**4. Conclusion**

Bioenergy will be the most important sustainable energy source in the coming decades since it provides a cost-effective substitute to fossil fuels. The availability of low-cost biofuel and a wide range of viable forms of biofuel for the generation of heat, steam, electricity, and gas, as well as for use as a transportation fuel, will be critical to the growth of bioenergy. Many different sources, such as crops, grasses, leaves, manure, fruit and vegetable wastes, algae or other lignocellulose biomass can be used, and the procedure can be done on both small and large scale. This enables the production of biofuel everywhere in the entire globe. Significant advancements in process performance of existing technologies, as well as the establishment of novel techniques for biomass conversion, mixing, process monitoring, and process control, are required for further biofuel facility development. However, the major concern is lowering the cost of biofuel synthesis. Consequently, the biorefinery concept is required to more thoroughly exploit sustainable biomass and to produce additional value-added coproducts (e.g. bio-based products from lignin) that would lower the cost of biofuel synthesis. As a result, biofuel will be more cost efficient than fossil fuels to enhance effective transition to bioeconomy.
