Chapter 12: Genetic and Process Engineering for Select Glycolipid Biosynthesis from Plant/Algal Oils or Their Derivatives^†

Microbial glycolipids, composed of fatty acid(s) linked to a carbohydrate moiety, are amphipathic surface-active molecules with numerous applications in the food, textile, and cosmetic industries, as well as in the medical and pharmaceutical industries. Glycolipids play important in vivo structural roles as components of the microbial cell surface or they may be secreted extracellularly into the growth medium. Several microorganisms are emerging as suitable sources for the renewable production of these compounds. In addition, glycolipids can be produced in abundance using inexpensive substrates and low-value agricultural feedstocks, making their commercialization prospects more appealing. However, rational improvement to strain productivity of several glycolipid-producing microbes is limited by the scant knowledge of cellular metabolism, gene regulatory mechanisms, and the environmental factors influencing glycolipid accumulation. In this chapter, known genetic and metabolic regulations involved in the biosynthesis of low molecular weight glycolipids including rhamnolipid, sophorolipid, mannosylerythritol lipid, cellobiose lipid, and trehalose lipid produced by a variety of bacteria and yeasts are discussed. In addition, knowledge available on the metabolic engineering strategies to enhance the quantity and quality of glycolipids produced from relevant microbial strains is outlined.