Trichoderma reesei (T. reesei), a filamentous fungus, has emerged as a pivotal organism in the realm of cellulase production, garnering significant attention from researchers due to its exceptional cellulolytic properties and the potential for genetic manipulation to enhance enzyme yields. Cellulases, a group of enzymes that catalyze the hydrolysis of cellulose into glucose, hold immense importance in various biotechnological applications, including biofuel production, waste management, and the textile industry. As a model organism, T. reesei offers a unique platform for studying the mechanisms underlying cellulase production, which encompasses genetic regulation, enzymatic pathways, and the influence of environmental factors such as substrate type, light, and metal ions. Multi‐omics analyses have elucidated novel aspects of cellulase production mechanisms, and concurrent advances in genetic engineering provide new strategies for optimizing enzyme synthesis in T. reesei. Despite the progress made, several unresolved questions remain regarding the regulatory mechanisms of cellulase genes, highlighting the need for future research to explore these gaps and further enhance our understanding of cellulase production. This literature review aims to synthesize current knowledge on the mechanisms of cellulase production in T. reesei, discuss recent advancements, and outline future research opportunities that could lead to significant breakthroughs in this field.
Efficient saccharification of lignocellulose, the most abundant renewable carbon reservoir resource, is of great industrial importance. Trichoderma reesei is a premier cellulase producer, but its fermentation efficiency is often constrained by dual challenges: dissolved oxygen limitation and intrinsic oxidative stress. To address this, we engineered T. reesei to heterologously express a robust catalase gene (cat-3) from Neurospora crassa. The recombinant strain Tr-cNcat3 exhibited a 7.4-fold increase in extracellular catalase activity. Tr-cNcat3 showed an increase in total extracellular protein, resulting in markedly enhanced filter paper activity (FPA) and β-glucosidase activity compared to the control. Strikingly, this intervention specifically triggered a significantly higher expression of β-glucosidase, a known bottleneck in T. reesei’s cellulase system, particularly on bagasse and straw as the carbon source. Moreover, the ability of the supernatant to degrade cellulose substrates was improved. Our results reveal that overexpression of cat-3 in T. reesei could modify the cellulase cocktail by triggering a higher level of β-glucosidase. This study provides a novel and effective genetic engineering strategy to unlock the full industrial potential of T. reesei for cost-effective lignocellulosic biorefining.
Haowen Sun, Chang-Bin Tang, Yifan Chen et al.· Journal of Fungi· 0 citations
These findings define the core oxidative machinery underlying biomass deconstruction in T. reesei, revealing the major cellulose-oxidative role of TrLPMO9A and the importance of a cooperative redox network for efficient lignocellulose depolymerization.
Priscila T Rodrigues, C. R. Terrasan, N. Bulka et al.· Biotechnology for Biofuels a...· 0 citations
Fungal cell factories serve as a robust platform for sustainable biomanufacturing, owing to their unparalleled metabolic diversity, enzymatic properties, and resilience to diverse environmental conditions. Recent advances in fungal biotechnology have vastly enhanced the potential for fungi to be used in the production of renewable bioenergy and functional biomaterials. Concurrent advances in systems biology, metabolic engineering, and synthetic biology have enabled the fine-tuning of metabolic fluxes to facilitate the enhanced biosynthesis of biofuels, including bioethanol, biodiesel, biogas, and biohydrogen, as well as mycelium-derived biopolymers. The lignocellulolytic fungi like Trichoderma reesei, Aspergillus niger, and Phanerochaete chrysosporium have been the main organisms of focus with respect to engineering, which enhances hydrolytic enzyme excretion, growth on substrates, and redox balance in these fungi. This engineering work parallels a new ability in omics technologies and CRISPR–Cas genome editing, permitting the facilitation and identification of regulation of biosynthetic gene clusters responsible for lipid accumulation, secondary metabolite production, and nanomaterial synthesis in fungi. Furthermore, new fungal-derived biomaterials have been reported, such as chitosan, β-glucans, and mycelium composites, which have been advanced as biodegradable alternatives to plastics and building materials derived from petroleum. This review critically reviews some of the more recent developments in respect of the reprogramming of fungal metabolism, process intensification strategies and integrated biorefinery applications. This will illustrate the convergence of fungal systems biology with the principles of circular bioeconomy and point out the technological, economic, and regulatory bottlenecks which need to be overcome to fully realise the potential of fungi as the biofactories of the future for the sustainable production of energy and materials.
Babita Thakur, Sukhminderjit Kaur, Ranjan Singh et al.· Journal of Pure and Applied...· 0 citations
Fungal cellulases are key biocatalysts for lignocellulosic biomass valorization and the development of sustainable biorefineries. This review examines recent advances in the production of endoglucanase (EGL), exoglucanase (EXG), and β-glucosidase (BGL) by fungi of the genera Trichoderma, Aspergillus, and Penicillium under solid-state fermentation (SSF) and submerged fermentation (SmF). Emphasis is placed on fermentation strategies, substrate selection, process optimization, and emerging chemometric and artificial intelligence-based approaches. The literature reveals a predominance of SSF systems, especially when agri-food residues such as wheat bran, sugarcane bagasse, rice-derived residues, fruit-processing wastes, and cocoa by-products are employed as low-cost substrates. Among the evaluated genera, Aspergillus was among the most frequently investigated genera and exhibited broad substrate versatility, whereas Trichoderma reesei remains the principal industrial production host for cellulase-rich enzyme preparations used mainly in the saccharification of lignocellulosic biomass for cellulosic ethanol and other biorefinery applications. In contrast, Penicillium stands out as an important source of BGL, complementing cellulase systems derived from other fungi. Temperature, pH, moisture content, and fermentation time were consistently identified as the main factors affecting cellulase biosynthesis, with optimal production generally occurring under mildly acidic conditions and mesophilic temperatures. CCD and BBD were the predominant optimization strategies, while artificial neural network-based models are emerging as promising alternatives. The complementary characteristics of these fungi genera support their application in integrated biomass conversion and future lignocellulosic biorefineries.
I. V. L. de Moura, S. Araujo, I. C. F. Sampaio et al.· Biomass· 0 citations
Gibberellic acids (GAs) are a class of tetracyclic diterpene carboxylic acid compounds produced by green plants, fungi, and bacteria, which have a wide range of applications in agricultural production and food ingredients processing. Owing to the continuously growing market demand, enhancing GA yield has become imperative. The biosynthesis of GAs is a multi-enzymatic synergistic process that can be enhanced through genetic and metabolic engineering strategies. In this review, we first summarize recent advances in GA production by Fusarium fujikuroi. We then highlight key metabolic engineering strategies, including biosynthetic pathway engineering, cluster-specific channeling of geranylgeranyl diphosphate biosynthesis, cofactor engineering, as well as regulatory mechanisms involving nitrogen modulation and histone modification. Finally, we discuss promising approaches for constructing high-efficiency microbial cell factories, such as implementation of the CRISPR/Cas9 system, the application of strong promoters, the development of target-specific technologies for small molecules, and the employment of genome-scale metabolic models. Recent metabolic engineering efforts have achieved GA3 titers of up to 3.16 g/L through multi-target nitrogen regulation strategies, highlighting the potential for further yield improvement.