Biotechnological Tools for Environmental Sustainability: Prospects and Challenges for Environments in Nigeria—A Standard Review

Table 6

Environmental friendly application of enzymes.

Industrial sector	Description	Enzyme application	Reference
Fine chemical production	Biocatalysis using selectivity of enzymes for one of the enantiomers of a chiral molecule, that is, one enantiomer of a racemate is unaffected and the other enantiomer is converted into the desired, pure chemical	Hydrolases are most prominent enzyme used in production of fine chemicals by biocatalytic resolution	Schulze and Wubbolts [85]
Biopolymers/plastics	Enzymes or whole cell systems use sugars as feedstock for product manufacturing	Microbial/enzyme emulation of fossil fuel process
Nutritional oil production	Genetically enhanced biomass (e.g., soybeans) to yield oil with improved properties, especially functional and nutritional quality	Increasing concentration of 𝛽-conglycinin, a seed storage protein	Harlander [86]
Ethanol production	Feed stock is cellulosic biomass (e.g., corn ears and stalks, wheat straw, or switchgrass)	Recent advances in cellulose enzymes have improved efficiencies	Knauf and Moniruzzaman [87]
Leather degreasing	Developing proteases for use in soaking, dehairing, and bating processes	Proteases from Aspergillus tamarii and Alcaligenes faecalis and loosen hair without chemical assistance. Alkaline protease produced from Rhizopus oryzae through solid-state fermentation dehairs the skins completely; use of enzymes for dehairing; baterial cultures have keratinolytic activity	Thanikaivelan et al. [88]
Biohydrogen production	H2 reactions catalyzed by either nitrogenase or hydrogenase enzymes	E. coli, Enterobacter aerogenes, and Clostridium butyricum use multienzyme systems. Can continuously produce H2 photochemically and nonphotochemically. Nitrogenase enzymes from Rhodopseudomonas palustris and Rhodobacter sphaeroides generate H2 under N-limited conditions	US Department of Energy, Office of Science [89]
Chemical/biological warfare agent decontamination	Enzymatic processes can speed the decomposition of organophosphate nerve agents and other warfare agents	Bacterial enzymes catalyze hydrolysis from bacteria genetically modified to express protein variants, for example phosphotriesterase and organophosphorus anhydrolase	Richardt and Blum [90]
Pulp and paper bleaching	Xylanase is applied before bleaching, replacing Cl-containing compounds in the first stage of the five-stage bleaching sequence. While rot fungus (Phanerochaete chrysosporium) degrades lignin in bioreactor wood chips injected with fungus and a growth medium, incubate for 2 weeks, followed by traditional chemical or mechanical processes	Enzyme replaces traditional Cl-addition. Biotechnology process reduces the amount of Cl-containing compounds by more than 10%. Bioreactor method reduces bleaching-related energy requirements by 40%, with concomitant pollution reduction	Roncero et al. [91]
Electroplating/metal cleaning	Enzymes make degreasing/metal cleaning. Fungi can be used to treat metal-laden waste	Proteases may be similar to those listed for leather degreasing Aspergillus japonicus used to sorp metal ions, for example, Fe (II), Ni (II), Cr (VI), and Hg (II)	Ahluwalia and Goyal [92]

Source: adapted from: [93].