been synthesized applying recombinant strains expressing TDO [81]. In spite of the synthesis of cis-dihydrodiols, various monooxygenases and dioxygenases which intrinsically catalyze hydrocarbons have been endowed with new functions for oxidizing indole into indigo. Indole is actually a prevalent nitrogen-containing aromatic pollutant in coking wastewater; nevertheless, it may be utilized for the production of indigo by means of biotransformation. Besides, numerous oxygenases have been reported to become capable to oxidize indole, including cytochrome P450, naphthalene dioxygenase (NDO), monooxygenase, and flavin monooxygenase (FMO). For example, NDO genes from Comamonas sp. MQ was heterogenous expressed in E. coli, resulting inside a high rate of conversion towards indole and its derivatives [82].Table 1. A summary of lately reported microbes and enzymes employed in industrial synthesis. Microorganism Sphingobium yanoikuyae B1 Burkholderia cepacia G4 Enzyme Activity Rieske oxygenase (RO) Toluene ERĪ² manufacturer ortho-monooxygenase (TOM) Relevant Industrial Synthons cis-dihydrodiols isoindigo indigo, indirubin, and isatin two,3-cis-dihydrodiol Toluene Chlorobenzene Bromobenzene Naphthalene 1,2-cis-dihydrocatechol Naphthalene (R)-1,2-phenylethanediol two,3-Substituted catechols 4-Substituted Phenol 3,4-Substituted Catechol 1-Naphthol Phenol 2-Naphthol Styrene oxide Epoxide 3-methylbenzylalcohol and 2,4-dimethylphenol 2-hydroxy ketone Reference [83] [84]Pseudomonas putida UVToluene dioxygenase (TDO)[85]Escherichia coli BW25113 Sphingomonas sp. CHY-1 Pseudomonas sp. NCIB 9816 Pseudomonas sp. species Pseudomonas mendocina KR1 Pseudomonas putida S12 Escherichia coli TG1 Pseudomonas putida S12 Pseudomonas putida KT2440 Rhodococcus sp. DK17 Pseudomonas putida KTTDO Naphthalene dioxygenase (NDO) NDO Dihydrocatechol dehydrogenase (DHCD) Toluene-4-monooxygenase (T4MO) TOM-Green Toluene-4-monooxygenase (T4MO) Styrene monooxygenase (SMO) SMO o-xylene dioxygenase -transaminases[86] [87] [88] [89] [90] [91] [92] [93] [94] [95] [96]4. Conclusions and Perspectives The dissipation of recalcitrant residual pollutants within the atmosphere is influenced by diverse biological ALDH3 Source processes, which includes microbial biodegradation, biosorption, phytoremediation, and so on. In recent instances, a expanding concern on the harmful effects of environmental contaminants has led to a marked boost in investigation into many approaches that can be adopted to clean up the contaminated environment. We are just beginning to understand and thus, completely exploit the natural sources for bioremediation. At the present stage, we are able to describe novel strains, enzymes, and metabolic routes involved in bacterial-mediated pollutant degradation. The rise of new biotechnologies in the last decade has enabled to unlock the functional potential of microbial-assist bioremediation. Many microorganisms with outstanding catabolic potential, specially those originating from extremely polluted environments, have been isolated and characterized. In certain, several enzymes, especially created by these uncultivable bacteria, have been discovered thanks to the omics strategy. Presently, many sophisticated approaches, such as metagenomics, proteomics, transcriptomics, andMolecules 2021, 26,ten ofmetabolomics, are successfully employed for the characterization of pollutant-degrading microorganisms, novel proteins, and catabolic genes involved inside the degradation process. These revolutionary sophisticated molecular practices deliver deeper insights into microbial activities concerni