Multistrategy metabolic engineering of Talaromyces pinophilus for α-amylase production from lignocellulosic biomass

High-cell-density fermentation of Komagataella phaffii enables the overproduction of a novel, broad-substrate endoglucanase, WcEG394 from Fuling (Wolfiporia cocos), for lignocellulose biorefining.

Recombinant WcEG394 efficiently hydrolyzed carboxymethyl cellulose, microcrystalline cellulose, and filter paper, and demonstrated broad substrate specificity toward xylans, pectin, chitin, agarose and agricultural residues such as corn cob and sugarcane bagasse.

Heterologous Expression of a Neurospora crassa Catalase Reprograms the Cellulase System and Enhances β-Glucosidase Production in Trichoderma reesei

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.

Metabolic Engineering of Yarrowia lipolytica for High-Level de novo Biosynthesis of Xylitol from Glucose.

Xylitol is a highly functional sweetener with extensive applications. Sustainable biosynthesis from glucose is desirable yet metabolically challenging. Here, we engineered Yarrowia lipolytica as a cell factory by constructing a core biosynthetic route via combinatorial screening and multicopy integration of d-arabitol dehydrogenases (ArDH) and an NADPH-dependent xylitol dehydrogenase (XDH) in the robust chassis NBRC1631. To further drive the metabolic flux and alleviate bottlenecks, we employed a synergistic push-and-pull strategy: overexpressing glucose transporters (YH3 and YH4), while upregulating pentose phosphate pathway enzymes (ZWF1 and GND1) to enhance NADPH regeneration, matching the redox demand of the synthetic cascade. Following two-stage pH-controlled fed-batch fermentation in a 3 L bioreactor, the final engineered strain achieved a record-high xylitol titer of 39.0 g/L with a yield of 0.09 g/g glucose. This study establishes a productive platform for microbial de novo xylitol biosynthesis from glucose, offering a green and economically viable route for industrial production.

Metabolic engineering of Dunaliella salina enhances astaxanthin production: combined effects of heterologous enzyme co-expression and dual-stress optimization

Comparative Genomic and Transcriptomic Analyses of 60Co-Mutagenized Scheffersomyces stipitis Strains: Identification of Candidate Genes Associated with High-Ethanol-Producing Xylose-to-Ethanol Fermentation

60 candidate key genes associated with high xylose-to-ethanol yield in S. stipitis are identified, predominantly involved in the cell cycle pathway, including CDC15 and PHO81.

Burkholderia lata BL02 Galactolipase as an Important Biocatalyst for Plant Biomass Deconstruction and Sugar Ester Synthesis

The transition toward sustainable biorefinery processes requires efficient strategies for lignocellulosic biomass deconstruction and valorization. In this study, an integrated enzymatic system combining fungal holocellulases and laccases with a bacterial galactolipase was developed and evaluated. The consortium, composed of Trametes hirsuta GMA-01, Mycothermus thermophilus CBS 619.91, and Burkholderia lata BL02, was produced using agro-industrial substrates and applied to the hydrolysis of different lignocellulosic biomasses. The incorporation of galactolipase activity enhanced the saccharification yields for leaf-derived substrates, reaching up to 292.0 mg/g for spinach leaves and 236.0 mg/g for corn straw, compared to fungal systems alone. This effect is associated with the selective hydrolysis of membrane-associated galactolipids, improving substrate accessibility to holocellulolytic enzymes. Proteomic analysis confirmed the partial identification of the BL02 enzyme as an ester hydrolase, while structural modeling based on homologous Burkholderia lipases provided preliminary insights into features that may be compatible with the accommodation of bulky polar substrates. In addition, the enzyme catalyzed the synthesis of sugar fatty acid esters with conversion yields above 50% for glucose and xylose in binary solvent systems. These findings support the role of galactolipases as accessory enzymes and highlight their potential application in integrated and sustainable biorefinery processes.