Yellow Laccase-Mediated Lignin Degradation of Ricinus communis: A Future Agricultural Biomass for Biofuel Production

Agricultural biomass left to decay in the fields and forests has a huge possibility to serve as a low-cost feedstock for production of bioethanol and other value added products. In the Indian subcontinent, Ricinus communis, growing in parched conditions contributes a major biomass containing 44.4 % cellulose, 22.8 % hemicelluloses and 19.8 % lignin. In the present study, response surface methodology based on central composite design and genetic algorithm has been used to explore the effects of pH, temperature, solid-to-liquid ratio (w/v), enzyme activity, and incubation time on enzymatic depolymerization of R. communis. The maximum delignification obtained was 86.7 %. Delignified biomass was characterized by Fourier transformed infrared spectroscopy and scanning electron microscopy. Lignin degradation products were identified by gas chromatography-mass spectroscopy. Cinnamic acid, p-coumaric acid (4-hydroxycinnamic acid), and ferulic acid (4-hydroxy-3-methoxycinnamic acid) were detected in the extract degraded by yellow laccase.