Biotechnology is increasingly being used as a tool to replace traditional production methods due to concerns about the increasing damage caused by global warming. Bacteria, yeasts, fungi, and microalgae are microorganisms able to transform residues into value-added bioproducts. They produce microbial biomass that can result in the production of several products, such as biofuels, microbial proteins, fatty acids, bioactive polysaccharides, carotenoids, industrial enzymes, polyhydroxyalkanoates, and biofertilizers, among others. To improve microbial biomass and lipid yield, modern genetic engineering techniques can be applied as a way of optimizing processes and conditions. This review aims to explore the latest trends and technological advances in microbial biomass and lipid production, including optimization strategies for cultivation conditions and the use of genetic engineering to enhance yields and efficiency. It also discusses the challenges and future prospects for scaling up production for industrial applications. The potential of microbial lipids to contribute to a sustainable bioeconomy, as well as their applications in renewable energy and food industries, underscores their importance in a world increasingly seeking alternatives to fossil fuel dependence and unsustainable agricultural practices.