Influence of Process Parameters on Anaerobic Digestion Microbiome in Bioenergy Production: Towards an Improved Understanding

During the anaerobic digestion (AD) of waste and production of methane as an alternative fuel, unpredictability and instability of bioreactors are a challenge. Leading cause of such failure is the lack of knowledge about the microbial consortia involved in AD under different process conditions or perturbations during field applications. Over the last decade, microbiome in AD has been extensively studied with culture-independent molecular microbiology techniques, which have shed light into their structure and function. Hence, a critical discussion and consolidation of efforts made in these studies towards linking microbiome to reactor performance are required. This review focuses on how such molecular information can provide improved insight in correlation of microbiome structure and reactor performance to attain a stable and efficient AD. Studies describing microbial community dynamics under different process conditions have been briefly discussed along with the molecular approaches used. Furthermore, interesting developments toward the inclusion of diversity to mathematical modeling of AD systems are discussed. Based on the present state of the advancements, the review endeavors to critically evaluate the current knowledge gaps and research questions that must be resolved in the future in order to address the problem of instability associated with AD.