Biotechnology Research International / 2012 / Article / Tab 6

Review Article

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

Table 6

Environmental friendly application of enzymes.

Industrial sectorDescriptionEnzyme applicationReference

Fine chemical productionBiocatalysis 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 chemicalHydrolases are most prominent enzyme used in production of fine chemicals by biocatalytic resolutionSchulze and Wubbolts [85]

Biopolymers/plasticsEnzymes or whole cell systems use sugars as feedstock for product manufacturingMicrobial/enzyme emulation of fossil fuel process

Nutritional oil productionGenetically enhanced biomass (e.g., soybeans) to yield oil with improved properties, especially functional and nutritional qualityIncreasing concentration of conglycinin, a seed storage proteinHarlander [86]

Ethanol productionFeed stock is cellulosic biomass (e.g., corn ears and stalks, wheat straw, or switchgrass)Recent advances in cellulose enzymes have improved efficienciesKnauf and Moniruzzaman [87]

Leather degreasingDeveloping proteases for use in soaking, dehairing, and bating processesProteases 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 activityThanikaivelan et al. [88]

Biohydrogen productionH2 reactions catalyzed by either nitrogenase or hydrogenase enzymesE. 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 conditionsUS Department of Energy, Office of Science [89]

Chemical/biological warfare agent decontaminationEnzymatic processes can speed the decomposition of organophosphate nerve agents and other warfare agentsBacterial enzymes catalyze hydrolysis from bacteria genetically modified to express protein variants, for example phosphotriesterase and organophosphorus anhydrolaseRichardt and Blum [90]

Pulp and paper bleachingXylanase 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 processesEnzyme 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 reductionRoncero et al. [91]

Electroplating/metal cleaningEnzymes make degreasing/metal cleaning. Fungi can be used to treat metal-laden wasteProteases 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].

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