Characterization of cellulases from softening fruit for enzymatic depolymerization of cellulose

Area of Science:

• Biochemistry
• Plant Science
• Enzymology

Background:

• Cellulose is a key renewable resource for sustainable industries.
• Efficient enzymes for plant cell wall depolymerization are crucial for cellulose utilization.
• Plant-derived cellulases are less studied compared to microbial sources.

Purpose of the Study:

• To investigate cellulases from plant origins, specifically from bilberry (Vaccinium myrtillus L.), a fruit known for rapid softening.
• To identify and characterize glycoside hydrolase family 9 (GH9) cellulases involved in fruit ripening and softening.

Main Methods:

• Genome sequencing of bilberry and identification of GH9 cellulases.
• Phylogenetic, transcriptomic, and gene expression analyses to identify fruit ripening-specific enzymes.
• Expression and functional characterization of recombinant cellulases in Pichia pastoris.

Main Results:

• Identified 20 GH9 cellulases in bilberry, with four showing fruit ripening-specific expression.
• Characterized four secreted GH9 cellulases (two B-types, two C-types) with carbohydrate-binding modules.
• Recombinant enzymes exhibited glucanase activity on cellulose and hemicellulose; VmGH9C1 showed high degradation ability. Enzymes were stable across a wide pH (6-10) and temperature range (optimum 70°C).

Conclusions:

• Bilberry GH9 cellulases, particularly VmGH9C1, are effective in degrading lignocellulosic components.
• The identified plant cellulases exhibit desirable stability, indicating potential for industrial bioprocessing applications.
• This study highlights the potential of plant-derived enzymes for sustainable industrial biotechnology.