## 1 Introduction  
The beer production industry generates large amounts of valuable by-products with many biological and functional values. Spent brewer's yeast is such by-product that could be used as raw material for \(\beta\)-glucan extraction since the most important polysaccharides found in cell walls are glucan and mannan with linear bonds at \(\beta\)-(1-3)/(1-6), the most frequent being the \(\beta\)-(1-3) [1]. In the literature, there are various methods of cell lysis that can be implemented for yeast extraction, depending on the cellular components that should be isolated. Thus, for total protein extraction, improved methods, such as the one described by [PERSON] et al. (2011) using lithium acetate (LiAc) in combination with NaOH, which enhances the permeability of yeast cell walls, releasing proteins from cells, could be used [2]. In contrast, for lipid extraction, the homogenization of a cell suspension in the presence of organic solvents and glass beads with a diameter of 0.25-0.30 mm can be effective, according to the data presented by [PERSON] and [PERSON] (2006) [3]. The authors showed that the method allows cell disruption over four cycles of 30 s at 1700 rpm with a pause of 30 s between cycles. Regarding the extraction of polysaccharides that are mainly found in cell walls, first, it should be considered whether whole particles or fragments of \(\beta\)-glucans should be obtained. One of the methods to extract \(\beta\)-glucans involves cell fragmentation that occurs by using glass beads or ultrasound. Some more complex methods include the use of ultrasound, alkaline substances, and enzymes in combination for the extraction of \(\beta\)-glucans [4]. The extraction from spent brewer's yeast is slightly different compared to extraction from native yeast. The environment in which the yeast lives and the growing conditions have special implications in the resistance and polysaccharide content of the cell wall. Thus, a deficiency of nutrients in the environment can lead to an increase in \(\beta\)-glucans in the yeast cell wall [5]. In general, each one of 13-25 serial repitchings of yeast cells involves 2-3 rounds of cell division [6]. Considering the number of successive replications, as well as the composition of the environment in which cell division takes place, yeast will develop a resistance to the environment that is expressed by an increase in thickness and a deformation caused by budding scars on the cell surface. Such changes in the thickness of the cell wall of spent brewer's yeast are observed by using transmission electron microscopy (TEM) [7]. One of the most efficient and reliable methods of breaking the cell wall is agitation with glass beads, which achieves breakage in a relatively short time, and the continuous kinetic energy generates sufficient mechanical energy to disrupt yeast cell walls [8; 9]. This complex process allows a rapid release of cytoplasmic content in the reaction phase and fragments of cell walls can be easily separated by centrifugation [10]. The critical parameters, such as mechanical agitation speed, glass bead loading, suspension concentration, and glass bead size, are factors that influence the rate of cell rupture with direct effect on the concentration in the final \(\beta\)-glucan content. [PERSON], [PERSON], and [PERSON] (2016) stated in a brief presentation of cell rupture methods that the optimal size of glass beads for yeast cell lysis would be a large diameter of 0.5 mm because beads with small diameters are used especially for bacteria [11]. Beads smaller than 0.25 mm in diameter are not suitable for yeast, and a particular diameter between 0.1-0.15 mm is used for microbial cells [12]. In a more elaborate study investigating the kinetic effect of cell disruption, which admits as variables the operating time (0-3 min), bead loading (0.3-0.85 volume ratio), bead diameter (0.375-0.875 mm) and agitation speed (2000-6000 rpm), stated that an increase in bead loading up to 0.85 and a bead diameter of 0.375 mm will speed up the rate of cell rupture [13].