Biomass, one of the oldest sources, derives its energy from the sun through photosynthesis, making it a renewable and abundant resource. It plays a significant role in developing and developed countries, supporting energy needs for cooking, heating, and electricity generation. Biomass sources include wood, agricultural waste, solid waste, and landfill gas, contributing to biofuel production and energy generation. Several microbial enzymes help in fermenting sugars in biofuel. However, to fulfill the increasing demand for energy, specific enzymes that play a major part in biomass conversion can be engineered in microbes. Metabolic engineering enhances microbial pathways to optimize biomass conversion, targeting enzymes, cofactor availability, and microbial tolerance to inhibitory by-products. Genetic engineering strategies, including heterologous pathway introduction and the CRISPR-Cas9 technique, improve the efficiency of biomass degradation and biofuel production. This chapter is focused on various enzymes involved in biomass conversion and potential engineering approaches that might be beneficial to meet the energy requirement through biomass.