PEER-REVIEWED ARTICLE bioresources.com Matsunaga et al. (2013). “Polysaccharides process,” BioResources 8(1), 461-471. 461 Hydrothermal Extraction and Micronization of Polysaccharides from Ganoderma lucidum in a One- Step Process Yui Matsunaga, a,b Wahyudiono, b Siti Machmudah, b,c R. Askin, a Armando T. Quitain, a Mitsuru Sasaki a and Motonobu Goto b Ganoderma lucidum (G. lucidum) is a mushroom-forming white rot fungus that contains a wide variety of bioactive components (glucans). In this study, G. lucidum was utilized for the extraction of polysaccharides by hot compressed water at a temperature of 160 o C and a pressure of 4.0 MPa using a semi-batch system. Under these conditions, thermal softening of G. lucidum occurred, allowing the removal of the polysaccharides protecting other constituents in G. lucidum via hydrolysis. Next, the extract was directly atomized by spray drying to remove the water. Scanning electron microscope (SEM) images showed that the particles formed were spherical and dimpled or shriveled with diameters varying from 1 to 6 m. Based on these results it is proposed that this process is applicable to isolate polysaccharides from other types of biomass and may result in advances in extraction technology to obtain plant biomass components. Keywords: G. lucidum; Reishi; Polysaccharides; Hydrothermal extraction; Micronization Contact information: a: Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan; b: Department of Chemical Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan; c: Department of Chemical Engineering, Sepuluh November Institute of Technology, Kampus ITS Sukolilo, Surabaya 60111, Indonesia; *Corresponding author: mgoto@nuce.nagoya-u.ac.jp INTRODUCTION Recently, hydrothermal extraction of polysaccharides using hot water or hot compressed water (HCW) has gained much attention as an important process in the field of polysaccharide extraction (Hasegawa et al. 2004; Ando et al. 2004; Hartonen et al. 2007; Sattler et al. 2008; Yu et al. 2008; Cai et al. 2008; Dong et al. 2009; Qiao et al. 2009; Leppanen et al. 2011). Cai et al. (2008) studied the effects of hot water extraction parameters on the yield of polysaccharides from Opuntia milpa alta and obtained the optimal hot water extraction conditions. They concluded that the main components of the extracted products were isorhamnetin 3-O-(2,6-dirhamnosyl) glucoside and isorhamnetin 3-O--rutinoside. In detail, Qiao et al. (2009) reported the optimization of extraction parameters for isolation of Hyriopsis cumingii polysaccharides (HCPS) and the purification and preliminary characterization of HCPS prepared. Dong et al. (2009) also reported the optimization of hot water extraction (HWE) process of polysaccharides from cultured mycelium of Cordyceps sinensis using a Box-Behnken design, followed by canonical and ridge analyses. This process has encouraged an increase in research studies on the extraction technology of polysaccharides from a wide variety of plants or fungi due to the use of polysaccharides in immunomodulatory and anti-cancer electrochemo-