Alleviating vacuolar transport improves cellulase production in Trichoderma reesei

Area of Science:

• Biotechnology
• Molecular Biology
• Industrial Microbiology

Background:

• Cellulase production by Trichoderma reesei is crucial for biofuels and biorefineries.
• Accumulation of secreted proteins in vacuoles can limit cellulase yield.
• Alleviating vacuolar transport is a potential strategy to enhance cellulase secretion.

Purpose of the Study:

• To investigate the impact of disrupting vacuolar protein sorting (VPS) genes on cellulase production in T. reesei.
• To identify specific VPS genes that, when knocked out, lead to increased cellulase secretion.
• To elucidate the mechanisms underlying enhanced cellulase production in the knockout mutants.

Main Methods:

• Gene knockout of VPS10, VPS13, and VPS21 in T. reesei.
• Measurement of filter paper activity and β-glucosidase activity.
• Analysis of vacuolar trafficking and autophagy processes.
• Transcriptome analysis to assess gene expression changes.

Main Results:

• Knockout of vps10, vps13, and vps21 significantly increased filter paper activity (1.28- to 2.45-fold) and β-glucosidase activity (3.22- to 3.56-fold).
• Vacuolar transport was partially impaired in the knockout mutants, and vps13 disruption alleviated autophagy.
• Cellulase gene expression, particularly in vps13 and vps21 mutants, increased in the late induction phase, potentially due to altered sugar transporter expression.

Conclusions:

• Disruption of vps10, vps13, and vps21 enhances cellulase production in T. reesei by impairing vacuolar transport and degradation.
• Vps13 and Vps21 may regulate cellulase production at the transcriptional level, possibly through effects on sugar transporters.
• Targeting vacuolar transport pathways presents a promising avenue for improving cellulase yield in industrial applications.