# Bioremediation of Crude Oil by _Corynebacterium stationis_ CsPe-1: A Preliminary In Vitro Study
## 1 Introduction
It can also use polycyclic aromatic hydrocarbons as its sole source of carbon and energy [29], and is capable of degrading petroleum either alone or in consortium with other bacteria [11,30,31], as it produces various enzymes for degrading keratin, atrazine, trichloroethylene, and dichlordiphenyltrichloroethane (DDT), and even acts in the bioremediation of metals [32]. _Corynebacterium stationis_ is a Gram-positive, rod-shaped bacterium, 0.6-1 mm in diameter, without spores, occurring as single cells, in pairs or in clusters, and also in angular, V-shaped, or occasionally palisaded arrangements. They are facultative anaerbes, but develop best under aerobic conditions [33,34]. These bacteria can be isolated from a variety of environments including animal skin and mucous membranes, foliage, soil, some dairy products, fresh water, salt water, and sewage. Bacteria from soil are considered GRAS (generally recognized as safe) organisms, have genetic stability so they do not mutate easily, and can withstand changes in environmental factors such as pH, osmotic pressure, and temperature [35]. _Corynebacterium_ species are lipophilic, and can assimilate carbon from various sources and have the ability to produce biosurfactants, which allows them to degrade oils and hydrocarbons and grow efficiently, so they have the potential to be used in the in situ bioremediation of environments contaminated with petroleum or petroleum hydrocarbons [36; 37; 38]. Studies have been conducted using these free and immobilized bacteria and it has been observed that when the free bacteria are used, 71.9% degradation of total petroleum hydrocarbons (TPH) is obtained, while when the bacteria are immobilized on a support with biocarbon, 78.9% degradation is obtained [38]. Some _Corynebacterium_ species also have the ability to degrade a wide range of aromatic compounds, including inorganic species of arsenic (As), a toxic metalloid that is ubiquitously found in nature and has caused serious health problems worldwide. Corynebbacterium is one of the most arsenic-resistant bacteria and has been investigated and enhanced by metabolic engineering to be used as an efficient bio-tool for bio-bioaccumulation of arsenic and for the sequestration of metals such as cadmium (Cd) and lead (Pb) [35]. Genomic techniques, such as 16s rDNA sequencing, are important for the study of species with bioremediation potential, as they can identify possible genes involved in the translation of enzymes responsible for hydrocarbon degradation [39], such as alkane monooxygenase \(\mathit{LadAB}\) genes [40]. On the other hand, when applying in situ bioremediation techniques to oil-contaminated soils, it is important to control the proportion and ratio of native species, soil conditioning, and the introduction of oil-degrading strains [41]. Petroleum is a persistent pollutant with significant adverse effects on ecosystems and human health. Conventional physical-chemical remediation methods are costly and often cause collateral environmental damage. In this context, the use of _C. stationis_ for the bioremediation of hydrocarbons has emerged as a sustainable and cost-effective strategy, with the additional advantage of eliminating the generation of additional toxic waste. This approach has potential for future studies on a larger scale or under real conditions. The present study therefore sought to evaluate the impact of two inoculum concentrations on crude oil degradation by the Peruvian strain _C. stationis_ CsPe-1. The use of native strains is particularly promising for the bioremediation of oil-contaminated environments, since these strains show adaptability to the environmental conditions of their origin. It is noteworthy that this research is aligned with Sustainable Development Goals (SDGs) 14 (Life Below Water) and 15 (Life on Land), underscoring its significance for global sustainability initiatives.