Actinomycetes <i>Rhodococcus ruber</i> – Key and Universal Bioxidizers of Gaseous Alkanes C₂−C₄

In recent years, there has been an increasing interest of researchers in microorganisms capable of oxidizing higher gaseous homologues of methane (ethane, propane, n-butane). Among propane- and butane-oxidizing bacteria, representatives of Rhodococcus ruber attract special attention; they can easily adapt to extreme environmental conditions and have significant potential for biotechnology. The review emphasizes the importance of R. ruber as a bioindicator of oil and gas fields and a component of microbial consortia for the degradation of hydrocarbons and other xenobiotics. Data on natural substrates and ecological niches of gas-oxidizing Rhodococcus are presented, their morphological and physiological features are described. Their role in biogeochemical cycles and the potential for industrial use are discussed. As a result of the analysis of functional genes and enzyme systems of gaseous hydrocarbon (C2−C4) catabolism, the key stages of propane oxidation in Rhodococcus were identified and the role of propanotrophy in the bioremediation potential of R. ruber was revealed. The need for further research to understand the mechanisms of adaptation of these microorganisms to anthropogenic impact was substantiated.