Perspective: what is known, and not known, about the connections between alkane oxidation and metal uptake in alkanotrophs in the marine environment

Abstract

Article Summary Should iron and copper be added to the environment to stimulate the natural bioremediation of marine oil spills? The key enzymes that catalyze the oxidation of alkanes require either iron or copper, and the concentration of these ions in seawater is vanishingly low. Nevertheless, the dependence of alkane oxidation activity on external metal concentrations remains unclear. This perspective will summarize what is known about the co-regulation of alkane oxidation and metal acquisition and pose a series of critical questions to which, for the most part, we do not yet have answers. The paucity of answers points to the need for additional studies to illuminate the cellular biology connecting microbial growth on alkanes to the acquisition of metal ions.

Biopolymers made from methane in bioreactors

“…A total of 5 μM of copper and iron was spiked on day 5 and monitored until day 10 (Table ). Both copper and iron have been reported to regulate/improve pMMO and sMMO activities in methanotrophs thereby improving CH 4 removal . As expected MOCs for the CB‐CSTR increased by ∼72% following trace metal addition, while only a ∼3% increase was recorded for the LB‐CSTR (Table ).…”

“…Type II methanotrophs generally rely on particulate methane monooxygenase (pMMO) and soluble methane monooxygenase (sMMO) for converting CH 4 to methanol in the first step of oxidation, which is a critical, highly energy intensive step in the process [7,35]. These two enzymes contain copper and iron centers, respectively, and it should therefore be possible to upregulate their expression/activity through adequate provision of these two trace elements [43][44][45][46].…”

Bacterial Diversity Associated with the Coccolithophorid AlgaeEmiliania huxleyiandCoccolithus pelagicusf.braarudii

“…First, we believe that it is important to understand their ecological relationship to algae in the marine environment and then to use this knowledge to try improving natural oil spill bioremediation: for example, will there be better natural bioremediation of oil spills in regions that are dominated by primary production? Or is the use of iron fertilization during oil spill events beneficial in stimulating both primary production and the associated bacterial community that clearly comprises many key hydrocarbonoclastic bacteria such as Alcanivorax , as well as ensuring a sufficient supply of iron for the iron-requiring alkane hydroxylases of all oil-degrading bacteria [ 61 ]? Second, specific genes and activities of oil-degraders can potentially be exploited for biosurfactant, bioemulsifier [ 62 , 63 ], or polyhydroxyalkanoate production [ 64 ], or the potential development of alkane hydroxylases to catalyze difficult-to-synthesize molecules [ 65 ].…”