Cell Disruption and Extraction Methods for Intracellular Lipids and Proteins

Most of the microorganisms like bacteria, yeast, and microalgae have the ability to produce metabolites that are useful to human beings. These are important as they are considered natural and come under GRAS category. Important metabolites are alcohol, wine, enzymes, lipids, natural colors, organic acids, and proteins. Microbial metabolites have many advantages as the production on large scale is very cost-effective, and they can be produced easily. However, many of these high-valued biomolecules are produced inside the cells and are, therefore, known as intracellular metabolites. Therefore, to obtain these metabolites, the cells have to be disrupted. The procedure involves many steps for down streaming of the metabolite. The most important is to disrupt the cell wall. There are many different methods for cell disruption, and the selection of the method depends on the cell wall constituents, application feasibility, and the cost of the process. This chapter discusses the various methods of cell disruption/permeabilization in bacteria, yeast, and algae. There are many important factors that decide the cell disruption method in each microorganism. The major being, cell wall composition, nature of biomolecules, and the degree of purity in which the product is required to be extracted. The power consumption in the process and the level at which the product has to be scaled up are vital factors which need to be studied, before taking up the disruption method. This chapter discusses the optimization of parameters for the maximum yield of cell disruption. There are many methods like bead milling and high-pressure homogenization (HPH) that can be utilized on the large scale as they have been found to be very effective. These methods have been explained in this chapter. Energy consumption is another major aspect during downstream processing which involves the heat management . Also, the cooling systems are needed, so that the proteins do not get inactivated. All these aspects of downstream processing have been explained in this chapter.