title: Growth of Rhodococcus sp. strain BCP1 on gaseous n-alkanes: new metabolic insights and transcriptional analysis of two soluble di-iron monooxygenase genes.
abstract: Rhodococcus sp. strain BCP1 was initially isolated for its ability to grow on gaseous n-alkanes, which act as inducers for the co-metabolic degradation of low-chlorinated compounds. Here, both molecular and metabolic features of BCP1 cells grown on gaseous and short-chain n-alkanes (up to n-heptane) were examined in detail. We show that propane metabolism generated terminal and sub-terminal oxidation products such as 1- and 2-propanol, whereas 1-butanol was the only terminal oxidation product detected from n-butane metabolism. Two gene clusters, prmABCD and smoABCD-coding for Soluble Di-Iron Monooxgenases (SDIMOs) involved in gaseous n-alkanes oxidation-were detected in the BCP1 genome. By means of Reverse Transcriptase-quantitative PCR (RT-qPCR) analysis, a set of substrates inducing the expression of the sdimo genes in BCP1 were assessed as well as their transcriptional repression in the presence of sugars, organic acids, or during the cell growth on rich medium (Luria-Bertani broth). The transcriptional start sites of both the sdimo gene clusters were identified by means of primer extension experiments. Finally, proteomic studies revealed changes in the protein pattern induced by growth on gaseous- (n-butane) and/or liquid (n-hexane) short-chain n-alkanes as compared to growth on succinate. Among the differently expressed protein spots, two chaperonins and an isocytrate lyase were identified along with oxidoreductases involved in oxidation reactions downstream of the initial monooxygenase reaction step.
authors.affiliation: Department of Pharmacy and Biotechnology, University of Bologna Bologna, Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Cappelletti
authors.affiliation: Department of Pharmacy and Biotechnology, University of Bologna Bologna, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Presentato
authors.affiliation: Department of Pharmacy and Biotechnology, University of Bologna Bologna, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Milazzo
authors.affiliation: Department of Biological Sciences, University of Calgary Calgary, Alberta, Canada.
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Turner
authors.affiliation: Department of Pharmacy and Biotechnology, University of Bologna Bologna, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Fedi
authors.affiliation: Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna Bologna, Italy.
authors.forename: Dario
authors.initials: D
authors.lastname: Frascari
authors.affiliation: Department of Pharmacy and Biotechnology, University of Bologna Bologna, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Zannoni
keywords: Rhodococcus sp. strain BCP1; gaseous n-alkanes; monooxygenase gene expression; propane and n-butane oxidation; soluble di-iron monooxygenase