Study of Ganoderma lucidum in Laccase Production using Corncob and Paddies Straw Substrates on Submerged Fermentation System

Background and objective: Ganoderma lucidum a white rot fungi, produce laccase which capable to degrade lignin due to its activity as ligninolytic enzymes. The production of laccase by G. lucidum using various agroindustrial wastes, including corncob and paddies straw, as substrates have been studied. The purpose of this study was to determine substrate that able to produce the highest activity of the laccase from the G. lucidum.

Materials and methods: The method used an experimental design followed by descriptive analysis using 4 treatments with duplication including treatment G. lucidum growth into A (control, Potato Dextrose Broth (PDB)), B (PDB+corncob), C (PDB+rice straw) and D (PDB+corncob+rice straw). This study includes; (1) Qualitative assay determination of laccase, (2) Extraction and laccase activity, (3) Cell concentration of G. lucidum measurement and (4) pH measurement.

Results: Laccase qualitative assay showed brownish red ring on PDA media that indicated a positive of the laccase enzyme secreted by G. lucidum. Enzyme activity under submerged fermentation condition was achieved by the treatment of adding corncobs with the highest activity accounting 68.75 U mL-1. The fermentation process causes a decrease in pH during the incubation time to pH 4.83. The results of pH measurements showed that the laccase enzyme from G. lucidum worked optimally at pH 4-5 achieved after 5 day of incubation.

Conclusion: Our results suggest that G. lucidum has potential to produce laccase enzyme by using substrate comprising corncob and rice straw on submerged fermentation.

Keywords: G. lucidum; Laccase; agroindustrial waste; corncob; ligninolytic enzyme; paddies straw.