Akinmolayan, Tosin AkinBamigboye, Olutoyin OmolaraAlao, Jude OluwapelumiWilkie, Eunice DamilolaBamigboye, Favour OluwadaraAjibade, Oluwatosin Akinola2025-08-062025-08-062025-07-30Letters in Applied Microbiology, ISSN: 0266-8254 (Print); 1472-765X (Online), Oxford University Press, ovaf106-. doi: 10.1093/lambio/ovaf1060266-82541472-765Xhttp://hdl.handle.net/10292/19644The production of cellulase enzymes is crucial for converting lignocellulosic biomass into fermentable sugars, a process essential for various industrial applications. This study investigates the impact of mutagenesis on microbial growth in Pseudomonas species, specifically P. azotoformans, P. fluorescens, and P. lactis, isolated from maize cobs. Mutagenic agents including ultraviolet (UV) radiation, ethidium bromide (EtBr), and nitrous acid (NA) were used to induce mutations, and bacterial growth was assessed over eight days using Congo Red carboxymethyl cellulose medium. While EtBr mutagenesis significantly enhanced bacterial growth, particularly in P. azotoformans and P. fluorescens, with growth increases of up to 73% at 192 hours compared to wild-type strains, cellulase activity was not directly measured in this study. UV and nitrous acid treatments showed only moderate or negative effects on growth. Although EtBr, a known carcinogen, raises safety concerns, its potential for improving microbial growth suggests it could be useful in optimizing strains for industrial applications. Further studies are needed to directly measure cellulase activity and confirm the impact of these mutagenic treatments on enzyme production.© The Author(s) 2025. Published by Oxford University Press on behalf of Applied Microbiology International. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.CellulaseEthidium BromideLignocellulosic BiomassMicrobial GrowthMutagenesisNitrous Acid / UV RadiationPseudomonas31 Biological Sciences3106 Industrial BiotechnologyMicrobiology3009 Veterinary sciences3107 Microbiology3207 Medical microbiologyJournal ArticleOpenAccess10.1093/lambio/ovaf106