 30:1 (g/g). Under the optimal conditions, the extraction yield of polysaccharides was 6.72 ± 0.11 (mg/g), and the purity of the polysaccharides from the bottom phase was 78.73 ± 3.17 %. EUAATPE resulted in a significant enhancement in the extraction yield and purity of polysaccharides from tobacco waste compared to traditional methods such as hot water extraction (HWE), ultrasound-assisted extraction (UAE) and enzyme-assisted extraction (EAE). Polysaccharides of tobacco waste obtained from various methods had analogous monosaccharide compositions, different molar ratio compositions and surface structure characteristics. Moreover, all polysaccharides exhibited a certain extent antioxidant activities and polysaccharides from the bottom phase (PBP) extracted by EUAATPE showed superior antioxidant activity. Hence, EUAATPE, being an innovative and eco-friendly extraction technique, presents a productive substitute for extracting and refining polysaccharides from discarded tobacco resources.