Two new nontoxic, non-pathogenic strains of Sphingomonas elodea for gellan gum production

• Two new Sphingomonas elodea strains (PHP1 and PBAD1) were developed for gellan production.
• Nonpathogenic and nontoxic S. elodea strains must be used to produce gellan.
• Studies were conducted to determine whether PHP1 and PBAD1 meet this requirement.
• Results show that neither PHP1 nor PBAD1 are pathogenic or toxic.

Two new strains of Sphingomonas elodea (designated as PHP1 and PBAD1) were tested for toxicity and pathogenicity in healthy Sprague-Dawley CD® IGS rats in separate studies. In each study, twelve rats/sex were administered ≥108 viable cells/rat by oral gavage, and four untreated rats/sex served as controls. Blood, feces, and selected organs/tissues collected at various times over the course of the 22 day study were evaluated for the presence of PHP1 or PBAD1 (depending on the study) by a validated method, to determine the potential for survival, propagation, or infectivity of PHP1 and PBAD1 cells in the rat. No mortalities, test substance-related changes in clinical or macroscopic findings, body weight or body weight gain were observed in treated animals compared with controls, indicating a lack of toxicity. PHP1 or PBAD1 were not detected in the tissue, fecal or fluid samples collected from treated animals. Therefore, neither PHP1 nor PBAD1 were pathogenic or acutely toxic under the conditions of the studies.