## 4 Discussion
Biofilm production also enables horizontal gene transfer, allowing the transfer of genetic material encoding for enzymes that are potent for the degradation of these hydrocarbon pollutants [53]. Thus, we sought out biosurfactant producers, which showed a reasonable amount of emulsification during the test. The emulsification layers for the three identified surfactant-producing microbes were between 1 and 1.5 cm. Strains of bacteria that produce biosurfactants can assist crude oil breakdown and increase PAH emulsification [54]. Mycobacteria that degrade PAHs exhibit a variety of physiological adaptations for survival in PAH-contaminated soils, including biofilm formation on PAH-containing surfaces or highly specific affinities for PAHs [55]. Numerous recognized biosurfactant producers are also microbes that degrade hydrocarbons [56; 57]. The impact of surfactants produced by microorganisms on bioremediation and improved oil recovery has been the subject of numerous studies in the last decade [58; 59]. Our hypothesis goes further and proposes that anaerobic bacteria present in water droplets may be trapped in bacterial biofilms at the water/oil interface within the soil, producing oxygen by reducing nitrates and perchlorates during anaerobic life cycles. This hypothesis is based on recent bacterial research [60; 61; 62]. Therefore, the biofilm would function as an oxygen sponge that may contain a lot or little oxygen. The aerobic consortium would then take over the degrading activity as the anaerobic activity gradually decreased with rising oxygen content, utilizing the oxygen that had been stored. Three microbes in this study were proven to be biofilm producers. One of these organisms had the fastest and highest degradation rate as evidenced in Figure 6.  
Several authors have demonstrated the effectiveness of the biodegradability test using DCPIP, emphasizing its importance in identifying microorganisms such as fungi, bacteria, and yeast that have the capability to break down petroleum and its derivatives [63; 64; 65]. The DCPIP assay has been found to be useful as a result of its quick detection of microorganism ability to degrade chemicals, along with it being a relatively cheap method [66]. The DCPIP assay enables the confirmation of the degradation capacity when choosing microorganisms to be used in bioremediation processes, and in this study, the degradation activity of the bacteria and fungi strain can be observed in the quantitative test, after 16 h of incubation. The quantitative test of the biodegradability of petroleum carried out by absorbance readings, showed a reduction in the concentration of DCPIP due to the degrading activity of the bacteria and fungi strain after 24 h of incubation as seen in Figure 6a. The biodegradation of petroleum hydrocarbons is known to be limited by a variety of causes, many of which have been explored by [PERSON] [7]. When determining whether a remediation strategy is appropriate, the composition and intrinsic biodegradability of petroleum hydrocarbon pollution are the most crucial factors to take into account. Temperature is one of the physical elements that have a significant impact on the biodegradation of hydrocarbons because it directly affects the chemistry of the pollutants, as well as the variety and physiology of the microbial flora. This study had a controlled temperature as observations were made ex situ. In the environment, such as in soils, sediments, aerosols, water, and organisms, the presence of PAHs and their derivatives can have detrimental consequences on ecosystems and human health by having mutagenic and carcinogenic effects [67]. One of the crucial phases in the polycyclic aromatic hydrocarbon (PAH) carcinogenic process is their binding with DNA [68]. According to research by [PERSON] et al. [69], contact with soil in polluted areas can expose people to the carcinogen benzo[\(\alpha\)] pyrene (B[\(\alpha\)]P) through their skin.