Effect of novel cutinase CcCut1 in degrading potato suberin and berry cutin

Cutinases catalyze the hydrolysis of natural cuticular polyesters (cutin, suberin) tolower molecular weight components. These enzymes are thus potentially valuabletools for by-product exploitation in agricultural industry. Cutin and suberin polymers are composed of long chain non-substituted and hydroxy/epoxy-substituted ? hydroxy fatty acids and a,?-dicarboxylic acids. A novel cutinase CcCUT1 (from Coprinus cinereus) was investigated for degradation of potato suberin and black currant cutin. Cutinase hydrolysis and chemical methanolysis of suberin were compared and the CHCl3-soluble monomeric fragments identified as TMS derivatives with GC-MS. The solid, hydrolysis-resistant residues of suberin were analyzed with solid state 13C CP-MAS NMR and FT-IR. The cutinase hydrolysis resistant residual microstructures, of both potato suberin and black currant cutin, were analysed by light and confocal microscopy. Gravimetrical analysis showed that methanolysis was more effective than cutinase treatment for releasing CHCl3-soluble material. The results of the analysis of monomeric components indicate that cutinases are more specific towards a,?-dioic acids than ?-hydroxy acids. Spectroscopic analysis and microscopy of the residues further revealed the mode of action.