To achieve net neutrality, a sustainable circular economy approach is preferred. Amongst the available options, biological routes and especially the 'Anaerobic Fermentation' route have immense potential to contribute to net neutrality. This special issue pulls together research and review articles in this important area that can be categorized under the following three streams: (i) progressing the understanding of anaerobic digestion across disciplines; (ii) highlighting the potential for new products via anaerobic digestion; and (iii) identifying the suitable valorisation pathways for enabling a circular bioeconomy via VFAs. The implementation of these 'nature-based solutions, ' aligned with the outcomes of COP27, provides reassurance that the scientific community is advancing in the appropriate direction toward achieving net neutrality. However, transitioning from the current 'transition' mindset to the goal of 'achieving net zero' still demands substantial efforts from political, scientific, and commercial stakeholders to ensure financial sustainability and feasibility.