World journal of microbiology & biotechnology最新文献

Combinatorial engineering strategies were performed to improve cellulase production efficiencies of Aspergillus niger. Single functional cellulases in Aspergillus niger were knocked out with the exogenous multifunctional cellulases. Non-cellulase enzymes of phytase, β-mannanase and pectinase were deleted out from Aspergillus niger. The exogenous protein disulfide isomerase was expressed in Aspergillus niger. The cellulase activities from the reconstructed Aspergillus niger increased from 0.62 U/mL to 7.96 U/mL. Glucose released from corn stover increased from 12.5 g/L to 27.8 g/L. Deleting non-cellulase enzymes, expressing the multifunctional cellulase and exogenous protein disulfide isomerase could enhance cellulase production efficiencies of Aspergillus niger.

The present study aims to isolate and investigate temporal variability of the halophilic and halotolerant microbiota present in brine from former salt mine Solivar, Prešov (Slovakia) especially with respect to with their ability to produce polyhydroxyalkanoates (PHA). Brine sampling was performed in the year 2020 and 2021 and samples were inoculated on the R2A medium with 5% NaCl for the bacterial isolation. We obtained a total of 53 halophilic isolates and one halotolerant isolate, all of which were tested for their ability to produce PHA via Nile Blue A staining, Raman spectroscopy and Gas chromatography. The low diverse halophilic microbiota was dominated by Proteobacteria members (mainly Halomonas, Halovibrio, and Chromohalobacter sp.) and some of these bacteria represent newly identified taxa. Around 80% of the isolates were able to produce PHA during growth on glucose-rich media, which highlights the importance of PHA for adaptation to high-salinity environments. Poly(3-hydroxybutyrate) (PHB) was the main type of PHA produced with the yield up to 2.76 g/L in Halovibrio sp. HP20-59. Overall, our investigation pointed out that brine from Solivar shows genetically variable community of halophilic bacteria most of which are capable of accumulation of PHA, hereby confirming the high biotechnological potential of halophilic bacteria.

This study presents a comparative metagenomic analysis of the gut bacterial communities of two sugarcane-infesting mealybug species, Phenacoccus saccharifolii (WR) and Dysmicoccus carens (RR), from Tamil Nadu, India. Using Oxford Nanopore sequencing of the 16s rRNA gene spanning the hypervariable regions V1 - V9 and predictive metagenomics, differences in microbial diversity, taxonomy, and functional potential were assessed to explore the ecological adaptations of the gut microbiota in mealybugs. The D. carens gut microbiome showed higher species richness than P. saccharifolii (WR) (125 vs. 45 species, p < 0.05) but lower community evenness (0.43 vs. 0.61, p < 0.05), resulting in similar overall Shannon diversity (2.08 vs. 2.30) despite markedly different community structures, which may be influenced by their different feeding niches, including the sugarcane crown region, leaf sheath tissues, and basal stem and root portions. Both mealybug species exhibited contrasting bacterial community structures. D. carens (RR) harbored high abundances of endosymbionts (43.8%), Gilliamella (22.3%), Enterobacter (18.3%), and Candidatus Tremblaya (9.3%), representing a symbiont-dominated microbiome typical of many hemipteran insects. P. saccharifolii (WR) displayed a distinct profile with Serratia as the dominant genus (43.2%), followed by Enterobacter (20.1%), Klebsiella (14.6%), and substantially reduced endosymbiont abundances (14.8%). Beta diversity analysis revealed distinct community clustering of species, highlighting the variation driven by feeding habitat and host genotype. Functional profiling indicated largely conserved metabolic capabilities dominated by amino acid and carbohydrate metabolism, which was a key to compensate the nutrient-poor phloem sap diet. The core microbiome identified several genera that form complex ecological networks, emphasizing their importance in community stability. These findings provide insights into the role of symbiotic bacteria in mealybug adaptation to different ecological niches within the sugarcane agroecosystem. Understanding these host-microbiome interactions may facilitate the development of targeted, microbiome-based biocontrol strategies for sustainable mealybug management in sugarcane cultivation.

The continuous rise in greenhouse gas concentrations poses an irreversible threat to the earth system, while soil depletion and degradation are gradually eroding the basis of human survival. Therefore, the development of efficient technologies that combine carbon reduction and soil improvement is imperative. Although various carbon fixation and soil remediation methods have emerged in recent years, most of them have limitations such as single effects, complex operations, and high costs. This study proposed and validated a composite system based on biochar synergistic microbially induced carbon fixation (BC-MICF), which demonstrated dual advantages in carbon dioxide fixation and soil structure improvement. The research results indicated that after the application of the BC-MICF system, the carbon fixation potential of the soil reached 17703.8 mg, and the carbon fixation rate increased to 83.58 mg C•m^- 2•d^- 1, representing an 10948.90% and 9768.00% increase compared to the S group. Furthermore, the content of large-diameter soil aggregates (diameter > 2 mm) increased by 218%, soil structural stability and water stability increased by 84.07% and 48.43%, respectively, basic nutrient retention rates increased by 7.49%-10.25%, porosity increased by 68.94%, significantly improving soil water conductivity, air permeability, and enhancing its water retention, fertilizer retention, and erosion resistance capabilities. The BC-MICF system not only effectively reconstructed soil ecological functions and hydrological characteristics, but also achieved the goal of stably storing atmospheric CO₂ in the soil, thereby transforming soil from a "carbon source" to a "carbon sink", thus providing a novel technical path and theoretical support for simultaneously addressing the dual crises of climate change and land degradation.

This article systematically reviews the interactions of sulfate-reducing bacteria (SRB) with iron-oxidizing bacteria (IOB), iron-reducing bacteria (IRB), methanogenic archaea (MA), anaerobic Clostridia, and nitrate-reducing bacteria (NRB) in a multi-species system and their effects on microbial corrosion (MIC). Breaking through the limitations of single-microorganism research, the focus was on analyzing the complex effects of multi-species synergy or competition on corrosion, such as the intensification of pitting corrosion through the interaction of metabolic products between SRB and IOB/IRB. SRB competes with MA for substrates to regulate the corrosion path; NRB inhibits SRB activity through Bio-competitive exclusion (BCX); Clostridia enhances the corrosion efficiency of SRB through sulfite reduction, metabolic substrate supply and biofilm interweaving. The research also emphasized the regulatory role of environmental factors (such as pH, dissolved oxygen, temperature, substrate concentration) on microbial behavior and corrosion, providing a theoretical basis for MIC control in complex environments. This article differs from previous reviews in providing a more comprehensive summary of the corrosion mechanism mediated by multi-bacterial biofilms. It offers more systematic research data for future researchers in the field of microbial corrosion and points out the direction for the development of green anti-corrosion strategies such as ecological regulation and composite corrosion inhibition. It has significant guiding significance for the prevention and control of microbial corrosion in the oil and gas industry.

Microalgae are increasingly recognized as versatile platforms for sustainable production of biofuels and high-value bioproducts such as lipids, carotenoids and polyunsaturated fatty acids. Rapid progress in synthetic biology is transforming microalgal engineering by enabling precise rewiring of metabolic pathways and overcoming long-standing technical bottlenecks, particularly those related to transformation efficiency, genetic stability and strain scalability. Recent innovations (including CRISPR/Cas genome editing, modular cloning systems, synthetic promoter libraries and dynamic, environment-responsive regulatory circuits) have greatly expanded the genetic toolset available for both model and recalcitrant species. These advances support targeted control of lipid and pigment biosynthesis, improved flux distribution and more robust performance under industrially relevant conditions. When integrated with progress in photobioreactor design, automated cultivation, and process intensification, synthetic biology unlocks new potential for scalable, economically viable microalgal biomanufacturing. This review summarizes these developments, highlights remaining challenges in strain robustness and bioprocess translation, and outlines future pathways toward high-performance microalgal biofactories that can contribute meaningfully to a low-carbon, bio-based economy.

To address waste management challenges, lignocellulosic industrial co-products can be valorized microbially to propose sustainable and economically viable alternatives to fossil routes. This study advances a bio-based ethyl acetate microbial production by the yeast Kluyveromyces marxianus by investigating glucose availability under iron-limiting fed-batch conditions. Two feeding strategies were compared: one that maintained an excess of glucose and one that operated at zero residual glucose to understand their respective effects on ethyl acetate synthesis dynamics. Metabolite productions and kinetics were quantified across both conditions, enabling the evaluation of metabolic flux distributions in K. marxianus, rarely explored in the literature. Our results demonstrate that EA production rates observed under iron deficiency conditions cannot be attributed solely to iron limitation. As this study demonstrates, EA synthesis is multifactorial and depends on respiratory chain efficiency, pyruvate flux distribution and acetyl-CoA management. Herein, ethyl acetate synthesis was modelled via mitochondrial Eat1 enzyme and intracellular fluxes were analyzed under both iron and glucose-controlled culture conditions using a compartmented metabolic model of K. marxianus. Despite iron limitation, excess glucose preserves electron transport chain and tricarboxylic acid cycle activities, favoring metabolic balance over biomass. In contrast, glucose limitation promotes growth, consequently leading to downregulation of tricarboxylic acid cycle flux, constrained oxaloacetate synthesis and mitochondrial acetyl-CoA accumulation, thereby activating EA synthesis. These findings refine existing hypotheses and underscore the necessity of finely tuning electron transport chain and tricarboxylic acid cycle fluxes to induce mitochondrial acetyl-CoA overflow to optimize ethyl acetate production from lignocellulosic substrates.