Nonaqueous biotechnology utilizing organic solvents tolerant ligninolytic enzymes

Lignin-degrading basidiomycetes have been known to secrete ligninolytic enzymes such as lignin and manganese peroxidases (LiP and MnP) and laccase. Since these enzymes play an important role in fungal metabolism of environmentally persistent aromatic compounds, including water-insoluble dioxin and biphenyl derivatives, we attempted to utilize them in nonaqueous media. Although these enzymes catalyze one-electron oxidation reactions, their electron transfer mechanisms are not the same. Therefore, the optimal method for each ligninolytic enzymes to utilize in organic media is different. To obtain stable ligninolytic activities in organic media, a peptide-hydrolyzed cytochrome c (microperoxidase-11), a dendritic porphyrin, and surfactant-coated MnP and laccase were prepared. Microperoxidase-11 was very stable in water miscible solvents such as methanol and ethanol, showing MnP activity as well as a peroxidase activity. The dendritic porphyrin oxidized both veratryl alcohol and 2, 6-dimethoxyphenol in benzene and chloroform. To obtain MnP and laccase complexes with surfactant molecules, a novel preparation method utilizing water-in-oil emulsions has been developed. LiP exhibited stable activity in isooctane when it was encapsulated in a reversed micelle.