## 1 Introduction
Twenty MFCs based on the developed consortium, when connected to electrical series-parallel connections, were able to generate 2.3 V and a current of 0.5 mA. The potential for possible further applications of these hybrid MFCs-based systems for the decomposition of complex organic pollutants present in industrial wastewaters has been demonstrated [81]. Using MFCs, the possibility of oil wastewater treatment with simultaneous generation of electricity and COD decrease was investigated. Through oxidation in the MFCs systems with activated sludge, bioelectricity was generated and used in the cathode chamber [82]. The petrochemical wastewater from an acrylic acid planet with a high COD value has been investigated as a substrate for generating electricity in a dual-chamber of MFC with anaerobic sludge as a sample of BCs [83]. Despite the seemingly great prospects of MFCs, the expediency of their industrial implementation in the purification processes of petrochemical wastewaters remains a big question due to the difficulties with the organization of economically justified technical design of such processes. So far, the use of MFCs as parts of hybrid processes related to solving problems in the pharmaceutical industry looks the most realistic [84]. It should be noted that not only microbial cells with a large set of enzymatic activities are considered as BCs but also individual enzymes, although they are rarely found as components of well-known industrial purification technologies. Enzymes are proposed for use in the hydrolysis of polyacrylamide in the composition of petrochemical wastewaters [85]. An enzyme such as lactose was covalently immobilized on NPs of amino-terminated silanized magnetite. The use of the obtained biom nanocomposites (bioNComs = \"laccase-magnetic\") enabled the treatment of artificial and real wastewaters with the extraction of the dye Eriochrome Black T and phenol. Optimal catalytic characteristics were achieved in the media with pH 4-4.5 [86]. Only lactose and other oxidoreducases (tyrosine and horseradish peroxidase) were considered for phenol degradation [87]. It is more expedient to consider the use of enzymes in the immobilized form [88], including as a component of bioNComs [86]. The combined use of BCs and NPs provides an increase in the efficiency of the processes of purification of various natural objects and wastewater from hydrogen pollution; therefore, it seems promising from the point of view of further improvement of purification processes. A bioNCom such as Fe\({}_{3}\)O\({}_{4}\)-NIL-DAS@lac, which is a lacase immobilized on magnetic NPs modified by amino-functionalized ionic liquid using di-aldehyde starch (DAS) as cross-linker (Fe\({}_{3}\)O\({}_{4}\)-NIL-DAS), was used to extract phenol and its derivatives from wastewater. The maximum removal efficiency was 86.1%, 93.6% and 100% for phenol, 4-chlorophenol and 2.4-dichlorophenol, respectively [69]. The addition of graphene oxide quantum dots (GOQDs) to the reaction medium with _Bacillus cereus_ cells caused the activation of cytokinesis and increased secretion of extracellular polymer compounds important for biofilm formation. As a result, an increase in the efficiency of decomposition of anthracene and phenanthrene was noted [67]. The combination of _Brevibacillus parabrev_ cells with Fe\({}_{3}\)O\({}_{4}\) magnetic nanoparticles contributed to an increase in the efficiency of tetradecane destruction due to Pickering emulsification and increased activity from BCs [64]. Chemically modified mesoporous silica NPs (mSNPs) (10 nm) were obtained, which represented a closed system with C\({}_{18}\)-hydrocarbon chains in a closed collapsed state in an aqueous medium that is capable of opening due to solvation by lipophilic alkanes and releasing its contents upon contact with the oil phase. NPs have been successfully tested for the delivery of additional nutrients to BCs during the biodegradation of crude oil with _Marinobacter hydrocarbonoclasticus_[66].