Differential protein expression during growth on linear versus branched alkanes in the obligate marine hydrocarbon‐degrading bacterium Alcanivorax borkumensis SK2^T

Abstract

Summary Alcanivorax borkumensis SK2T is an important obligate hydrocarbonoclastic bacterium (OHCB) that can dominate microbial communities following marine oil spills. It possesses the ability to degrade branched alkanes which provides it a competitive advantage over many other marine alkane degraders that can only degrade linear alkanes. We used LC–MS/MS shotgun proteomics to identify proteins involved in aerobic alkane degradation during growth on linear (n‐C14) or branched (pristane) alkanes. During growth on n‐C14, A. borkumensis expressed a complete pathway for the terminal oxidation of n‐alkanes to their corresponding acyl‐CoA derivatives including AlkB and AlmA, two CYP153 cytochrome P450s, an alcohol dehydrogenase and an aldehyde dehydrogenase. In contrast, during growth on pristane, an alternative alkane degradation pathway was expressed including a different cytochrome P450, an alcohol oxidase and an alcohol dehydrogenase. A. borkumensis also expressed a different set of enzymes for β‐oxidation of the resultant fatty acids depending on the growth substrate utilized. This study significantly enhances our understanding of the fundamental physiology of A. borkumensis SK2T by identifying the key enzymes expressed and involved in terminal oxidation of both linear and branched alkanes. It has also highlights the differential expression of sets of β‐oxidation proteins to overcome steric hinderance from branched substrates.

Comparative Proteomics of Marinobacter sp. TT1 Reveals Corexit Impacts on Hydrocarbon Metabolism, Chemotactic Motility, and Biofilm Formation

“…The n -hexadecane metabolism of Marinobacter sp. TT1 appears relatively analogous to the alkane metabolism of other marine alkane degraders [ 49 , 50 , 51 ], with our results suggesting important roles for the AupAB, AlkB2, and cytochrome P450 homologues and a number of involved dehydrogenases. The AupA homologue likely enables strain TT1 to take up n -hexadecane from the outer membrane, with the AupB homologue guiding the alkane to the inner membrane, where the terminal oxidation machinery is located [ 46 ].…”

Beyond oil degradation: enzymatic potential of Alcanivorax to degrade natural and synthetic polyesters

“…Because its isolation and characterization, the genus Alcanivorax has become a reference of marine oildegradation (Yakimov et al, 1998;de Lorenzo, 2006;Schneiker et al, 2006;Gregson et al, 2019). Although Alcanivorax spp.…”

Bacterial Community Legacy Effects Following the Agia Zoni II Oil-Spill, Greece

“…Previous studies of oil-contaminated sediment ( Coulon et al, 2012 ) and seawater ( Teramoto et al, 2013 ) observed Oleibacter and Alcanivorax in similar abundances, in line with our observations. However, in seawater-based laboratory experiments Thalassolituus has been observed to outcompete other alkane-degraders such as Alcanivorax ( McKew et al, 2007 ), through its use of medium- and long-chained alkanes ( Gregson et al, 2019 ); this was not observed in the sediment samples collected from the Agia Zoni II oil-spill, whereby Alcanivorax was in greater abundance.…”

“…Alternatively, this persistence could be due to the low levels of branched alkanes, such as pristane and phytane, observed within the sediments in the months following September. Unlike most OHCB, certain species of Alcanivorax can use branched alkanes, for example, A. borkumensis SK2T (Yakimov et al, 1998;Gregson et al, 2019), A. dieselolei B-5 (Liu et al, 2011), and A. hongdengensis A-11-3 (Wang and Shao, 2012).…”