The world’s fossil energy resources are decreasing, which has led to an increasing desire to produce fuels from organic waste to create a competitive, resource-efficient, and low-carbon sustainable economy. In natural ecosystems like rumen microbiome (RM), different activities such as hydrolysis, acetogenesis, acidogenesis, and methanogenesis of lignocellulosic biomass (LB) have been observed. These processes are carried out through physical penetration and synergistic enzyme activities that microbial communities (fungi, protozoa, archaea, bacteria, and viruses) are responsible for them. Here, microbial fuel cells act as bioreactors and microbes as biocatalysts that can directly transform chemical energy stored in LB into electrical energy. Therefore, microbiome engineering as a practical technique can enhance host performance through the selection and manipulation of specific microbial communities. It is done by leveraging scientific fundamental programs and designing quantitative methods to form microbiomes with effective functions. It promises sustainable energy production from renewable biomass. The purpose of this chapter is to review the functions, enzymatic potentials of RM and its applications for the efficient bioconversion of LB to biofuels (BFs). Finally, the current status of RM applications, diverse metabolic and genomic approaches for the development of RM bioreactors for efficient bioconversion of LBs to renewable fuels, and the challenges ahead for the practical application of bioenergy have been highlighted.