Journal of Bioscience and Biotechnology Discovery Volume 8(2), pages 34-40, April 2023 Article Number: 19B355683 ISSN: 2536-7064 https://doi.org/10.31248/JBBD2023.174 https://integrityresjournals.org/journal/JBBD Full Length Research L-glutamic acid production by immobilized wild and mutant Bacillus species Durojaye O. T. 1 *, Adebayo-Tayo B. C. 2 and Onifade A. D. 3 1 Department of Biological Sciences, Dominion University, Ibadan, Oyo State, Nigeria. 2 Department of Microbiology, University of Ibadan, Ibadan, Oyo State, Nigeria. 3 Department of Science Laboratory Technology, The Polytechnic Ibadan, Ibada, Oyo-Satate, Nigeria. *Corresponding author. Email: o.durojaye@dominionuniversity.edu.ng Copyright © 2023 Durojaye et al. This article remains permanently open access under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Received 2nd February 2023; Accepted 28th March 2023 ABSTRACT: The effect of Ultra-Violet (UV) irradiation and acridine orange dye on L-glutamic acid producing Bacillus subtilis and B. megaterium was investigated. The selected mutant strains and wild types of B. subtilis and B. megaterium were immobilized and used for L-glutamic acid production. The Bacillus strains were exposed to UV irradiation and treated with acridine orange dye respectively. The survived Bacillus strains were found to reduce as the exposure time and concentration of the mutagens increased in this study. Four mutants of B. subtilis and two mutants of B. megaterium were selected for L-glutamic acid production. Mutant strain of B. subtilis (MAIR4) treated with acridine orange dye yielded the highest L-glutamic acid (4.62 mg/mL) at 72 hours. L-glutamic acid production by mutant wild and strains of B. subtilis and B. megaterium immobilized on sodium alginate, Agar-agar matrix and poly urethane foam ranged from 1.65 to 4.03 mg/mL, 2.04 to 3.98 mg/ mL and 1.89 to 3.39 mg/mL, respectively with B. megaterium (MUSO17) on sodium alginate producing the highest L-glutamic acid. Sodium alginate was the best supporting matrix for the production of L-glutamic acid in this research. Immobilization of mutant strains of Bacillus megaterium (MASO17) exposed to UV irradiation using sodium alginate supported the L-glutamic acid production. Keywords: B. subtilis, B. megaterium, immobilization, L-glutamic acid, mutation, polyurethane foam (PUF). INTRODUCTION Amino acids production has been the second most important in quantity within “white biotechnology” after antibiotics production which is taking the lead (Shyamkumar et al., 2014). Since the 1950s, the fermentation method of amino acid production has become a vital technology in the area of industrial microbiology (Abou-taleb, 2014; Paloyan et al., 2022). Microorganisms involved in amino acid fermentation are found not to excrete amino acid in reasonable amounts due to the regulatory mechanism. Therefore, to produce a surplus of these amino acids, there is need to generate mutants that have the capacity of overproducing the respective amino acids. Mutagenesis occurs when there is a change in the metabolic process and thus has become the most extensively used tool for industrial microorganisms. Mutations can be produced chemically or by exposing the microorganisms to irradiation. Microorganisms used in the fermentation of amino acids can be categorized into 4 groups, namely, the wild-type, auxotrophic mutant, regulatory mutant, and auxotrophic regulatory mutant (Zelder et al., 2005). Auxotrophic mutant which is found to be resistant to analogues is widely employed in large scale fermentation of amino acids. Hopwood (1970) reported the use of penicillin enrichment for auxotrophic mutants’ isolation and which can also be employed to modify a particular auxotrophic isolate. Lopez et al. (1997) defined immobilization as the process by which particles are attached or entrapped, which is basically applied to all types of biocatalysts including, cellular organelles, enzymes, and plant and animal cells. Immobilization of cells is one of the methods employed in the field of biotechnology to improve amino acid production (Amin et al., 2010). Microbial cell immobilization is found useful in the field