Chapter 11 - Lipids production using agricultural residues

Abstract

The lipids production process involves many steps such as the selection of media components, cultivation of oleaginous microorganisms, lipid accumulation, biomass harvesting, and finally leach out of lipids. Agro-waste is an interesting renewable resource for sustainable biodiesel production because of its rich source of carbohydrates. Therefore, to make this process economical is to replace readymade lipid precursors (glucose and xylose) with extracted sugars from agro-waste. The biological pretreatment and enzymatic hydrolysis of agro-waste can make this process cost-effective if in-site enzyme production and potential enzyme cocktail preparations are done. The most important concern about this process is the complexity of the microbial cell wall that limits the full recovery of intracellular lipids. Generally, there are no perfect recovery techniques for different oleaginous species (yeast, fungi, and microalgae). Each method has a different mechanism to disrupt cells for lipid extraction; hence a well-planned evaluation of the method is crucial before implementation. In this study, mechanical (ultrasonication, bead milling, microwave, and homogenization) and nonmechanical (chemical digestion, osmotic shock, and enzyme-assisted) are discussed to evaluate their feasibility. Recent technologies such as automated pressurized liquid extraction (APLE), supercritical fluid extraction (SFE), and in situ simultaneous lipid extraction using adsorbent-based oil capturing components are analyzed to expedite the option of highly fruitful lipid recovery processes.