biomethane Technology: general issues 6 biogas 5 bioenergy 3 biorefinery 3 circular economy 3 pretreatment 3 sustainability 3 History of engineering & technology 2 anaerobic digestion 2 artificial neural networks 2 biochemical methane potential 2 bioethanol 2 biomass 2 environmental sustainability 2 fermentation 2 inhibition 2 innovation 2 methane 2 renewable energy 2 saccharification 2 100% renewable energy scenarios 1 ADM1 1 America Latina 1 Asia Pacific 1 B. ceiba 1 BIPV window 1 Biotechnology 1 CO2 emission 1 COVID-19 1