Search Results (890)

Mushrooms are eukaryotic organisms with absorptive heterotrophic nutrition, capable of feeding on organic matter rich in cellulose and lignocellulose. Since ancient times, they have been considered allies and, in certain cultures, they were seen as magical beings or food of the gods. Of the great variety of edible mushrooms identified worldwide, less than 2% are traded on the market. Although mushrooms have been valued for their multiple nutritional and healing benefits, some cultures perceive them as toxic and do not accept them in their culinary practices. Despite the existing skepticism, several researchers are promoting the potential of edible mushrooms. There are two main methods of mushroom cultivation: solid-state fermentation and submerged fermentation. The former is the most widely used and simplest, since the fungus grows in its natural environment; in the latter, the fungus grows suspended without developing a fruiting body. In addition, submerged fermentation is easily monitored and scalable. Both systems are important and have their limitations. This article discusses the main methods used to increase the performance of submerged fermentation with emphasis on the modes of operation used, types of bioreactors and application of morphological bioengineering of filamentous fungi, and especially the use of intelligent automatic control technologies and the use of non-invasive monitoring in fermentation systems thanks to the development of machine learning (ML), neural networks, and the use of big data, which will allow more accurate decisions to be made in the fermentation of filamentous fungi in submerged environments with improvements in production yields. Full article

Soil respiration (Rt), consisting of heterotrophic (Rh) and autotrophic respiration (Ra), plays a vital role in terrestrial carbon cycling and is sensitive to soil temperature and moisture. In dryland agriculture, plastic film mulching (PM) is widely used to regulate soil hydrothermal conditions, but its effects on Rt components and their temperature sensitivity (Q₁₀) across regions remain unclear. A two-year field study was conducted at two rain-fed maize sites: Anding (warmer, semi-arid) and Yuzhong (colder, drier). PM significantly increased Rt, Rh, and Ra, especially Ra, due to enhanced root biomass and improved microclimate. Yield increased by 33.6–165%. Peak respiration occurred earlier in Anding, aligned with maize growth and soil temperature. PM reduced Q₁₀ of Rt and Ra in Anding, but only Ra in Yuzhong. Rh Q₁₀ remained stable, indicating microbial respiration was less sensitive to temperature changes. Structural equation modeling revealed that Rt and Ra were mainly driven by soil temperature and root biomass, while Rh was more influenced by microbial biomass carbon (MBC) and dissolved organic carbon (DOC). Despite increased CO₂ emissions, PM improved carbon emission efficiency (CEE), particularly in Yuzhong (+67%). The application of PM is recommended to enhance yield while optimizing carbon efficiency in dryland farming systems. Full article

Winery wastewater (WWW), if released untreated, poses a serious environmental threat due to its high organic load. In this study, Chlorella vulgaris was cultivated in diluted WWW to assess its suitability as a culture medium. Two outdoor cultivation systems—a 270 L raceway and a 40 L bubble column—were operated over 33 days using synthetic medium (control) and WWW. A flow cytometry (FC) protocol was implemented to monitor key physiological parameters in near-real time, including cell concentration, membrane integrity, chlorophyll content, cell size, and internal complexity. At the end of cultivation, the bubble column yielded the highest cell concentrations: 2.85 × 10⁶ cells/mL (control) and 2.30 × 10⁶ cells/mL (WWW), though with lower proportions of intact cells (25% and 31%, respectively). Raceway cultures showed lower cell concentrations: 1.64 × 10⁶ (control) and 1.54 × 10⁶ cells/mL (WWW), but higher membrane integrity (76% and 36% for control and WWW cultures, respectively). On average, cells grown in the bubble column had a 22% larger radius than those in the raceway, favouring sedimentation. Heterotrophic cells were more abundant in WWW cultures, due to the presence of organic carbon, indicating its potential for use as animal feed. This study demonstrates that FC is a powerful, real-time tool for monitoring microalgae physiology and optimising cultivation in complex effluents like WWW. Full article

Snails at hydrothermal vents rely on symbiotic bacteria for nutrition; however, the specifics of these associations in adapting to such extreme environments remain underexplored. This study investigated the community structure and metabolic potential of bacteria associated with two Indian Ocean vent snails, Chrysomallon squamiferum and Gigantopelta aegis. Using microscopic, phylogenetic, and metagenomic analyses, this study examines bacterial communities inhabiting the foot and gland tissues of these snails. G. aegis exhibited exceptionally low bacterial diversity (Shannon index 0.14–0.18), primarily Gammaproteobacteria (99.9%), including chemosynthetic sulfur-oxidizing Chromatiales using Calvin–Benson–Bassham cycle and methane-oxidizing Methylococcales in the glands. C. squamiferum hosted significantly more diverse symbionts (Shannon indices 1.32–4.60). Its black variety scales were dominated by Campylobacterota (67.01–80.98%), such as Sulfurovum, which perform sulfur/hydrogen oxidation via the reductive tricarboxylic acid cycle, with both Campylobacterota and Gammaproteobacteria prevalent in the glands. The white-scaled variety of C. squamiferum had less Campylobacterota but a higher diversity of heterotrophic bacteria, including Delta-/Alpha-Proteobacteria, Bacteroidetes, and Firmicutes (classified as Desulfobacterota, Pseudomomonadota, Bacteroidota, and Bacillota in GTDB taxonomy). In C. squamiferum, Gammaproteobacteria, including Chromatiales, Thiotrichales, and a novel order “Endothiobacterales,” were chemosynthetic, capable of oxidizing sulfur, hydrogen, or iron, and utilizing the Calvin–Benson–Bassham cycle for carbon fixation. Heterotrophic Delta- and Alpha-Proteobacteria, Bacteroidetes, and Firmicutes potentially utilize organic matter from protein, starch, collagen, amino acids, thereby contributing to the holobiont community and host nutrition accessibility. The results indicate that host species and intra-species variation, rather than the immediate habitat, might shape the symbiotic microbial communities, crucial for the snails’ adaptation to vent ecosystems. Full article

Kleptoplastidy is a nutrition mode in which cells of protists and some multicellular organisms acquire, maintain, and exploit chloroplasts of prey algae cells as photosynthesis reactors. It is an important aspect of the mixotrophic feeding strategy, which plays a role in the formation of harmful algae blooms (HABs). We developed a new mathematical model, in which kleptoplastidy is regarded as a mechanism of enhancing mixotrophy of protists. The model is constructed using three thought (theoretical) experiments and the concept of biological time. We propose to measure the contribution of kleptoplastidy to mixotrophy using a new ecological indicator: the kleptoplastidy index. This index is a function of two dimensionless variables, one representing the ratio of photosynthetic production of acquired chloroplasts versus native chloroplasts, and the other representing the balance between autotrophic and heterotrophic feeding modes. The index is tested by data for the globally distributed, bloom-forming potentially toxic mixotrophic dinoflagellates Prorocentrum cordatum. The model supports our hypothesis that kleptoplastidy can increase the division rate of algae significantly (by 40%), thus boosting their population growth and promoting blooms. The proposed model can contribute to advancements in ecological modeling aimed at forecasting and management of HABs that deteriorate marine coastal environments worldwide. Full article

Climate change can have a direct impact on the decomposition of organic matter, as well as indirect effects on peatland vegetation (including carnivorous plants) and the microbial communities associated with this environment. The activity of microbes varies depending on the type of peatland they inhabit. Because some microorganisms are highly sensitive, they can be used as indicators of climate change. However, there is still little knowledge of how changes in the temperature of the environment can affect the microbiome of carnivorous plants. The study was conducted to test the following hypotheses: (1) The effect of rising water temperature on the qualitative and quantitative structure of the microbiome of carnivorous peatland plants depends on the type of peatland; (2) habitats with a higher trophic status stimulate the development of microbial communities in the water, but are an unfavourable habitat for the development of the microbiome of plant traps. Irrespective of the type of peatland, the species richness of microorganisms was much higher in the water than in the traps. As the temperature increased, there was an increase in the abundance of bacteria, heterotrophic flagellates, and testate amoebae, which was much more pronounced in the peat bog than in the carbonate fen. Full article

Groundwater at petroleum-contaminated sites typically exhibits elevated dissolved inorganic carbon (DIC) levels due to hydrocarbon biodegradation; however, our prior field investigations revealed an enigmatic DIC depletion anomaly that starkly contradicts this global pattern and points to an unrecognized carbon sink. In a breakthrough demonstration, this study provides the first experimental confirmation that sulfur-oxidizing bacteria (SOB) drive substantial carbon sequestration via a coupled sulfur oxidation autotrophic assimilation process. Through integrated hydrochemical monitoring and 16S rRNA sequencing in an enrichment culture system, we captured the complete DIC transformation trajectory: heterotrophic acetate degradation initially increased DIC to 370 mg/L, but subsequent autotrophic assimilation by SOB dramatically reduced DIC to 270 mg/L, yielding a net consumption of 85 mg/L. The distinctive pH dynamics (initial alkalization followed by acidification) further corroborated microbial regulation of carbon cycling. Critically, Pseudomonas stutzeri and P. alcaliphila were identified as the dominant carbon-fixing agents. These findings definitively establish that chemolithoautotrophic SOB convert DIC into organic carbon through a “sulfur oxidation-carbon fixation” coupling mechanism, overturning the conventional paradigm of petroleum-contaminated sites as perpetual carbon sources. The study fundamentally redefines natural attenuation frameworks by introducing microbial carbon sink potential as an essential assessment metric for environmental sustainability. Full article

Urine-derived and plant-derived benzoic acid can accumulate within soil, and it likely changes the soil microbial community as well as N₂O emissions; however, its mechanism is not clear. This study conducted an incubation experiment to monitor N₂O emissions under low moisture (40% water-filled pore space (WFPS)) and high moisture (85% WFPS) conditions. Metagenomic sequencing and q-PCR methods were used to determine the link between N₂O emissions and the composition and functions of soil microbiota. Benzoic acid (BA) was found to significantly, yet dose-dependently, impact N₂O emissions; that is, low BA concentrations increased N₂O, whereas high BA decreased N₂O. However, this was only found under high moisture conditions. In contrast, BA had little impact on N₂O emissions under low moisture conditions. Under high moisture conditions, BA increased the gene copy number of bacteria and fungi, and decreased the ratio of bacteria to fungi. Similarly, BA significantly increased the abundance of denitrification functional genes, but reduced the (NirS + NirK)-to-NosZ ratio at the peak of emission. This is in agreement with the observation of the increased relative abundance of genes encoding N₂O reductase (EC 1.7.2.4) and NO₃⁻ heterotrophic reductase (EC 1.7.1.15, EC 1.7.2.2) in the metagenomic analysis. In summary, high concentrations of benzoic acid reduce N₂O emissions by promoting the reduction of N₂O. This study revealed the impact of BA on soil microbiota and highlighted the favorable conditions and underlying mechanism behind BA’s significant impact on soil N₂O emissions. This study’s novelty lies in the fact that it deepens our understanding of the complicated role of root exudates and metabolites of animals and plants in soil. Full article

In recent years, microalgae have gained significant biotechnological importance as a sustainable source of various metabolites of industrial interest. Among these, paramylon, a polysaccharide produced by the microalga Euglena gracilis, stands out for its diverse applications in biomedicine and pharmaceuticals. E. gracilis is an adaptable secondary eukaryote capable of growing photoautotrophically, heterotrophically and mixotrophically. During photoautotrophic growth, varying light conditions impact biomass and paramylon production. To investigate the effects of varying illumination more thoroughly, we designed and built a modular photobioreactor that allowed us to simultaneously evaluate the photoautotrophic growth of E. gracilis under twelve different light conditions: seven single-spectrum lights (ultraviolet, royal blue, blue, green, red, far-red, and infrared) and five composite-spectrum lights (3000 K, 10,000 K, and 30,000 K white lights, amber light, and “Full-spectrum” light). The 24-day growing kinetics were recorded, and the growth parameters were calculated for each light regime. Both growth curves and pigment composition present differences attributable to the light regime used for cell culture. Additionally, photosynthetic and respiratory machinery functionality were proven by oximetry. Finally, our results strongly suggest that the far-red component enhances paramylon production during the stationary phase. Full article

Powdered oil ingredients are widely used across food, nutrition, and personal care industries, but they are typically produced through encapsulation technologies that involve multiple additives and stabilizers. These systems can compromise oxidative stability, clean-label compliance, and functional performance. Here, we present the development and characterization of a novel high-oleic algal powder (HOAP) produced from a heterotrophically fermented microalgae. The production strain was developed through classical mutagenesis to enhance oleic acid and lipid accumulation. Three independent fermentation batches at a 20 L scale demonstrated strong reproducibility in key metrics, including dried-cell weight (210.0 g per L on average, CV% = 0.7), oil content (62.0% of DCW on average, CV% = 2.0), and oleic acid (88.8% of total fatty acids on average, CV% = 0.1). HOAP exhibited a favorable nutritional profile (e.g., high monounsaturated fat and fiber, low sugar and moisture) and good oxidative stability under ambient and accelerated storage conditions. Microbiological analyses confirmed compliance with food-grade standards, and in silico allergenicity screening revealed no clinically relevant homologs. Unlike traditional oil powders, HOAP does not require encapsulation and retains oil within a natural protein–fiber matrix, offering both functional and clean-labeling advantages. Its compositional attributes and stability profile support potential use in food, nutrition, and the delivery of bioactive nutrients. These findings establish HOAP as a next generation of oil powder ingredients with broad application potential. Full article

Coinfection poses severe threats to poultry health, particularly due to the complexity and resilience of multispecies interactions, increasing the difficulty of treatment. Haemophilus spp., a heterotrophic bacterium, heavily relies on extracellular growth factors acquired from other organisms or its surrounding environment. Although coinfections by Avibacterium paragallinarum and Bacillus have been reported, the underlying mechanism of the cooperative interaction remains poorly understood. In this study, we characterized the growth-promoting properties and nicotinamide adenine dinucleotide production of some Bacillus species, including probiotic Bacillus, to evaluate the feasibility of A. paragallinarum coinfection in vitro. Meanwhile, we determined the minimum inhibitory concentration (MIC) and population dynamics of cocultured Bacillus and A. paragallinarum to assess the effect of bacterial interactions on antibiotic efficacy. Additionally, we demonstrated that B. cereus aggravates rhinitis symptoms in chickens infected with A. paragallinarum. Our findings reveal that Bacillus spp.-derived metabolites sustain A. paragallinarum growth and enhance its survival, thereby highlighting the infection risks associated with Bacillus colonization in the respiratory tract. Full article

The transmission of infectious diseases via the use of public restrooms has been previously documented. The goal of this study was to compare bacterial contamination in public vs. household restrooms and, using quantitative microbial risk assessment (QMRA), to assess the probability of infection from fomite contact with selected high-touch sites within the restrooms. Fomite surfaces in four public and four household restrooms were sampled over a period of two months. The public restrooms were in an office building occupied by 80 individuals and were considered moderate usage. The toilet seat, toilet flush handle, countertops, and floor were sampled for heterotrophic, coliform, and Escherichia coli bacteria. The highest numbers of heterotrophic bacteria and coliforms were detected on the countertops, followed by the floor. The greatest numbers of E. coli were recovered from the countertops in the household restroom, but the greatest numbers in the public restroom were recovered from the toilet flush handle. Numbers of heterotrophic bacteria and coliforms were 10 to 100 times greater in household restrooms than in public restrooms. The QMRA suggested that the greatest risk of acquiring a norovirus infection involved the touching of the countertops in household restrooms and the toilet flush handles in public restrooms. Full article

Microorganisms take an active part in the processes of microbiologically influenced corrosion, which is protected against by using bactericides—often toxic compounds—with inhibitory properties. There are many studies of eco-friendly “green” biocides/inhibitors, in particular those based on microbial metabolites. Indicators for the processes of microbial corrosion of steel 3 induced by the sulfate-reducing bacteria Desulfovibrio oryzae NUChC SRB2 under the influence of the strains Bacillus velezensis NUChC C2b and Streptomyces gardneri ChNPU F3 have not been investigated, which was the aim of this study. The agar well diffusion method (to determine the antibacterial properties of the supernatants) was used, along with the crystal violet (to determine the biomass of the biofilm on the steel) and gravimetric methods (to determine the corrosion rate). A moderate adhesiveness to steel 3 was established for D. oryzae due to its biofilm-forming ability. The presence of a supernatant on cultures of S. gardneri, B. velezensis and their mixture (2:1) did not reduce the biofilm-forming properties of D. oryzae. Compared to the control, a decrease in the corrosion rate was recorded for the variant of the mixture of the studied bacterial culture supernatants. This indicates the potential of this mixture for use in corrosion protection in environments with sulfate-reducing bacteria, which requires further research. Full article

The structure of microbial communities in sponge-sand filters, used for the treatment of real domestic sewage with elevated ammonium nitrogen concentrations (approximately 155 mg·dm⁻³), was characterized using 16S rRNA gene sequencing. Analyses using the Illumina technique allowed us to perform a comparison of filters by layer (two or three layers) and type of fill (waste PUR foams with 95% open porosity, sand). Proteobacteria, actinobacteria, and firmicutes were shown to be the most abundant phyla. The number and type of fill layers had a significant impact on the diversity of nitrifying bacteria. The presence of Nitrosomonas and Nitrospira was observed in every sponge fill sample, but the abundance of autotrophic nitrifiers was negligible in the two-layer filter. The conditions there proved more favorable for the growth of aerobic heterotrophic bacteria. Also in the Schmutzdecke layer, a dominance of heterotrophic nitrifiers was found. The abundance of bacteria with nitrifying activity (AOB, comammox, HNAD) in the biomass of spongy fill placed in casings was 1.7 times lower than in foams without casings. In addition, anammox bacteria (unidentified Planctomycetes), found mainly in the sponge fill and Schmutzdecke of the three-layer filters, may have been responsible for NH4⁺-N removal exceeding 70%. In the case of the two-layer filter, the removal of this pollutant reached 92%. Burkholderia and Sphingopyxis were identified as the predominant denitrifying bacteria. The foam-filled filter in the casings showed an increase in o_Caldilineaceae, involved in nitrate removal as non-denitrifiers. Actinomycetes Pseudonocardia and Amycolatopsis, as well as Proteobacteria Devosia, Acinetobacter, and Bdellovibrio, were found to be involved in phosphorus removal in the waste PUR foams. Full article

Global population growth makes an increase in food production inevitable, and protein plays a vital role as an essential nutrient. However, as the proportion of land used for agriculture and animal protein production decreases, the search for sustainable, low-cost alternatives to proteins has become a research priority. Microalgae can synthesize a wide range of proteins, among which phycocyanin is of interest due to its unique biological activity. It has a complete amino acid profile, contains essential amino acids, and is a high-quality source of protein. Most of the existing studies have focused on single influencing factors, improved methods, or specific culture conditions for the synthesis of phycocyanin in microalgae and have not yet analyzed the culture conditions, influencing factors, and improved strategies for the synthesis of phycocyanin in microalgae in a systematic and integrated manner, and the studies lacked comprehensiveness and consistency. In this paper, the key factors, mechanisms of action, and improvement strategies affecting the accumulation of phycocyanin in microalgae are reviewed. The growth of microalgae under autotrophic, heterotrophic, and mixed culture conditions and their effects on phycocyanin synthesis were systematically described. The aim is to accelerate the application of phycocyanin in the food industry and alternative proteins by improving the production efficiency of microalgae, promoting their comprehensive utilization, and injecting a new impetus into the development of a sustainable protein industry. Full article