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Biokemistri
Nigerian Society for Experimental Biology
ISSN: 0795-8080
Vol. 25, No. 2, 2013, pp. 61-71
Bioline Code: bk13011
Full paper language: English
Document type: Research Article
Document available free of charge

Biokemistri, Vol. 25, No. 2, 2013, pp. 61-71

 en Effects of carbon source variation on microbial emulsification, haemolytic activity and secretion of extracellular macromolecules by Acinetobacter check for this species in other resources species
Igwo-Ezikpe, Miriam N.; Gbenle, George O.; Ilori, Matthew O.; Akintunde, Olumide; Udoh, Margaret U. & Komolafe, Damilola F.

Abstract

The recalcitrance and poor solubility of hydrocarbons have continually been merging challenges in bioremediation of polluted sites as such efforts have been directed into finding means to improve absorption of these compounds. The present study investigated the potential of Acinetobacter anitratus check for this species in other resources and Acinetobacter mallei check for this species in other resources to grow on and degrade varying concentration of chrysene and diesel oil respectively over a 7 day period. In addition, hydrocarbon emulsification, haemolytic activity and macromolecule secretion were also evaluated using the microbial extracellular culture media. Both isolates grew on the carbon sources in a concentration dependant manner. Residual chrysene obtained after degradation of 30, 50 and 100 mg/l respectively by A. anitratus were 0.02 ± 0.01, 2.15 ± 0.4 and 18.5 ± 0.7 mg/l while with A. mallei, they were 0.02 ± 0.03, 2.18 ± 0.6 and 29.5 ± 1.2 mg/l. Total hydrocarbon remaining after degradation of 3, 5, 15 and 30 % (v/v) diesel oil respectively using A. anitratus were 0.0 %, 0.0 %, 17.5 ± 0.9 % and 43.9 ± 1.1% whereas with A. mallei, they were 0.0 %, 2.1 ± 0.4%, 30.4 ± 0.5 % and 67.2 ± 1.4 % correspondingly. Extracellular fluid of both isolates from diesel oil growth media showed emulsification activities against kerosene, diesel oil, engine oil, hexadecane, dodecane and xylene at varying degree while no emulsification activity was observed when the isolates were grown on chrysene. Moreover, A. anitratus and A. mallei showed haemolytic activity when grown on diesel oil but not on chrysene. However, extracellular fluid from both chrysene and diesel oil growth media showed significant (P<0.05) difference in extracellular protein and carbohydrate concentration compared to non-carbon source growth media. Therefore, the significant (P<0.05) differences between both species of the Acinetobacter in terms of cell densities, bioemulsification, haemolysis and extracellular composition suggest that microbial biotransformation of pollutant may be dependent on microbial specie used, pollutant degraded and genetic make-up of isolate which determine macromolecules that are expressed.

Keywords
Acinetobacter; Bioremediation; Diesel oil; Hydrocarbons; Polycyclic aromatic hydrocarbon

 
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