Metabolic and stress responses of Acinetobacter oleivorans DR1 during long‐chain alkane degradation. Issue 6 (31st August 2017)

• Record Type: Journal Article
• Authors: Park, Chulwoo; Shin, Bora; Jung, Jaejoon; Lee, Yunho; Park, Woojun
• Other Names: Averous Luc guestEditor.; Blank Lars M. guestEditor.; O'Connor Kevin guestEditor.; Diaz Eduardo guestEditor.; Prieto Auxi guestEditor.; Wierckx Nick guestEditor.; Zimmermann Wolfgang guestEditor.
• Is Part Of: Microbial biotechnology. Volume 10:Issue 6(2017:Nov.)
• Page Start: 1809
• Page End: 1823
• Publication Date: 2017-08-31
• Subjects: Microbial biotechnology -- Periodicals; Biotechnology; Microbiology; 660.62
• DOI: 10.1111/1751-7915.12852
• Languages: English
• ISSNs: 1751-7915

Abstract

Summary: Acinetobacter oleivorans DR1 can utilize C12 –C30 alkanes as a sole carbon source but not short‐chain alkanes (C6, C10 ). Two copies of each alkB ‐, almA ‐ and ladA ‐type alkane hydroxylase (AH) are present in the genome of DR1 cells. Expression and mutational analyses of AHs showed that alkB1 and alkB2 are the major AH‐encoding genes under C12 –C30, and the roles of other almA ‐ and ladA genes are negligible. Our data suggested that AlkB1 is responsible for long‐chain alkane utilization (C24 –C26 ), and AlkB2 is important for medium‐chain alkane (C12 –C16 ) metabolism. Phylogenetic analyses revealed large incongruities between phylogenies of 16S rRNA and each AH gene, which implies that A. oleivorans DR1 has acquired multiple alkane hydroxylases through horizontal gene transfer. Transcriptomic and qRT‐PCR analyses suggested that genes participating in the synthesis of siderophore, trehalose and poly 3‐hydroxybutyrate (PHB) were expressed at much higher levels when cells used C30 than when used succinate as a carbon source. The following biochemical assays supported our gene expression analyses: (i) quantification of siderophore, (ii) measurement of trehalose and (iii) observation of PHB storage. Interestingly, highly induced both ackA gene encoding an acetate kinase A and pta gene encoding a phosphotransacetylase suggested unusual ATP synthesis during C30 alkane degradation, which was demonstrated by ATP measurement using the ΔackA mutant. Impaired growth of the ΔaceA mutant indicated that the glyoxylate shunt pathway is important when C30 alkane is utilized. Our data provide insight into long‐chain alkane degradation in soil microorganisms. Abstract : Expression and mutational analyses of alkane hydroxylases (AHs) showed that alkB1 and alkB2 are the major AH‐encoding genes under C12‐C30, and the roles of other almA‐ and ladA genes are negligible in Acinetobacter oleivorans DR1. A. oleivorans DR1 has acquired multiple AHs through horizontal gene transfer. Transcriptomic, qRT‐PCR, mutational analyses suggested that genes participating in the synthesis of siderophore, trehalose, poly 3‐hydroxybutyrate (PHB), glyoxylate bypass are important for utilization of long chain alkanes.