Biodegradation of used engine oil by novel strains of Ochrobactrum anthropi HM-1 and Citrobacter freundii HM-2 isolated from oil-contaminated soilReportar como inadecuado




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3 Biotech

, 6:226

First Online: 19 October 2016Received: 05 June 2016Accepted: 03 October 2016

Abstract

Used engine oil UEO constitutes a serious environmental problem due to the difficulty of disposal off or reuse. Ten bacterial strains with biodegradation potential were isolated from UEO-contaminated soil sample using enrichment technique. Two strains which exhibited the highest degradation %, 51 ± 1.2 and 48 ± 1.5, respectively, were selected. Based on the morphological, biochemical characteristics and 16S rRNA sequence analysis, they were identified as Ochrobactrum anthropi HM-1 accession no: KR360745 and Citrobacter freundii HM-2 accession no: KR360746. The different conditions which may influence their biodegradation activity, including UEO concentration 1–6 %, v-v, inoculum size 0.5–4 %, v-v, initial pH 6–8, incubation temperature 25–45 °C, and rotation speed 0–200 rpm, were evaluated. The optimum conditions were found to be 2 % UEO, 2 % inoculum size, pH 7.5, incubation temperature 37 °C, and 150 rpm. Under the optimized conditions, strains HM-1, HM-2, and their mixture efficiently degraded UEO, they achieved 65 ± 2.2, 58 ± 2.1, and 80 ± 1.9 %, respectively, after 21 days of incubation. Biodegradation of UEO was confirmed by employing gas chromatography analysis. Gamma radiation 1.5 kGy enhanced the degradation efficiency of irradiated bacterial mixture 95 ± 2.1 % as compared to non-irradiated 79 ± 1.6 %. Therefore, strains HM-1 and HM-2 can be employed to develop a cost-effective method for bioremediation of used engine-oil-polluted soil.

KeywordsUsed engine oil Biodegradation Ochrobactrum anthropi Citrobacter freundii  Download fulltext PDF



Autor: Haytham M. M. Ibrahim

Fuente: https://link.springer.com/







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