# Bioremediation of Crude Oil by _Corynebacterium stationis_ CsPe-1: A Preliminary In Vitro Study
## 1 Introduction  
Currently, 80% of energy demand is met by fossil fuels, and this demand is expected to increase by 48% over the next 20 years [1]. Part of these fossil fuels are hydrocarbons, which are organic compounds with hydrogen and carbon in their chemical structure, forming various raw materials that are important energy sources for industry and are present in urban life as part of products such as petrol, solvents, and pains [2, 3, 4, 5]. Some hydrocarbons are found in nature and are chemical energy carriers, such as petroleum, which is a derivative of fossil fuels with a liquid consistency ranging from yellowish to black in color and is naturally formed in underground geological formations [3, 6]. Crude oil is composed of cycloalkanes (about 45%), alkanes (about 30%) and aromatic hydrocarbons (about 15%) [6]. Although petroleum hydrocarbons are important energy resources, they are the major source of organic pollutants, are highly toxic, and are in high demand, which has led to increased environmental pollution from exploration, production, maintenance, transport, storage, and accidental spills [7,8]. In the case of accidental oil spills, these hydrocarbons reach the groundwater through the mechanism of percolation through the soil and can also reach the oceans directly, negatively affecting the ecosystem and threatening the life that inhabits it [9, 10, 11]. Hydrocarbon compounds are also known to be carcinogenic and neurotoxic organic pollutants [12]. Unfortunately, petroleum hydrocarbons are difficult to degrade, so more attention has been paid to biodegradation methods that are part of bioremediation mechanisms, which is a promising technology and an alternative to physical and chemical methods that have become ineffective and costly in the removal of pollutants produced by anthropogenic activities and rapid industrialization [12, 13, 14]. On the other hand, the biodegradation of petroleum hydrocarbons is a technique that can be economical and environmentally friendly because it uses the same microbiota isolated from petroleum [15]. This microbiota is able to utilize oil as a carbon and energy source, making these microorganisms potential bioremediation agents for oil-contaminated environments [16]. On the other hand, studies to biodegradation oil from contaminated environments are in line with Sustainable Development Goals 14 and 15, Life Below Water and Life on Land, respectively. Hydrocarbon bioremediation studies involve a practice that promotes the preservation of ecosystems [17,18]. To date, 70 genera and 200 species of microorganisms capable of degrading oil have been reported, including bacteria, fungi and cyanobacteria, which are considered to be oleophilic microorganisms [15,19, 20, 21]. Among the bacteria, the genus _Bacillus_ stands out [22], as well as _Burkholderia_, _Mycobacterium_, _Polaromonas_, and _Pseudomonas_, which have been identified in oil-contaminated soils [18]. Fungi of the genera _Candida_, _Rhodotorula_, and _Aspergillus_ have shown potential for the biodegradation of petroleum hydrocarbons [23, 24, 25]. Moreover, fungal-bacterial consortia have been tested to improve oil biodegradation, such as the oil-degrading fungus _Sedosporium_ sp. ZYY and the surfactant-producing bacterium _Acinetobacter_ sp. Y2 [26]. All of these microorganisms can degrade petroleum hydrocarbons by producing hydrolase enzymes such as monooxygenases, dioxygenases, alkane hydroxylase, and catechol dioxygenase, which can degrade aromatic hydrocarbon alkanes to simpler computations that can then enter the tricarboxylic acid cycle [27]. It has also been reported that the Gram-negative bacterium _Stentrophonomas malophilia_ can survive in a wide range of environments and use many complex substances for its growth and development [28].