Increased tolerance to biomass-derived inhibitors by deletion of the transcriptional regulator mraZ in Cupriavidus necator H16.

Adaptive laboratory evolution of Lactiplantibacillus plantarum enhances furan tolerance and lactic acid production in lignocellulosic hydrolysate

Furfural and 5-hydroxymethylfurfural (HMF) are two major lignocellulosic growth inhibitors that hinder microbial growth and fermentation of lignocellulosic hydrolysate for lactic acid production. In this study, we employed adaptive laboratory evolution (ALE) to enhance the tolerance of Lactiplantibacillus plantarum JGR2, a strain previously isolated in our lab, to furfural and HMF. The adapted strains demonstrated significantly improved growth in the presence of these inhibitors compared to the parental strains. Whole-genome resequencing revealed multiple mutations including high-impact non-conservative mutations in genes encoding DNA recombination and repair protein (RecF, lp_0005), flavin prenyltransferase (UbiX lp_0271), and oligo-1,6-glucosidase (lp_0189). Transcriptomic analysis indicated that adaptation elicited more pronounced differential gene expression compared to acute inhibitor exposure. Upon furfural exposure, the furfural-adapted isolate showed fewer differentially expressed genes than the parental strain, indicating a possible shift in the transcriptomic profile as a possible mechanism of furfural adaptation. Mechanistic investigation revealed that the adapted isolates reduce furfural into the less toxic furfuryl alcohol, suggesting a key detoxification mechanism. Notably, lp_3051 (dhaT, 1,3-propanediol dehydrogenase) encoding furfural reductase activity was upregulated in both furfural- and HMF-adapted isolates. Membrane fatty acid analysis revealed increased unsaturated fatty acids and cyclopropane fatty acids in adapted strains. Finally, the adapted strains exhibited improved growth in rice straw hydrolysate and produced significantly higher relative lactic acid yields compared to the parental strain, thus demonstrating improved bioproduction under inhibitor-rich conditions. This study not only provides a comprehensive understanding of L. plantarum’s response to lignocellulosic inhibitors, but also yields evolved bacterial candidates for further scientific and industrial exploration.

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.

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

This study demonstrates the combined optimization of isozyme combination and environmental stress to elevate the synthesis of astaxanthin and other carotenoids in D. salina, providing new research ideas and experimental evidence for the future construction of high-yield engineered algal strains.

Identification and Overexpression of a Knotted1-Like Transcription Factor in Switchgrass ( Panicum virgatum L.) for Lignocellulosic Feedstock Improvement

ROS signaling mediates aeration-dependent thermotolerance in Kluyveromyces marxianus for high-temperature xylitol production.

This study uncovers that moderate reactive oxygen species (ROS) signaling mediates aeration-dependent thermotolerance in Kluyveromyces marxianus, challenging the long-held paradigm that ROS function solely as toxic metabolic byproducts. Through integrated transcriptomic profiling and RT-qPCR validation, 19 key transcription factors regulating this adaptive response were identified, and functional assays demonstrated that targeted knockout of GSF2 and RIM101 coupled with MED15 overexpression significantly enhances hypoxic thermotolerance. The ERG6-overexpressing strain YZB559 yields 72.45 g/L xylitol at 45 °C under medium-high oxygen (MHO) condition, marking a 20% improvement over the parental strain, while the combinatorially engineered YZB639 (ΔGSF2::MED15) achieves 74.13 g/L xylitol with complete xylose consumption at 46 °C and 30.64 g/L ethanol under micro-oxygen conditions, representing a 23% increase in ethanol production. Notably, at 47 °C, the highest temperature reported for xylitol fermentation, YZB639 accumulates 51.68 g/L xylitol under constant MHO condition, and an optimized two-stage oxygen supply strategy further elevates the titer to 67.78 g/L, with robust performance also observed when using industrial xylose mother liquor as feedstock to produce 57.34 g/L xylitol. This work resolves the fundamental oxygen contradiction between thermotolerance enhancement and product biosynthesis in high-temperature fermentation, providing a transformative strategy for cost-effective and sustainable industrial biomanufacturing.

Dual regulatory roles of the zinc cluster transcription factor MrFTRP1 in development, stress tolerance, and virulence of Metarhizium robertsii.

It is demonstrated that MrFTRP1 exerts a dual-regulatory functioning as a positive regulator of conidiation and pathogenesis but a negative regulator of environmental stress tolerance, which expands the understanding of the regulatory diversity within the C6 TF family and identifies him as a promising target for the genetic improvement of mycoinsecticides.