In vivo Toxicopathological Evaluation of a Purified Bioflocculant Produced by Arthrobacter humicola

Introduction: In spite of the commendable flocculating activities of microbial flocculants, a good number of them potentiate significant toxicity. This study evaluated the in vivo toxicological implications of treatment with the Purified bioflocculant (PB) from Arthrobacter humicola using OECD guidelines. Materials and Methods: In the acute toxicity assessment, a single oral administration of 2000 mg/kg body weight (b.w.) of PB was given to the Wistar rats and the animals were observed for 2 weeks. The daily dose toxicity testing was performed through daily oral treatment with graded doses (50, 200 and 500 mg/kg b.w.) of PB for 4 weeks. Clinical signs of toxicity, behavioral changes, hematological and biochemical parameters were thereafter evaluated. Results: PB at 2000 mg/kg b.w. produced no treatment-mediated signs of toxicity, behavioral changes or mortality in the animals. Thus, its no-observed-adverse-effect level was estimated to be above 2000 mg/kg b.w. In the repeated dose toxicity testing, treatments with PB also revealed no significant differences in the feeding patterns, lipid profiles, hematological and clinical biochemistry parameters when compared with the control group. Although, at 500 mg/kg b.w. PB, a significant increase was observed in the serum activities of alkaline phosphatase, nonetheless, cage side observations recorded no treatment-induced signs of toxicity and macro-histopathological examinations of all the investigated organs also revealed no obvious morphological changes. Conclusion: The overall results suggested that PB was well tolerated by the animals and is endowed with monosaccharides bearing functional groups of flocculation importance, thus, suggesting its potential application as a safe actinomycetes bioflocculant for water treatment.