Involvement of an Alkane Hydroxylase System of Gordonia sp. Strain SoCg in Degradation of Solid n -Alkanes

Abstract

Enzymes involved in oxidation of long-chain n-alkanes are still not well known, especially those in Grampositive bacteria. This work describes the alkane degradation system of the n-alkane degrader actinobacterium Gordonia sp. strain SoCg, which is able to grow on n-alkanes from dodecane (C 12 ) to hexatriacontane (C 36 ) as the sole C source. SoCg harbors in its chromosome a single alk locus carrying six open reading frames (ORFs), which shows 78 to 79% identity with the alkane hydroxylase (AH)-encoding systems of other alkane-degrading actinobacteria. Quantitative reverse transcription-PCR showed that the genes encoding AlkB (alkane 1-monooxygenase), RubA3 (rubredoxin), RubA4 (rubredoxin), and RubB (rubredoxin reductase) were induced by both n-hexadecane and n-triacontane, which were chosen as representative long-chain liquid and solid n-alkane molecules, respectively. Biotransformation of n-hexadecane into the corresponding 1-hexadecanol was detected by solid-phase microextraction coupled with gas chromatography-mass spectrometry (SPME/GC-MS) analysis. The Gordonia SoCg alkB was heterologously expressed in Escherichia coli BL21 and in Streptomyces coelicolor M145, and both hosts acquired the ability to transform n-hexadecane into 1-hexadecanol, but the corresponding long-chain alcohol was never detected on n-triacontane. However, the recombinant S. coelicolor M145-AH, expressing the Gordonia alkB gene, was able to grow on n-triacontane as the sole C source. A SoCg alkB disruption mutant that is completely unable to grow on n-triacontane was obtained, demonstrating the role of an AlkB-type AH system in degradation of solid n-alkanes.

Two Novel Alkane Hydroxylase-Rubredoxin Fusion Genes Isolated from a Dietzia Bacterium and the Functions of Fused Rubredoxin Domains in Long-Chain n -Alkane Degradation

“…The AlkB-type alkane hydroxylase system of Gordonia sp. strain SoCg has been also reported to be involved in the degradation of solid n-alkanes, although the hydroxylation activities of solid n-alkanes have not been detected (19). Recently, a novel AlkB-Rd fusion alkane hydroxylase was found in Dietzia sp.…”

Cofactor engineering for advancing chemical biotechnology

“…Expression of a similar P450 in E. coli from a tricistronic construct generated a whole cell biocatalyst that efficiently oxidized (1R)-(+)-camphor to 5-exo-hydroxycamphor and limonene to (-)-perillyl alcohol [10]. Gordonia SoCg alkB (alkane 1-monooxygenase) was expressed in E. coli BL21 and in Streptomyces coelicolor M145, and both hosts acquired the ability to transform n-hexadecane into 1-hexadecanol [62]. An E. coli system composed of P450pyr triple mutant, ferredoxin reductase, glucose dehydrogenase and ferredoxin genes, was engineered to show a high activity and high chiral efficiency in forming valuable pharmaceutical intermediates [11].…”

Biodegradation of Polyethylene by a Soil Bacterium and AlkB Cloned Recombinant Cell

“…They confirmed alkane hydroxylase protein expression by proteomics, and suggested the strain as an eligible tool for the bioremediation of oil contaminated soil. Piccolo et al [26] described the alkane degradation enzyme system of Gordonia sp. which can grow on C 12~ C 36 n-alkanes.…”