To alleviate pollution and promote clean energy production, food waste can be used to produce methane through anaerobic digestion (AD). In this study, wheat straw was used to produce biochar (BC) and magnetic biochar (MB) as additives for AD of food waste. MB2.5% and BC2.5% led to the highest methane production. The main action mechanism of the additives in AD was the change in environmental factors upon stimulating microorganisms to rapidly metabolize volatile fatty acids. The stimulation of microbial function increased the abundance of the methanogenesis pathways. Methanosarcina was the most dominant archaea in the four methanogenesis modules, and the microbial community changed more clearly with time than with treatment. This study is innovative in finding the effectiveness of BC and MB treatments attributed to the abundance of methanogenesis modules, especially MB2.5% treatment retained its advantage until the later stage of digestion in AD process.

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China’s biogas industry has experienced ups and downs over the past two decades, with various challenges pointing to misplaced expectations that biogas technology is overly focused on energy production. With the promotion of China’s low-carbon strategy, a more rational and sustainable transformation strategy is crucial for the development of the biogas industry. To elucidate the sustainable development process of the biogas industry, this study applies the socio-technical transition theory and the strategic niche management (SNM) approach to understand the multi-regime interactions of biogas systems and their possible future paths. At present, the Chinese biogas industry needs to abandon the expectation of energy recovery and establish the expectation of multi-functional combination, especially including nutrient cycling. This study proposes a sustainable transformation path for the biogas industry and predicts three phases based on the type of socio-technological transformation path: a transformation path to 2030 to promote niche innovation and develop core technologies; a reconfiguration path from 2030 to 2050, which will require a lot of trials and errors; and the expansion of market share in 2050 through technology replacement. This study highlights the importance of niche experimentations and broad advocacy coalitions for the biogas industry. This research also illustrates how the transformation of China’s biogas industry can be achieved through incremental innovation with consistent policy support.