Ultrasound-Assisted Extraction (UAE) of Polysaccharide from Dried Biomass of Sargassum muticum

Abstract

The study was aimed at ascertaining the various factors and experimental conditions affecting extraction efficiency and polysaccharide yield from dried biomass of Sargassum muticum using ultrasound- assisted extraction. The different factors investigated include sample size, nature of solvent, solid-solvent ratio, sample pre-treatment, particle size, solvent composition, ultrasonic horn types, horn immersion depth, extraction time, electrical acoustic intensity and temperature. Factors positively affecting the extraction outcome were identified as sample size, solvent composition, horn type, horn immersion depth, extraction time and amplitude. Selection of 0.03 M HCl solution as extractant played an important role in improving extraction efficiency. Two-stage extraction is found to have an advantage over single- stage treatment leading to improvement in extraction yields. Pulsed ultrasound treatment was found to be highly effective as opposed to continuous treatment. Optimization of the factors led to the development of a rapid, highly effective, low- solvent consuming, energy -efficient approach, yielding 24.83 + 1.28 g% (on dry weight basis) of the polysaccharide which is at least 3.5 times higher than the reported yields of 7 g% on dry weight basis. Extraction yields, extraction time and solvent volumes were compared with conventional extraction technique. Conventional extraction technique employing hot reflux yielded 11.08 + 0.78 g% (dry weight) of the polysaccharide after three cycles of treatment.