Genetics and chemistry of lignin degradation by Streptomyces. Final technical report
Our research goal was to define the involvement of lignin peroxidases and other extracellular enzymes in lignin degradation by Streptomyces. We examined the biochemistry and genetics of lignin degrading enzyme production by several strains of Streptomyces. The lignin peroxidase ALiP-P3 of S. viridosporus was characterized kinetically and its activity optimized for oxidation of 2,4-dichlorophenol and vanillyl-acetone. Sensitive spectrophotometric assays were developed for monitoring oxidation of these substrates. ALiP-P3 reaction chemistry was examined using both spectrophotometric assays and gas chromatography/mass spectroscopy. Results showed that the enzyme oxidizes phenolic lignin substructure models in strong preference to nonphenolic ones. The peroxidase was also shown to depolymerize native lignin. We also cloned the ALip-P3 gene S. lividans in plasmid vector pIJ702. The cloned gene was partially sequenced, We also immunologically characterized the lignin peroxidase of S. viridosporus T7A and showed it to be structurally related to peroxidases produced by other lignin-solubilizing Streptomyces, but not the the H8 lignin peroxidase of P. chrysosporium. Studies with peroxidase deficient mutants of strain T7A showed that lignin peroxidases of S. viridosporus are directly involved in the solubilization of lignin. Additional research showed that other enzymes are also probably involved in lignin solubilization, possibly including extracellular esterases.
- Research Organization:
- Idaho Univ., Moscow, ID (United States). Dept. of Bacteriology and Biochemistry
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG07-86ER13586
- OSTI ID:
- 10140506
- Report Number(s):
- DOE/ER/13586-T2; ON: DE93011726
- Resource Relation:
- Other Information: PBD: [1992]
- Country of Publication:
- United States
- Language:
- English
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