A comprehensive review on anaerobic digestion with focus on potential feedstocks, limitations associated and recent advances for biogas production.

With the escalating energy demand to accommodate the growing population and its needs along with the responsibility to mitigate climate change and its consequences, anaerobic digestion (AD) has become the potential approach to sustainably fulfil our demands and tackle environmental issues. Notably, a lot of attention has been drawn in recent years towards the production of biogas around the world in waste-to-energy perspective. Nevertheless, the progress of AD is hindered by several factors such as operating parameters, designing and the performance of AD reactors. Furthermore, the full potential of this approach is not fully realised yet due the dependence on people's acceptance and government policies. This article focuses on the different types of feedstocks and their biogas production potential. The feedstock selection is the basic and most important step for accessing the biogas yield. Furthermore, different stages of the AD process, design and the configuration of the biogas digester/reactors have been discussed to get better insight into process. The important aspect to talk about this process is its limitations associated which have been focused upon in detail. Biogas is considered to attain the sustainable development goals (SDG) proposed by United Nations. Therefore, the huge focus should be drawn towards its improvements to counter the limitation and makes it available to all the rural communities in developing countries and set-up the pilot scale AD plants in both developing and developed countries. In this regard, this article talks about the improvements and futures perspective related to the AD process and biogas enhancement.