Efficient one-pot lactic acid production from cellulose via a Trichoderma reesei and Bacillus coagulans cooperation leveraging substrate-induced secretomes.
Jun 2026· Bioresource Technology· pp.
135276
· 0 citations· 42 references
Medicine
TL;DR
This work provides an induction-based strategy for designing efficient microbial consortia and offers insights for improving the efficiency and sustainability of lignocellulosic biorefining.
Abstract
The high cost of cellulase production presents a major bottleneck in lignocellulosic biorefining. Herein, we investigated the role of secretomes induced by different substrates in mediating the synergistic interplay of Trichoderma reesei (T. reesei) and Bacillus coagulans (B. coagulans) for efficient lactic acid production. Substrate crystallinity directly affects the expression levels and enzymatic profiles in T. reesei, thereby influencing its hydrolytic performance. High-crystalline substrate induced a more balanced cellulase system, whereas low-crystallinity substrate favored the production of a β-glucosidase-enriched cocktail. This "substrate-enzyme-function" relationship was leveraged to construct a CBP system in which B. coagulans compensates for the intrinsic β-glucosidase deficiency of T. reesei through its efficient cellobiose metabolism. The synergistic cooperation achieved a near-theoretical lactic acid yield of 96.41% from cellulose without external enzyme supplementation. This work provides an induction-based strategy for designing efficient microbial consortia and offers insights for improving the efficiency and sustainability of lignocellulosic biorefining.
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
The high cost of commercial enzyme cocktails remains a major barrier for lignocellulosic (second-generation) bioethanol production. Simultaneous saccharification and fermentation (SSF) at elevated temperatures using enzyme-secreting yeast can reduce enzyme demand, but is constrained by the limited thermotolerance of industrial strains. In this study, thermotolerant isolates of an inhibitor-tolerant, xylose-utilizing, enzyme-secreting industrial Saccharomyces cerevisiae strain were generated using whole-genome transformation (WGT). Screening in mixed-sugar fermentations at 41 °C identified several improved isolates, of which one isolate, designated Cellusec®4.0, achieved an ethanol titer of 5.45%(v/v), representing an 86% increase compared to the parental strain. This was driven by near-complete utilization of glucose, xylose, and cellobiose. In SSF at 40 °C with sorghum pulp, Cellusec®4.0 reached 5.83%(v/v) ethanol, 24% higher than the parental strain. Fed-batch SSF of pretreated softwood demonstrated the benefit of elevated temperature, with Cellusec®4.0 achieving 4.36%(v/v) ethanol at 40 °C, 29% higher than at 35 °C. In addition, fed-batch SSF of alkali-pretreated sugarcane bagasse at 39 °C using an in-house produced enzyme cocktail resulted in ethanol titers of up to 8.0% (v/v) within 48 h, corresponding to an 83% yield. These results demonstrate that WGT is an effective strategy to introduce thermotolerance into industrial yeast while maintaining key traits. The improved thermotolerance of Cellusec® 4.0 enabled high-temperature SSF, thereby increasing ethanol titers. Combined with retained inhibitor tolerance, enzyme secretion, and mixed-sugar utilization, this supported efficient ethanol production across multiple lignocellulosic substrates under industrially relevant conditions.
Bart Thevelein, Mekonnen M Demeke, Stijn De Graeve et al.· Bioresource Technology· 0 citations
Production and characterize of β-glucosidases from the crude extract of the cyanobacterium Microcystis aeruginosa CACIAM 03 reinforce the promising enzymatic potential of M. aeruginosa strains isolated from the Amazon region for sustainable biotechnological applications.
G. Serra, M. S. Diniz, E. Gonçalves et al.· Biotechnology and applied bi...· 0 citations
BSEG2 is highly thermostable, tolerant of high salt and ionic liquids, and notably resistant to cellobiose inhibition up to 200 mM, suggesting potential to reduce freshwater demand in biomass processing and a strong candidate for simplified, cost-effective enzyme formulations for glucose production from lignocellulosic feedstocks.
Debjyoti Ghosh, Aditi Konar, Yi Gao et al.· Biotechnology Journal· 0 citations
Fungal cellulases are key biocatalysts for lignocellulosic biomass valorization and the development of sustainable biorefineries and 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