Biofilm formation as a method of improved treatment during anaerobic digestion of organic matter for biogas recovery

[Display omitted] •Biofilm formation in enhanced anaerobic digestion.•Meta-analyzed results supported the effectivity of AD biofilm reactors.•Biocarrier types influenced microbial composition dynamics during AD.•Modern spectroscopy provided understanding of biofilm matrices. The efficiency of anaerobic digestion could be increased by promoting microbial retention through biofilm development. The inclusion of certain types of biofilm carriers has differentiated existing AD biofilm reactors through their respective mode of biofilm growth. Bacteria and archaea engaged in methanogenesis during anaerobic processes potentially build biofilms by adhering or attaching to biofilm carriers. Meta-analyzed results depicted varying degrees of biogas enhancement within AD biofilm reactors. Furthermore, different carrier materials highly induced the dynamicity of the dominant microbial population in each system. It is suggested that the promotion of surface contact and improvement of interspecies electron transport have greatly impacted the treatment results. Modern spectroscopy techniques have been and will continue to give essential information regarding biofilm’s composition and structural organization which can be useful in elucidating the added function of this special layer of microbial cells.