## 3 Results and Discussion
### Archaeal Community in Both bioreactors  
Archaea play a significant role in anaerobic degradation, particularly in methanogenesis. In bioreactor 1, the genus Methanocorpusculum (21.92%) was predominant, whereas its presence in bioreactor 2 was significantly reduced (0.47%). On the other hand, the genera Methanothrix (16.56%) and Methanosarcina (4.15%) dominated in bioreactor 2, indicating an active methanogenic process (Figure 6). The genus Methanomassiliicoccus (5.86%) was also identified in bioreactor 2, consistent with the studies of [PERSON] et al. (2015) [42], which report its role in the degradation of methyl compounds. Notably, a high abundance of archaea from the class Thermoproteei (50.81%) was observed in bioreactor 2, which is due to the specific thermophilic and acidophilic environment.  
Previously [41], archaea from the phylum Euryarchaeota represented 11.4% of the microbial community in bioreactor 2, whereas, in the present study, Methanothrix and Methanosarcina together accounted for approximately 20.7%. This suggests that the methanogenic process described here may have higher activity or a different profile of methanogenic pathways, potentially related to the use of different substrates. A study by [PERSON] et al. (2012) [43] found that Methanosarcina dominated anaerobic bioreactors using industrial waste, which is similar to our findings for bioreactor 2.  
Except the biotechnology we described, other technologies were also applied. Bioelectrochemical-system-anaerobic digestion enhances the electron transfer activity between microorganisms and their resistance to toxic and hazardous substances by means  
Figure 6: Relative abundance of the archaeal communities in hydrogen bioreactor and methane bioreactor classified to genus level.  
of electrical currents, making the process stable and faster. It is applied as a strategy for enhancing the performance of anaerobic digestion [44]. However, it is a complex process to accomplish, considering the reactor size and applied voltage, external electric fields, etc. Pyrolysis is applied according to the substrate used to convert plastic waste into valuable products like fuel oil, solid residue, and combustible gas. Various types of plastic waste can be processed [45]. Methane pyrolysis technologies for hydrogen production requires high temperatures to overcome the activation energy barriers [46]. The technology can be chosen in relation to the substrates, conditions, microbial consortia, bioreactors construction, performance, and cost-effectiveness.  
The advantage of the TSAD system is that it produces hydrogen, together with methane. We have in mind that biohydthane is a gaseous mixture of 10-30% H\({}_{2}\) and 70-90% CH\({}_{4}\), whose physicochemical properties are similar to natural gas. Biohythane has superior characteristics compared to other biofuels. When addressing vehicles powered by methane, the use of hythane (with 30% H\({}_{2}\)) can achieve a CO\({}_{2}\) emission reduction of about 70 gkm\({}^{-1}\). In order to obtain high-quality hythane for less carbon dioxide emissions, the ratio between the volumes of the bioreactors must be properly selected, together with other characteristics [47]. Finally, biohydthane has a high fuel efficiency and pollution control than petrol and diesel, and can be obtained by the biotransformation of organic wastes.