Preliminary Appraisal of Tomato Waste as a Fermentation  Substrate for Cellulase Production

Constança Isabel Reis Sabino

Key information

Authors:

Constança Isabel Reis Sabino (Constança Isabel Reis Sabino)

Supervisors:

Luís Joaquim Pina da Fonseca (Luís Joaquim Pina da Fonseca)

Published in

December 5, 2025

Abstract

Lignocellulosic biomass, the most abundant renewable source of organic carbon, represents a sustainable alternative to fossil-based feedstocks for biofuel and biochemical production. Among these residues, tomato waste – rich in proteins, carbohydrates, and minerals - holds significant potential for valorization. This work investigates the feasibility of using enzymatically hydrolyzed tomato paste waste, an abundant by-product from Portuguese tomato processing industries, as a substrate for submerged fermentation with Trichoderma reesei RUT C-30 to achieve substrate-tailored cellulase production. Promising results were obtained, with cellulase activities of 0.52, 0.67 and 0.44 FPU/mL during batch fermentations with progressed substitution of the control medium with tomato waste, and 0.83, 0.50 and 3.22 FPU/mL during fed-batch shake-flask fermentations – comparable to those achieved with a chemically defined medium (0.93 FPU/mL and 0.81 FPU/mL). Upon scale-up to a 5 L bioreactor, enzyme activities reached 2.21 FPU/mL for the control medium and 2.97 FPU/mL for the tomato hydrolysate. These findings demonstrate the potential of tomato waste as a viable, low-cost substrate for on-site cellulase production, contributing to industrial waste valorization and circular bioeconomy initiatives.