Biodegradation of 4-nitroaniline by plant-growth promoting Acinetobacter sp. AVLB2 and toxicological analysis of its biodegradation metabolites.
4-nitroaniline (4-NA) is one of the major priority pollutants generated from industrial productions and pesticide transformation; however very limited biodegradation details have been reported. This work is the first to report 4-NA biodegradation kinetics and toxicity reduction using a newly isolated plant-growth promoting bacterium, Acinetobacter sp. AVLB2. The 4-NA-dependent growth kinetics parameters: μmax, Ks and Ki, were determined to be 0.039 h(-1), 6.623 mg L(-1) and 25.57 mg L(-1), respectively using Haldane inhibition model, while the maximum biodegradation rate (Vmax) of 4-NA was at 0.541 mg L(-1) h(-1) and 0.551 mg L(-1) h(-1), following Michaelis-Menten and Hanes-Woolf models, respectively. Biodegradation pathway of 4-NA by Acinetobacter sp. AVLB2 was proposed, and successfully led to the reduction of 4-NA toxicity according to the following toxicity assessments: microbial toxicity using Escherichia coli DH5α, phytotoxicity with Vigna radiata and Crotalaria juncea, and cytogenotoxicity with Allium cepa root-tip cells. In addition, Acinetobacter sp. AVLB2 possess important plant-growth promoting traits, both in the presence and absence of 4-NA. This study has provided a new insight into 4-NA biodegradation ability and concurrent plant-growth promoting activities of Acinetobacter sp. AVLB2, which may indicate its potential role for rhizoremediation, while sustaining crop production even under 4-NA stressed environment.
Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
Sivagnanam
S
Silambarasan
Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; Center of Excellence on Hazardous Substance Management (HSM), Chulalongkorn University, Bangkok 10330, Thailand. Electronic address: alisa.v@chula.ac.th.
Alisa S
AS
Vangnai
D000150:Acinetobacter / Q000302:isolation & purification / Q000378:metabolism*; D000814:Aniline Compounds / Q000378:metabolism*; D001673:Biodegradation, Environmental; D007887:Fabaceae / Q000382:microbiology; D018675:Toxicity Tests
D000814:Aniline Compounds; C019498:4-nitroaniline
4-Nitroaniline; Acinetobacter sp. AVLB2; Biodegradation pathway; Kinetic analysis; Plant growth promotion