Differential protein expression during growth on linear versus branched alkanes in the obligate marine hydrocarbon‐degrading bacterium Alcanivorax borkumensis SK2T

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

A through-life costing methodology for use in product-service-systems

Availability-based contracts which provide customers with the use of assets such as machines, ships, aircraft platforms or subsystems like engines and avionics are increasingly offered as an alternative to the purchase of an asset and separate support contracts. The cost of servicing a durable product can be addressed by Through-life Costing (TLC). Providers of advanced services are now concerned with the cost of delivering outcomes that meet customer requirements using combinations of assets and activities via a Product Service System (PSS). This paper addresses the question: To what extent are the current approaches to TLC methodologically appropriate for costing the provision of advanced services, particularly availability, through a PSS? A novel methodology for TLC is outlined addressing the challenges of PSS cost assessment with regard to 'what?' (cost object), 'why/to what extent?' (scope and boundaries), and 'how?' (computations). The research provides clarity for those seeking to cost availability in a performance-orientated contractual setting and provides insight to the measures that may be associated with it. In particular, a reductionist approach that focuses on one cost object at a time is not appropriate for a PSS. Costing an advanced service delivered through a PSS is a problem of attributing the value of means to the economic activities carried out for specific ends to be achieved. Cost results from the interplay between monetary and non-monetary metrics, and uncertainties thereof. Whilst seeking to ensure generality of the findings, the application of TLC examined here is limited to a military aircraft platform and subsystems. © 2014 Elsevier B.V. All rights reserved