Search Results (54)

Large-scale bioprocesses often suffer from spatial heterogeneities, which impact microbial performance and often lead to phenotypic population heterogeneity. To better understand these effects at the single-cell level, this study applied, for the first time, automated real-time flow cytometry (ART-FCM) to monitor L-phenylalanine production with an Escherichia coli triple reporter strain in a fed-batch process with glycerol as the carbon source. The strain was cultivated in both a well-mixed stirred-tank bioreactor (STR) and a scale-down two-compartment bioreactor (TCB), consisting of an STR and a coiled flow inverter (CFI) in bypass, to simulate spatial heterogeneities. ART-FCM enabled autonomous, high-frequency sampling every 20 min, allowing for real-time tracking of fluorescence signals linked to growth (rrnB-mEmerald), oxygen availability (narGHIJ-CyOFP1), and product formation (aroFBL-mCardinal2). The STR exhibited uniform reporter expression and higher biomass accumulation, while the TCB showed delayed product formation and pronounced phenotypic diversification depending on the set mean residence time in the CFI. Single-cell fluorescence distributions revealed that the shorter mean residence time in the CFI resulted in pronounced subpopulation formation, whereas longer exposure attenuated heterogeneity, indicating transcriptional adaptation. This finding highlights a critical aspect of scale-down studies: increased exposure duration to perturbations can enhance population robustness. Overall, this study demonstrates the relevance of ART-FCM, in combination with a multi-reporter strain, as a pioneering tool for capturing dynamic cellular behavior and correlating it to process performance, providing deeper insights into microbial heterogeneity under fluctuating bioprocess conditions. Full article

Nanobiotechnology applications in plant tissue culture have improved the development and physiology of explants, resulting in plants with high genetic homogeneity and phytosanitary quality. Silver nanoparticles (AgNPs) are well-known for their microbicidal properties, but their biochemical effects on plants require further exploration. In this work, green-synthesized AgNPs were evaluated in strawberry in vitro culture, photosynthetic pigment production, and acclimatization. AgNPs produced by Lysinibacillus fusiformis were characterized. Strawberry explants were grown in vitro on MS medium with 0, 100, 200, and 300 mg L⁻¹ AgNPs at 24 ± 2 °C and a photoperiod of 16:8 h light/dark. Shoot height and number, number of leaves, number of roots, and root length were evaluated, and chlorophyll (a, b, and total) was quantified. Rooted shoots were acclimatized ex vitro on substrates containing 0 and 200 mg L⁻¹ AgNPs. The results showed that low AgNPs concentrations had a positive impact on shoot multiplication, development, and rooting, but at higher concentrations, the effects decayed. However, chlorophyll production improved with increasing AgNP concentration. Shoots treated with AgNPs showed higher ex vitro survival. Our study has direct implications for the profitability and sustainability of commercial strawberry production. Full article

Venturia inaequalis, the cause of apple scab, readily develops resistance to fungicides with specific modes of action. Knowledge of the spatial and temporal pattern of resistance development is therefore relevant to fruit producers and their consultants. In the Lower Elbe region of Northern Germany, a two-year survey based on a conidial germination test was conducted, examining fungicide resistance in 35 orchards under Integrated Pest Management (IPM), 16 orchards of susceptible cultivars as well as a further 12 orchards of scab-resistant (Vf) cultivars under organic management, and 34 abandoned or unmanaged sites. No evidence of resistance to SDHI compounds (fluopyram, fluxapyroxad) was found after >5 yr of their regular use. Resistance to anilinopyrimidines (cyprodinil, pyrimethanil) had disappeared 15 yr after its widespread occurrence. Isolates from a few IPM orchards showed a reduced sensitivity to dodine. Double resistance to the MBC compound thiophanate-methyl and the QoI trifloxystrobin was rare in V. inaequalis strains that had achieved breakage of Vf-resistance, but very common (>50%) on scab-susceptible cultivars in IPM, organic and abandoned orchards in the ‘Altes Land’ core area of the Lower Elbe region, and in IPM orchards in the periphery. We conclude that resistance to QoI and MBC fungicides is persistent even decades after their last use, and that the core area harbours a uniform population adapted to intensive crop protection, whereas isolated orchards in the periphery are colonised by discrete populations of V. inaequalis. Full article

The growing demand for functional foods has driven the search for bioactive compounds derived from plant proteins. Lupinus mutabilis “Tarwi”, a legume native to the Peruvian Andes, stands out for its high protein content and potential as a source of bioactive peptides (BPs). In this study, the functionality of the proteins contained in the albumin fraction (AF) isolated by tangential ultrafiltration (TFF) was investigated by using the OmicsBox software. The identified proteins were functionally classified into three groups: cellular component (35.57%), molecular function (33.45%), and biological process (30.97%). The isolated AF was hydrolysed with the native protease PC7 (HAP), optimizing the E/S ratio and time parameters. Additionally, sequential hydrolysis of the PC7 protease and alcalase (HAPA) was performed. In vitro multifunctionality assays, HAP and HAPA demonstrated the ability to scavenge radicals (ABTS and ORAC) and inhibit angiotensin-converting enzyme (ACE)-I and dipeptidyl peptidase IV (DPP-IV). The findings of this study highlight the potential of L. mutabilis albumin hydrolysate as a multifunctional ingredient for functional foods aimed at managing chronic conditions associated with oxidative stress, hypertension, and/or metabolic disorders. Full article

The study of new strains of basidiomycetes as sources of biologically active substances is a promising direction in modern biotechnology. This work aims to isolate new cultures of the fungi Daedaleopsis tricolor, Pycnoporellus fulgens and Trichaptum abietinum from natural fruiting bodies and to improve their growth conditions on solid nutrient media. The identification of fungi was performed based on their morphological features and using the Sanger sequencing method. Cultivation was carried out by placing inoculum in the middle of a Petri dish and at the edge, which provided a more comprehensive definition of the characteristics of colonies and fungus hyphae. New strains were registered in Genbank Overview. The optimal cultivation temperature was 27 °C for all studied strains. The highest radial growth was observed on synthetic medium for D. tricolor (5.26 mm/day) and T. abietinum (7.5 mm/day), and on synthetic medium with lignin for P. fulgens (2.98 mm/day). The biomass amount of D. tricolor KS11 was 133.25 mg at 9 days of cultivation, that of P. fulgens KS12 was 86.73 mg at 16 days, and that of T. abietinum KS10 was 227.33 mg at 6 days. New strains of fungi can be used to obtain biologically active substances for the food, pharmaceutical and cosmetic industries. Full article

Globally, people are cultivating finger millet, an important cereal, to improve food availability and health benefits for humans. However, the biotechnological research on this millet is limited and insufficient in this field. The primary focus of this study is to optimize an efficient regenerated protocol for initiating further plant transformation studies, using the shoot apex as an explant and various growth regulators. For example, three cytokinins (BAP, TDZ, and Kin) at different concentrations were used to induce multiple shoots of finger millet. Among these, TDZ (4.5 µM) provided the maximum number (17.3) of shoots as compared to BAP and Kin. IBA (2.46 µM), along with MS medium, was used for the induction of roots, where 5.6 roots were produced in an individual shoot and the length of the root was longer with a size of 8.2 cm after two weeks of incubation. The clonal fidelity of the in vitro regenerated plantlets of finger millet was confirmed by ISSR primers. Overall, the present work developed a robust and reliable procedure for the establishment of efficient and reproducible regeneration through the shoot apex that will be useful for the genetic improvement of this crop. The genetic enhancement of these millets as well as the successful creation of transgenic plant varieties modified for resistance to biotic and abiotic challenges in the near future would be aided by this study. Full article

Natural compounds with significant bioactive properties can be found in abundance within biomasses. Especially prominent for their anti-inflammatory, neuroprotective, antibacterial, and antioxidant activities are cinnamic acid derivatives (CAs). Ferulic acid (FA), a widely studied phenylpropanoid, exhibits a broad range of therapeutic and nutraceutical applications, demonstrating antidiabetic, anticancer, antimicrobial, and hepato- and neuroprotective activities. This research investigates the green enzymatic synthesis of innovative and potentially bifunctional prodrug derivatives of FA, designed to enhance solubility and stability profiles. Selective esterification was employed to conjugate FA with xylitol, a biobased polyol recognized for its bioactive antioxidant properties and safety profile. Furthermore, by exploiting t-amyl alcohol as a green solvent, the enzymatic synthesis of the derivative was optimized for reaction parameters including temperature, reaction time, enzyme concentration, and molar ratio. The synthesized derivative, xylitol monoferulate (XMF), represents a novel contribution to the literature. The comprehensive characterization of this compound was achieved using advanced spectroscopic methods, including ¹H-NMR, ¹³C-NMR, COSY, HSQC, and HMBC. This study represents a significant advancement in the enzymatic synthesis of high-value biobased derivatives, demonstrating increased biological activities and setting the stage for future applications in green chemistry and the sustainable production of bioactive compounds. Full article

The production of microbial metabolites such as (exo)polysaccharides, lipids, or mannitol through the cultivation of microorganisms on sustainable, low-cost carbon sources is of high interest within the framework of a circular economy. In the current study, two non-extensively studied, non-conventional yeast strains, namely, Cutaneotrichosporon curvatus NRRL YB-775 and Papiliotrema laurentii NRRL Y-3594, were evaluated for their capability to grow on semi-defined lactose-, glycerol-, or glucose-based substrates and produce value-added metabolites. Three different nitrogen-to-carbon ratios (i.e., 20, 80, 160 mol/mol) were tested in shake-flask batch experiments. Pretreated secondary cheese whey (SCW) was used for fed-batch bioreactor cultivation of P. laurentii NRRL Y-3594, under nitrogen limitation. Based on the screening results, both strains can grow on low-cost substrates, yielding high concentrations of microbial biomass (>20 g/L) under nitrogen-excess conditions, with polysaccharides comprising the predominant component (>40%, w/w, of dry biomass). Glucose- and glycerol-based cultures of C. curvatus promote the secretion of mannitol (13.0 g/L in the case of glucose, under nitrogen-limited conditions). The lipids (maximum 2.2 g/L) produced by both strains were rich in oleic acid (≥40%, w/w) and could potentially be utilized to produce second-generation biodiesel. SCW was nutritionally sufficient to grow P. laurentii strain, resulting in exopolysaccharides secretion (25.6 g/L), along with dry biomass (37.9 g/L) and lipid (4.6 g/L) production. Full article

Natural compounds are increasingly favored over synthetic ones for their lower environmental impact. However, extraction and characterization processes typically rely on harsh conditions and conventional solvents, which are unsustainable and cause pollution. This study aimed to develop an eco-friendly extraction method to isolate and evaluate the antimicrobial properties of bioactive compounds from Chlorella sorokiniana. Using dimethyl carbonate (DMC), methoxycyclopentane (CPME), and butan-2-one (MEK) as green solvents alongside chloroform as a non-green reference solvent, on both untreated and sodium hydroxide pre-treated microalgae biomass, extract yields of up to 182 ± 27 mg/g DW were obtained using MEK. Extracts from untreated microalgae biomass exhibited lower MIC values compared to those obtained with the same solvent from pre-treated biomass, when tested as antimicrobial agents against Escherichia coli, Bacillus megaterium, and Bacillus subtilis. The lowest MIC value (4.89 ± 0.05 µg/mL) was observed against E. coli using the extract from the untreated microalgae biomass with CPME, which was comparable to the vancomycin control (1.55 ± 0.03 µg/mL). Principal component analysis highlighted correlations between GC-MS-identified compounds and antimicrobial activity. ANOVA and post hoc tests (p < 0.05) confirmed solvent choice, and pre-treatment influenced yield and bioactivity. The results underscore green solvents as sustainable alternatives for extracting bioactive compounds from autotrophic microalgae. Full article

The present study aimed to chemically profile the hydroalcoholic extracts from the microalgae (MEs) Nannochloropsis oculata, Phaeodactylum tricornutum, Tetradesmus obliquus, and Tetraselmis tetrathele and evaluate their effects on the development of Colletotrichum lindemuthianum and anthracnose symptoms, as well as on the initial growth of bean plants. For this, MEs were analyzed using UPLC coupled with a mass spectrometer, allowing the identification of peaks and annotation of potential metabolites. Fungal mycelial growth was assessed seven days after inoculation, and conidial germination was measured 72 h after incubation, using ME concentrations of 0, 0.1, 0.5, and 1.0 mg·mL⁻¹. Bean seeds of the IPR Uirapuru cultivar were sown and treated with 3 mL of extracts at four time points: at sowing and 72 h after each previous treatment. After 11 days of cultivation in a growth chamber, the plants were divided into two groups: one for anthracnose control assessment and the other for evaluating growth promotion by MEs. Plant length as well as fresh and dry weights of shoots and roots were determined, leaf pigments were quantified, and anthracnose severity was assessed using a diagrammatic scale. The UPLC analysis identified 32 compounds in the extracts of the four microalgae, belonging to different chemical and functional groups, with lipids being the most significant fraction. The extracts exhibited variability and diversity in chemical composition depending on the microalgal species. MEs did not affect mycelial growth yet increased the germination of C. lindemuthianum conidia, regardless of the dose or species used. Anthracnose severity was not affected by the microalgae extracts. Regarding growth promotion, the extracts showed varying effects but generally increased shoot and root length, fresh biomass, and leaf pigment content. Full article

Field crops are expected to be increasingly threatened by climate change, which will negatively impact plant development, growth and yield. Phytohormones play a crucial role in regulating specific signalling pathways to induce rapid adaptive responses to environmental stresses. Exogenous phytohormone application alters hormonal balance, thereby enhancing plant adaptation to adverse conditions. While several studies have advanced our understanding of the use of phytohormones in field crops, yield responses and species-specific application strategies remain inconsistent and rarely assessed under field conditions. The application of cytokinins (CKs), abscisic acid (ABA), and gibberellic acid (GA) has been shown to maintain prolonged photosynthetic activity, stabilize plasma membrane, and reduce lipid peroxidation and ion accumulation under salinity stress in wheat. Additionally, inhibitors of ethylene synthesis and receptors can mitigate stress symptoms under drought and heat stress, which typically accelerates senescence and shortens the grain-filling period in cereal crops. In this way, exogenous application of CKs, GA, and ethylene inhibitors can delay senescence by sustaining leaf photosynthetic activity and postponing nutrient remobilization. However, these benefits may not consistently translate into improvements in grain yield and quality. This review explores the molecular mechanisms of phytohormones in abiotic stress tolerance, delineates their specific functions and evaluates experimental findings from field applications. It also summarizes the potential of phytohormone applications in field crops, emphasizing the need for species-specific investigations on application timing and dosages under open-field conditions to optimize their agronomic potential. Full article

The sprout market in Korea is expanding as consumers seek healthier food options and farmers strive to increase added value and competitiveness. This study examined the changes in the phytochemical composition of Sinpalkwang (SPK), a peanut variety developed in Korea, during germination. Four samples (SPK1, SPK2, SPK3, and SPK4) were collected at different growth stages and analyzed for total polyphenol content (TPC), total flavonoid content (TFC), and antioxidant activities using ABTS⁺ and DPPH assays. The levels of trans-resveratrol and soyasaponin Bb were quantified using high-performance liquid chromatography (HPLC) with a photo-diode array (PDA). Among the samples, SPK2 exhibited the highest TFC (1.61 mg QE/g ext.) and trans-resveratrol content (0.054 mg/g ext.), while SPK4 showed the highest TPC (29.38 mg TAE/g ext.) and soyasaponin Bb content (6.543 mg/g ext.). In terms of radical scavenging activities, SPK2 and SPK3 performed best in the ABTS⁺ and DPPH assays, respectively. Germinated samples demonstrated strong results across all analyses, highlighting the benefits of germination in enhancing phytochemical properties. This study provides foundational information on the phytochemical composition of SPK and the effects of germination. Future research will focus on optimizing germination conditions to further enhance the functionality and value of this Korean-bred variety as a source of high-value bioactive ingredients. Full article

Bioelectrochemical systems (BESs) are devices capable of converting chemical energy into electrical energy using microorganisms as catalysts. These systems have been extensively studied at the laboratory level, but, due to multiple difficulties, their large-scale implementation has been explored only sparingly. This study presents the most recent technological advances for scaling up BESs. In the same way, the main technical and economic challenges that hinder the correct implementation of these systems at a large scale are mentioned. The study concludes with a review of successful case studies in scaling up BESs and discusses future directions and emerging trends. Full article

In recent times, microalgae have emerged as powerful hosts for biotechnological applications, ranging from the production of lipids and specialized metabolites (SMs) of pharmaceutical interest to biofuels, nutraceutical supplements, and more. SM synthesis through bioengineered pathways relies on the availability of aromatic amino acids (AAAs) as an essential precursor. AAAs, phenylalanine, tyrosine, and tryptophan are also the building blocks of proteins, maintaining the structural and functional integrity of cells. Hence, they are crucial intermediates linking the primary and specialized metabolism. The biosynthesis pathway of AAAs in microbes and plants has been studied for decades, but not much is known about microalgae. The allosteric control present in this pathway has been targeted for metabolic engineering in microbes. This review focuses on the biosynthesis of AAAs in eukaryotic microalgae and engineering techniques for enhanced production. All the putative genes involved in AAA pathways in the model microalgae Chlamydomonas reinhardtii and Phaeodactylum tricornutum are listed in this review. Full article

Organisms from the genus Streptomyces feature actinobacteria with complex developmental cycles and a great ability to produce a variety of natural products. These soil bacteria produce more than 2/3 of antibiotics used in medicine, and a large variety of bioactive compounds for industrial, medical and agricultural use. Although Streptomyces spp. have been studied for decades, the engineering of these bacteria remains challenging, and the available genetic tools are rather limited. Furthermore, most biosynthetic gene clusters in these bacteria are silent and require strategies to activate them and exploit their production potential. In order to explore, understand and manipulate the capabilities of Streptomyces spp. as a key bacterial for biotechnology, synthetic biology strategies emerged as a valuable component of Streptomyces research. Recent advancements in strategies for genetic manipulation of Streptomyces involving proposals of a large variety of synthetic components for the genetic toolbox, as well as new approaches for genome mining, assembly of genetic constructs and their delivery into the cell, allowed facilitation of the turnaround time of strain engineering and efficient production of new natural products at an industrial scale, but still have strain- and design-dependent limitations. A new perspective offered recently by technical advances in DNA sequencing, analysis and editing proposed strategies to overcome strain- and construct-specific difficulties in the engineering of Streptomyces. In this review, challenges and recent developments of approaches for Streptomyces engineering are discussed, an overview of novel synthetic biology strategies is provided and examples of successful application of new technologies in molecular genetic engineering of Streptomyces are highlighted. Full article