Utilization of n-alkanes by a newly isolated strain of Acinetobacter venetianus: the role of two AlkB-type alkane hydroxylases.
A bacterial strain capable of utilizing n-alkanes with chain lengths ranging from decane (C10H22) to tetracontane (C40H82) as a sole carbon source was isolated using a system for screening microorganisms able to grow on paraffin (mixed long-chain n-alkanes). The isolate, identified according to its 16S rRNA sequence as Acinetobacter venetianus, was designated A. venetianus 6A2. Two DNA fragments encoding parts of AlkB-type alkane hydroxylase homologues, designated alkMa and alkMb, were polymerase chain reaction-amplified from the genome of A. venetianus 6A2. To study the roles of these two alkM paralogues in n-alkane utilization in A. venetianus 6A2, we constructed alkMa, alkMb, and alkMa/alkMb disruption mutants. Studies on the growth patterns of the disruption mutants using n-alkanes with different chain lengths as sole carbon source demonstrated central roles for the alkMa and alkMb genes in utilization of C10 to C18 n-alkanes. Comparative analysis of these patterns also suggested different substrate preferences for AlkMa and AlkMb in n-alkane utilization. Because both single and double mutants were able to grow on n-alkanes with chain lengths of C20 and longer, we concluded that yet another enzyme(s) for the utilization of these n-alkanes must exist in A. venetianus 6A2.
Throne-Holst
Mimmi
M
Department of Biotechnology, NTNU, 7491, Trondheim, Norway. Mimmi.Throne-Holst@biotech.ntnu.no
Markussen
Sidsel
S
Winnberg
Asgeir
A
Ellingsen
Trond E
TE
Kotlar
Hans-Kristian
HK
Zotchev
Sergey B
SB
D000150:Acinetobacter / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000473:Alkanes / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D042926:Cytochrome P-450 CYP4A / Q000235:genetics / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010232:Paraffin / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013379:Substrate Specificity
D000473:Alkanes; D001426:Bacterial Proteins; D007527:Isoenzymes; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D010232:Paraffin; D042926:Cytochrome P-450 CYP4A