Characterization of a Novel Microbial Source of L-Glutaminase Production by Bacillus zanthoxyli Jaberi, Isolated from Saline Soil in Shushtar City, Iran

Abstract

Halophilic bacteria represent valuable sources of enzymes with exceptional stability under extreme conditions, making them promising candidates for industrial and therapeutic applications. This study aimed to isolate and characterize halophilic bacterial strains producing L-glutaminase, L-asparaginase, and L-methioninase from saline soils in Shushtar, Iran. Forty-four bacterial isolates were obtained through enrichment and selective culture techniques. Screening for extracellular L-glutaminase, L-asparaginase, and L-methioninase production was performed using phenol red-based plate assays, followed by quantitative enzyme activity determination via the Nesslerization method. Enzyme activities were assessed under varying pH and temperature conditions. Two isolates exhibited significant activity: Bacillus subtilis Iran2024 produced L-asparaginase (3.55 ± 0.12 U/mL) and L-glutaminase (4.62 ± 0.18 U/mL), while Bacillus zanthoxyli Jaberi.Iran produced L-glutaminase (5.85 ± 0.21 U/mL). Optimal activity for both enzymes occurred at 40 °C and pH 8. Notably, this study reports for the first time the production of L-glutaminase by Bacillus zanthoxyli. The high stability and catalytic efficiency of these halophilic enzymes highlight their potential for biotechnological and therapeutic applications, particularly in enzyme-based cancer therapy.

Keywords: Halophilic bacteria, Bacillus zanthoxyli, Bacillus subtilis, L-glutaminase, L-asparaginase