Lignocellulosic biomass serves as a cornerstone in the realm of renewable energy sources. Implementing a circular economy by utilizing lignocellulosic waste as a renewable resource has the potential to reduce reliance on fossil-based resources. Over the past decade, significant research has been conducted on microbial treatment by utilizing microbes, fungi, engineered microbes, and enzymes for processing lignocellulosic biomass. The biological treatment approach outperforms other methods due to its application in milder conditions, minimal corrosiveness, and minimal byproduct formation. This significantly reduces the lignin content and crystalline nature of the lignocellulosic biomass, thereby enhancing the hydrolysis and production of monomers. Additionally, the utilization of bio-based products derived from lignocellulose has emerged as a clean product to complement fossil-based resources. This chapter focuses on discussing biological agents that promote the biodegradation of wastes. The advanced utilization of lignocellulosic biomass in various industries plays a crucial role in the bio-based economy. It encompasses innovative design and advanced production strategies to promote the industrial recovery and reuse of waste materials.