Title:Production of Highly Thermostable Laccase from Penicillium spinulosum
for Enhanced Delignification of Untreated Wheat Bran
Volume: 10
Issue: 2
Author(s): Folasade M. Olajuyigbe*, Ademola K. Oduwole and Cornelius O. Fatokun
Affiliation:
- Enzyme Biotechnology and Environmental Health Unit, Department of Biochemistry, Federal University of Technology,
Akure 340252, Ondo State, Nigeria
Keywords:
Biodelignification, laccase, wheat bran, Trichoderma koningii, Penicillium spinulosum, Penicillium restrictum.
Abstract: Background: Lignin confers rigidity on plant cell wall and poses a challenge to the hydrolysis
of cellulose, which makes the production of biofuels from lignocellulose an overwhelming
problem. This prompts a continuous search for novel ligninolytic enzymes, especially laccases for
delignification of lignocellulose for improved saccharification of biomass.
Objective: This study reports the production, physicochemical properties, and delignification efficiency
of laccases from Penicillium and Trichoderma species on untreated wheat bran.
Methods: Fungal laccases were produced using different agro residues (wheat bran, coconut shell,
and palm kernel shell) as substrates in submerged fermentation. The best substrate for laccase production
was determined. Physicochemical properties of crude enzymes and delignification efficiency
of the laccases were determined on untreated wheat bran using pure laccase as control.
Results: Wheat bran supported maximum laccase production from fungi under study. The highest
laccase yield of 22.5 U/mL was obtained from P. spinulosum. Laccase from P. spinulosum was optimally
active at pH 7.0 and 50°C and exhibited remarkable high thermostability with 61.6% residual
activity at 90°C after 2 h incubation. The activity of the thermostable enzyme was enhanced in
the presence of Cu2+. Biodelignification efficiency of cell-free extract from P. spinulosum, T. koningii,
and P. restrictum on wheat bran was 95%, 81.5%, and 63.5%, respectively. Surprisingly, a
much lower delignification efficiency of 33.42% was obtained with commercial laccase from Trametes
versicolor.
Conclusion: The high thermostability and striking delignification efficiency of crude laccase from
P. spinulosum make the enzyme a good bioresource for biodelignification of untreated lignocellulose
for biofuel production.
