Gordonia sp. SoCg alkB gene confers the ability to degrade and use n-alkanes as carbon source in Gram positive bacteria

Abstract

Gordonia sp. SoCg, a Gram positive strain able to grow on long chain n-alkanes1, possess a single copy of alkB2 gene, whose product is required for n-alkane hydroxylation3. An analysis of alkB flanking regions revealed five ORFs which were designed as orf1, rubA3, rubA4, rubB and alkU, according to the sequence 14 homology with that of known alk clusters3. In G. sp. SoCg the transcription of these genes was induced by long-chain and solid n-alkanes as revealed by quantitative RT-PCR, and the essential role of alkB in nalkane degradation was demonstrated by the construction of an alkB disruption mutant strain3. The SoCg alkB gene was successfully expressed in Streptomyces coelicolor M145 (M145-AH), and the production of 1-hexadecanol from n-hexadecane oxidation was observed3. A differential study of global gene expression of M145-AH cultures was performed, where n-hexadecane (C16) glucose (GLU) and none (NC) were provided as only carbon source, respectively. Proteomic analysis, based on 2D-DIGE and MS procedures, revealed a gradual metabolic adaptation to n-hexadecane utilization, not dissimilar from that one revealed in specialized alkane-degraders4. In addition, expression profiles of central carbon metabolism enzymes revealed that the addition of a single gene confers the ability to use recalcitrant pollutants as simple sugars in Streptomyces. Altogether these data, expanding the knowledge on n-alkane bioconversion mechanisms in Gram positive bacteria, could provide new technological platforms for bioremediation studies and strategies. Quatrini, P., Scaglione, G., De Pasquale, C., Riela, S., & Puglia, A. M. (2008). Isolation of gram-positive n-alkane degraders from a hydrocarbon- contaminated mediterranean shoreline. Journal of Applied Microbiology, 104(1), 251-259. Lo Piccolo, L., De Pasquale, C., Fodale, R., Puglia, A. M. & Quatrini, P. . An alkane hydroxylase system of Gordonia sp. Strain SoCg is involved in degradation of solid n-alkanes. Applied and Environmental Microbiology. In revision. van Beilen, J. B., & Funhoff, E. G. (2007). Alkane hydroxylases involved in microbial alkane degradation. Applied Microbiology and Biotechnology, 74(1), 13-21. Sabirova, J. S., Ferrer, M., Regenhardt, D., Timmis, K. N., & Golyshin, P. N. (2006). Proteomic insights into metabolic adaptations in Alcanivorax borkumensis induced by alkane utilization. Journal of Bacteriology, 188(11), 3763-3773.