Monooxygenases involved in the n-alkanes metabolism by Rhodococcus sp. BCP1: molecular characterization and expression of alkB gene

Abstract

Discussion 107 Summary 113Chapter 5 -Analysis of the alkB gene expression Summary 157Chapter 6 -Proteomic analysis of n-alkanes growth of Rhodococcus sp. BCP1 Chapter 1 -General Introduction PrefaceThe quality of life on Earth is tightly related with the overall quality of the environment [1]. During the last century it was commonly believed that the abundance of land and resources were unlimited and it was rarely acknowledged that the production, use, and disposal of hazardous substances had environmental and health effects [1][2][3]. Owing to this, human activity has deliberately or inadvertently released into waters and soil a variety of toxic compounds as refrigerants, paints, solvents, herbicides and pesticides that can cause considerable environmental pollution and human health problems as a result of their persistence, toxicity, and transformation into hazardous metabolites [4,5]. Very soon, however, it became clear how the carelessness and negligence in handling the industrial wastes and gas emissions had caused dramatic effect on the nature and on human health [1].Nowadays, the concern about the global warming and the climate changing induced the government regulatory agencies to establish procedures for assessing the environmental impact and health hazards of chemicals and for controlling/limiting their utilization.International efforts have been applied to remedy many contaminated sites all over the world, either as a response to the risk of adverse health or environmental effects caused by contamination or to enable the site to be redeveloped for use [5]. In response to public and government concern and because of the intriguing research problems presented, environmental scientists, biologists and chemists have been giving increased attention to identifying and determining the behavior and fate of organic compounds in natural ecosystems [5].Bioremediation procedures offer an economical and effective possibility to degrade or render innocuous toxic pollutants using natural biological activity [1]. By definition, bioremediation implies the use of living organisms, primarily microorganisms, to degrade the Since contaminant compounds are transformed by living organisms through reactions that take place as a part of their metabolic processes, environmental biotechnology focuses on the development of techniques to optimize environmental parameters to allow these metabolic pathways to proceed faster and, therefore, to improve the bio-degradation [1]. As a result, the removal of the contaminated soil can be necessary to let the biodegradation proceed in controlled sites (such as bioreactors). These ex situ approaches provide optimal conditions out one single step of the entire bio-degradation process. Hydrocarbons in the environmentHydrocarbons are energy-rich organic compounds consisting of carbon and hydrogen atoms and they can be saturated (only single C-H bounds) or unsaturated (one ore more double or triple C-H bounds). Alkanes are saturated hydrocarbons with the general formula C n H 2n+2 ; they can b...

The relative abundance of alkane‐degrading bacteria oscillated similarly to a sinusoidal curve in an artificial ecosystem model from oil‐well products

“…SoD and Rhodococcus sp. BCP1, which are responsible for the degradation of alkanes from C5 to C28, with C16–C20 alkanes as the most efficient substrates (Quatrini et al ., ; Amouric et al ., ; Cappelletti et al ., ; Song et al ., ). While the hydroxylases of the Dietzia alk B genotype and Rhodococcus alk B genotype prefer to catalyze the conversion of long‐chain alkanes (C16–C20), both Dietzia and Rhodococcus are aerobic, gram‐positive, nonsporulating, biosurfactant‐producing, metabolically versatile actinomycetes with hydrophobic outer membranes containing mycolic acids (De Carvalho et al ., ; Koerner et al ., ; Larkin et al ., ).…”

Systems biology and metabolic engineering of Rhodococcus for bioconversion and biosynthesis processes

“…In relation to this, Rhodococcus spp. strains are capable of performing biotransformation and biodegradation of many organic and xenobiotic compounds, such as hydrocarbons and chlorinated hydrocarbons, naphthenic acids, nitroaromatics, and pharmaceuticals (e.g., diclofenac and sulfamethoxazole) (Auffret et al 2009;Cappelletti et al 2010Cappelletti et al , 2015Cappelletti et al , 2016Cappelletti et al , 2018Orro et al 2015;Presentato et al 2018a, b, c;Weidhass et al 2009;Ivshina et al 2019;Tyumina et al 2019;Larcher and Yargeau 2011). Due to these wide metabolic capabilities and stress resistance/tolerance, Rhodococcus strains are considered ideal candidates for biotechnological applications in environmental remediation and pharmaceutical and chemical industries (Bell et al 1998;Busch et al 2019;Ceniceros et al 2017;Kis et al 2015;Larkin et al 2005;van der Geize andDijkhuizen 2004, Patek et al 2021).…”

“…While experimental works have mostly investigated culture conditions and suitable substrates for efficient biotechnological applications, the identification of specific genes/proteins involved in these biosynthetic pathways has been for a long time hindered by the lack of efficient molecular methods/tools generally applicable to Rhodococcus spp. strains (Cappelletti et al 2010). Transformation protocols in Rhodococcus spp.…”

Bacterial communities and their hydrocarbon bioremediation potential in the Bohai Sea, China

“…Community functions associated with the in situ bioremediation of petroleum-polluted environments have received extensive attention. The hydroxylases responsible for the first step of aerobic alkane degradation in prokaryotes belong to different families: short-chain alkane-oxidizing soluble non-heme diiron monooxygenases (SDIMO); heme (cytochrome P450) and non-heme (AlkB) medium-chain alkane (C5−C16) monooxygenases; and other long-chain alkane hydroxylases (Van Beilen et al 2006, Cappelletti 2009, Rojo 2009, Wang et al 2010, Nie et al 2014. AlkB and SDIMOs have been widely used to assess the diversity of oil-degraders and their oildegrading potential (Cappelletti 2009).…”

“…The hydroxylases responsible for the first step of aerobic alkane degradation in prokaryotes belong to different families: short-chain alkane-oxidizing soluble non-heme diiron monooxygenases (SDIMO); heme (cytochrome P450) and non-heme (AlkB) medium-chain alkane (C5−C16) monooxygenases; and other long-chain alkane hydroxylases (Van Beilen et al 2006, Cappelletti 2009, Rojo 2009, Wang et al 2010, Nie et al 2014. AlkB and SDIMOs have been widely used to assess the diversity of oil-degraders and their oildegrading potential (Cappelletti 2009). AlkB, as one of the key enzymes produced by aerobic alkanedegrading bacteria, was widely detected in α-, β-, and γ-Proteobacteria, as well as in Actinobacteria (Kuhn et al 2009, Nie et al 2014.…”