_____________________________________________________________________________________________________ *Corresponding author: E-mail: anulinwachukwu08@gmail.com; Asian Journal of Biotechnology and Bioresource Technology 8(3): 16-22, 2022; Article no.AJB2T.87398 ISSN: 2457-0125 Effect of Fungal, Bacterial and Alkaline Augmentations on the Biogas Composition of Selected Plant-based Substrates Augusta Anuli Nwachukwu a* , Toochukwu Ekwutosi Ogbulie a,b , Harriet Chinyelu Nwigwe a , Ernest Anayochukwu Anyalogbu a and Henry Uzoma Anuforo c a Department of Biotechnology, School of Biological Sciences, Federal University of Technology, Owerri, Imo State, Nigeria. b Afrian Centre of Excellence in Future Energies and Electrochemical Systems [ACE-FUELS], FUTO, Nigeria. c Department of Biology, School of Biological Sciences, Federal University of Technology, Owerri, Imo State, Nigeria. Authors’ contributions This work was carried out in collaboration among all authors. All authors read and approved the final manuscript. Article Information DOI: 10.9734/AJB2T/2022/v8i330126 Open Peer Review History: This journal follows the Advanced Open Peer Review policy. Identity of the Reviewers, Editor(s) and additional Reviewers, peer review comments, different versions of the manuscript, comments of the editors, etc are available here: https://www.sdiarticle5.com/review-history/87398 Received 07 April 2022 Accepted 14 June 2022 Published 20 June 2022 ABSTRACT Lignocellulosic residues are interesting sources of renewable energy, if only their biomass recalcitrance could be reduced through appropriate pretreatment technologies and augmentations, to enhance anaerobic digestion. This study aimed at assessing the effects of bacterial, fungal and alkaline augmentations, on the biogas composition of selected plant-based substrates, namely: maize cob , rice straw and water hyacinth. Standard methods were adopted; the substrates were mechanically pretreated, loaded in single, dual and composite combinations, into five 54 L capacity metallic batch anaerobic digesters. Codigestion was encouraged with the addition of cow rumen waste. The set ups were allowed to run for 42 days under mesophilic conditions, while stirring daily. The biogas composition namely: methane, carbon IV oxide and hydrogen sulfide concentrations were measured on the 42 nd day. The results showed that the composite with the Original Research Article