High Biomass Concentration Research Articles

High biomass content in epoxy vitrimers: a study on bio-based and reprocessable thermosets

High biomass content in epoxy vitrimers: a study on bio-based and reprocessable thermosets

Altered Lignin Accumulation in Sorghum Mutated in Silicon Uptake Transporter SbLsi1.

Sorghum [Sorghum bicolor (L.) Moench] has been receiving attention as a feedstock for lignocellulose biomass energy. During the combustion process, the ash containing silicon (Si) can be produced, which causes problems in furnace maintenance. Hence, lowering Si content in the plants is crucial. Nevertheless, limiting Si supply to crops is difficult in practice because Si is abundant in soil. Previously, a Si uptake transporter (SbLsi1) has been identified, and the Si-depleted mutant has also been generated in the model sorghum variety BTx623. In this study, we aim to investigate the change induced by the mutation of SbLsi1 on the accumulation and the structure of lignin in cell walls. Through chemical and NMR analyses, we demonstrated that the lsi1 mutation resulted in a significant increase in lignin accumulation levels as well as a significant reduction in Si content. At least some of the modification was induced by transcriptional changes, as suggested by the upregulation of phenylpropanoid biosynthesis-related genes in the mutant plants. These findings derived from the model variety would be useful for the future development of practical cultivars with high biomass and less Si content for bioenergy applications.

Evaluating a vertical greening system mesocosm for kitchen greywater treatment: Comparison among vegetation species in water consumption, biomass growth and pollutants uptake and removal

The escalating climate imbalance, coupled with rising water demands in rapidly expanding urban areas, is forcing scientists and policymakers to seek alternative strategies for efficient water resource management. Nature Based Solutions (NBS) are gaining prominence due to their ability to provide multiple ecosystem services. However, the quantification of benefits and drawbacks mediated by different vegetation species remains inadequate. In this study, we investigated the performance of a pot-based vertical greening system (VGS) designed to integrate the functions of green facades with those of treatment wetlands. The VGS was vegetated with Mentha aquatica L. (hereafter Mentha), Oenanthe javanica (Blume) DC. (hereafter Oenanthe) and Lysimachia nummularia L. (hereafter Lysimachia), and their respective effects on water balance and mass removal of common greywater pollutants were compared. Results indicated that VGS lines vegetated with Oenanthe and Mentha exhibited comparable pollutant removals. Oenanthe showed a preference for greywater that had already undergone partial treatment, while Mentha was not affected by any pollutant load in water removal −48.1 % of total inflow– and in nutrients uptake in aboveground biomass −14.3 % N and 7 % P– due to sustained and robust growth, outperforming Oenanthe and Lysimachia. This has suggested the potential use of Oenathe in combination with Mentha for enhanced performances, particularly given Oenanthe's rapid growth in the early season and high biomass and nitrogen content following initial greywater treatment.

Effect of biomass concentration in membrane bioreactor design on alpha factor for two large pilot systems: Case study of mechanical surface aeration and air insufflation system

In the literature, the studies on wastewater treatment process have shown a great interest in aeration system, most of them were performed on small pilot lab-scale. However, it still an important need to provide useful information aiming at reducing the operating costs and providing decision support to choose aeration devices. Considering that membrane bioreactors operating with high biomass concentrations up to 20–30 g of suspended solids (SS) per liter, the present study was carried out on a larger pilot lab-scale ( ± 500 l) of insufflation system and mechanical surface aeration on the same fresh sludge with concentration varying between 4.6 and 19.8 g/l. The comparison with literature data shows good correspondence with values obtained with our insufflation system but a great difference from values obtained in a mechanical system. In addition, this research provides a better insight on the calculation method that can be used to estimate the critical parameters of the oxygen transfer, and analyses the feasibility of air diffusion substitution by surface aeration system of Louvain La Neuve wastewater treatment plant of 13000 population equivalent. This extrapolation proved that a saving of ± 50,000 € per year can be achieved by choosing surface aeration rather than aeration by air insufflation.

Aboveground biomass in a post-mining forest succession in the Colombian Pacific

Introduction: Mining is one of the main drivers of deforestation of tropical forests. This activity affects the storage of aboveground biomass of these ecosystems; therefore, their ability to contribute to the mitigation of global climate change. Objective: To assess the influence of soil properties on the aboveground biomass storage of post-mining forests in the Colombian Pacific. Methods: Plots were established in areas post-mining and with different successional ages (12-15 years, 30-35 years, and mature forest). The aboveground biomass and physicochemical parameters of the soil were measured. Results: An aboveground biomass of 15.58 t ha-1, 35.17 t ha-1, and 178.32 t ha-1 was recorded at 12-15 years, 30-35 years, and mature forests, respectively. The species with the highest biomass content in post-mining forests were Cespedesia spathulata and Clidemia septuplinervia. The aboveground biomass was positively correlated with organic matter (OM), calcium (Ca), magnesium (Mg), CICE, total nitrogen (N), and silt. In contrast, the relationship was negative with sand, aluminum (Al), and potassium (K) content. It was evidenced that the relationship between aboveground biomass and soils differed in each successional age. When evaluating the changes of aboveground biomass and soils in the succession, it was observed that the aboveground biomass and total N increased with the recovery time. At the same time, the P and K decreased with succession. On the other hand, the contents of OM, Mg, Al, Ca, and CICE showed curvilinear tendencies since they increased in the first stages and then decreased in the advanced successional stages. Conclusions: Aboveground biomass increases with forest recovery time in the study area. This increase is influenced by the presence of two dominant species shared among the investigated ecosystems and by the soil's N, P, and K content.

Bioaugmentation with Clostridium pasteurianum for high-yield continuous bio-hydrogen production in a dynamic membrane bioreactor

This study demonstrated the feasibility of achieving high-yield continuous bio-H2 production through bioaugmentation with Clostridium pasteurianum. C. pasteurianum was introduced during the initial granulation stage in a dynamic membrane bioreactor (DMBR) inoculated with heat-treated digester sludge. Following bioaugmentation, the average hydrogen yield (HY) reached 3.07 ± 0.13 mol H2/mol hexoseconsumed, with a hydraulic retention time (HRT) of 2 h. This high-yield and high-rate hydrogen production performance was achieved alongside a high concentration of suspended and granular biomass as 21.02 ± 1.01 g VSS/L. The DM played a crucial role in prolonging the solid retention time of the suspended biomass to 12.15 h. C. pasteurianum emerged as the predominant species, constituting 92.3 % of the total bacterial population. This dominance significantly contributed to achieving the high HY, reaching 77 % of the theoretical maximum HY (4 mol H2/mol hexoseconsumed) by shifting the metabolic pathway from non-H2 production pathways to hydrogen-producing acetate. However, during further continuous operation, the hydrogen production pathway was gradually shifted towards the butyrate pathway, resulting in a decreased HY of 2.26 mol H2/mol hexoseconsumed along with the decreased population of C. pasteurianum. Additional bioaugmentation of C. pasteurianum during the maturational granulation stage did not impact the metabolic pathways or microbiome significantly, as the added strain was supposed to be washed out. This study provides insights into achieving high-yield continuous bio-H2 production through bioaugmentation with C. pasteurianum during the initial granulation stage. Further studies are necessary to sustain C. pasteurianum-dominated high HY with the acetate pathway during prolonged operation.

Impact of chlorine disinfection on intracellular and extracellular antimicrobial resistance genes in wastewater treatment and water reclamation

Wastewater treatment plants and water reclamation facilities are reservoirs of antimicrobial resistance genes (ARGs). These ARGs are not limited solely to intracellular DNA (inARGs) but include extracellular DNA (exARGs) present in wastewater. The release of exARGs from cells can be exacerbated by treatment processes, including chlorine disinfection, which disrupts bacterial cells. Given the potential for exARGs to drive horizontal gene transfer and contribute to the proliferation of antimicrobial resistance, it is imperative to recognize these fractions as emerging environmental pollutants. In this study, we conducted a comprehensive year-long assessment of both inARGs and exARGs, further differentiating between dissolved exARGs (Dis_exARGs) and exARGs adsorbed onto particulate matter (Ads_exARGs), within a full-scale wastewater treatment and water reclamation facility. The results revealed that Ads_exARGs comprised up to 30 % of the total ARGs in raw sewage with high biomass content. Generally, treatments at low and high doses of chlorine increased the abundance of Dis_exARGs and Ads_exARGs. The fate of ARG levels that varied depending on the type of ARGs suggested variations in the susceptibility of the host bacteria to chlorination. Moreover, co-occurrence of several potential opportunistic pathogenic bacteria and ARGs were observed. Therefore, we propose higher doses of chlorination as a prerequisite for the effective removal of inARGs and exARGs.

Cultivation of Limnospira maxima under extreme environmental conditions in Saudi Arabia: Salinity adaptation and scaling-up from laboratory culture to large-scale production

Limnospira maxima has been adapted to grow in high salinity and in an economically alternative medium using industrial-grade fertilizers under harsh environmental conditions in Saudi Arabia. A sequence of scaling-up processes, from the laboratory to large-scale open raceways, was conducted along with gradual adaptation to environmental stress (salinity, light, temperature, pH). High biomass concentration at harvest point and areal productivity were achieved during the harsh summer season (1.122 g L−1 and 60.35 g m−2 day−1, respectively). The average protein content was found to be above 40 % of dry weight. Changes in the color and morphological appearance of the L. maxima culture were observed after direct exposure to sunlight in the outdoor raceways. These results demonstrate a successful and robust adaptation method for algal cultivation at outdoor large-scale in harsh environment (desert conditions) and also prove the feasibility of using hypersaline seawater (42 g kg−1) as an algal growth medium.

UV-curing 3D printing of high-performance, recyclable, biobased photosensitive resin enabled by dual-crosslinking networks

UV-curing 3D printing technologies based on vat photopolymerization have gained increasing interest in rapidly manufacturing high-quality custom-designed objects. However, they are still challenged by the non-renewability of photosensitive resins in future large-scale applications. Herein, a high-performance, recyclable, biobased carboxyl-terminated unsaturated polyester is developed from itaconic acid and bio-diols, which involves the formation of dual-crosslinking networks, i.e., covalent crosslinking of unsaturated double bonds and non-covalent coordination interaction between terminal carboxyl and ZnCl2. Dual-crosslinking networks greatly increase tensile strength from 31 to 43 MPa by 40 %. More importantly, taking advantage of the dynamic reversibility of coordination and thermally-activated transesterification by ZnCl2, the universal problem, i.e. the anisotropic mechanical property in 3D printing caused by printing layers, can be effectively solved, attributed to reversible rearrangement and reassociation between printing layers. Moreover, after the 3D printing products are pulverized into microparticles, the powders can be thermally compressed into new materials with a 70 % recovery in tensile strength. In addition, these powders can also be used as reinforcing fillers to enhance the virgin resin, the optimum tensile strength and elastic modulus further increase to 52 MPa and 1019 MPa by 40 % with 1 wt% dosages. Therefore, this study is a pioneering pathway for the concurrent achievement of good mechanical properties (52 MPa) and high biomass content (96 wt%) for UV-curable 3D printing photosensitive resin.

Two-stage conversion of syngas and pyrolysis aqueous condensate into L-malate

Hybrid thermochemical–biological processes have the potential to enhance the carbon and energy recovery from organic waste. This work aimed to assess the carbon and energy recovery potential of multifunctional processes to simultaneously sequestrate syngas and detoxify pyrolysis aqueous condensate (PAC) for short-chain carboxylates production. To evaluate relevant process parameters for mixed culture co-fermentation of syngas and PAC, two identical reactors were run under mesophilic (37 °C) and thermophilic (55 °C) conditions at increasing PAC loading rates. Both the mesophilic and the thermophilic process recovered at least 50% of the energy in syngas and PAC into short-chain carboxylates. During the mesophilic syngas and PAC co-fermentation, methanogenesis was completely inhibited while acetate, ethanol and butyrate were the primary metabolites. Over 90% of the amplicon sequencing variants based on 16S rRNA were assigned to Clostridium sensu stricto 12. During the thermophilic process, on the other hand, Symbiobacteriales, Syntrophaceticus, Thermoanaerobacterium, Methanothermobacter and Methanosarcina likely played crucial roles in aromatics degradation and methanogenesis, respectively, while Moorella thermoacetica and Methanothermobacter marburgensis were the predominant carboxydotrophs in the thermophilic process. High biomass concentrations were necessary to maintain stable process operations at high PAC loads. In a second-stage reactor, Aspergillus oryzae converted acetate, propionate and butyrate from the first stage into L-malate, confirming the successful detoxification of PAC below inhibitory levels. The highest L-malate yield was 0.26 ± 2.2 molL-malate/molcarboxylates recorded for effluent from the mesophilic process at a PAC load of 4% v/v. The results highlight the potential of multifunctional reactors where anaerobic mixed cultures perform simultaneously diverse process roles, such as carbon fixation, wastewater detoxification and carboxylates intermediate production. The recovered energy in the form of intermediate carboxylates allows for their use as substrates in subsequent fermentative stages.

Hydrothermal liquefaction of swine wastewater-cultivated Chlorella sorokiniana SU-1 biomass for sustainable biofuel production

The environmental impact of fossil fuel consumption has shifted the focus of research toward biomass and bioenergy. Renewable biomass, such as microalgae, has several benefits, including growth in wastewater, sequestration of carbon dioxide, economic feasibility, and environmental friendliness. This study investigated the feasibility of using Chlorella sorokiniana SU-1 biomass cultivated on a swine-amended medium as a renewable feedstock to produce biocrude oil. Microalgal cultivation under optimal conditions of 50 % swine wastewater (SW), inoculum sizes of 1 g/L, CO2 concentration of 2 %, and light intensity of 300 μmol m−2 s−1 obtained a high biomass concentration (6.53 g/L), biochemical production (56.65 % carbohydrate content, 33.5 % protein content, and 4.35 % lipid content) and wastewater treatment performance [92.29 % chemical oxygen demand (COD) removal, 93.7 % total phosphorus (TP) removal, and 95.64 % ammonia removal]. Subsequently, hydrothermal liquefaction (HTL) of the obtained microalgal biomass achieved a 29.45 % biocrude oil yield with a composition of 34.3 % esters, 23.5 % hydrocarbons, 5.14 % aldehydes, 7.54 % furans, and 11.1 % phenolic derivatives, making it a promising choice for biofuel production. Thus, the findings confirmed that C. sorokiniana SU-1 could be effectively utilized for the phycoremediation of SW with simultaneous biomass production as a renewable feedstock for biocrude oil production.

Ultrasonication-induced metabolic pathway shifts and reduced electron carrier washout with biomass enhanced hydrogen yield in a continuous stirred tank reactor

Biohydrogen is pivotal for hydrogen economy, providing a renewable, carbon–neutral source of hydrogen from organic waste and biomass. It addresses environmental concerns and supports circular economy principles. However, challenges like managing metabolic pathways and dissolved hydrogen hinder attainment of higher hydrogen yields. This study explored the impact of organic loading rates (OLR) and ultrasonication on glucose fermentation by Clostridium pasteurianum for biohydrogen production.Results showed ultrasonication, particularly at 10 g/L.d OLR, increased hydrogen yield from 1.04 to 1.28 mol-H₂/mol-glucose. Higher OLR boosted biogas production, and at 10 g/L.d OLR, ultrasonication improved hydrogen purity from 46% to 53%, enhancing yield by 13%. C. pasteurianum shifted metabolic pathways under higher OLR, increasing lactate production to address redox imbalance. However, ultrasonication negatively affected lactate and acetate reutilisation, redirecting carbon flux from lactate to butyrate, increasing hydrogen yield.Combining ultrasonication and increased OLR enhanced glycolysis carbon flux by 14.5% and reduced biomass carbon flux by 10.5%. Hydrogen yield, influenced by glycolysis carbon flux, reached 82% under ultrasonication and increased OLR. Ultrasonication mitigated inhibitory effects on electron carrier molecule re-oxidation, emphasising the need to balance biomass, dissolved hydrogen concentration, and OLR for optimal hydrogen recovery.Despite decreased acetate/butyrate ratio and unchanged theoretical hydrogen production with ultrasonication, hydrogen yield increased. This likely resulted from reduced electron carrier molecule wastage with biomass, influenced by higher biomass concentration and ultrasonication. The study underscored preventing electron carrier molecule washout for higher hydrogen production and recommends using batch reactors over continuous stirred tank reactors in dark fermentation operations.

Investigating effective strategies for sustainable operation of a submerged anaerobic membrane bioreactor (SAnMBR) coupled with ceramic ultrafiltration membrane

This study presents a mechanistic approach to explore the key operational parameters governing the flux performance of an SAnMBR system coupled with a ceramic flat-sheet ultrafiltration membrane. Experiments were conducted at mixed liquor suspended solid (MLSS) concentrations of 12, 18, and 24 g/L using biogas sparging, backwashing, and a combination of both to investigate the most effective fouling mitigation strategy by exploring the fouling mechanism at a critical flux regime. To validate the experimental findings, a mathematical model was used to simulate the time-based variation of membrane effective pore radius (m), decrease in membrane porosity (%), thickness of cake layer (m), and membrane resistance (1/m). The study found that at a low biomass concentration, there was a sharp decline in the membrane pore radius leading to an increase in membrane resistance in the absence of any fouling mitigation strategies. However, by implementing these strategies individually and in combination, they maintained a higher pore radius and controlled the increase in membrane resistance even at high biomass concentrations. It was observed that biogas sparging outperformed the conventional backwashing strategy and the SAnMBR system exhibited superior performance attaining higher flux rates for prolonged duration. The advanced spectroscopic analysis confirmed the presence of a higher concentration of polysaccharides responsible for cake layer biofouling, and significant pore blocking due to inorganic foulants at high biomass concentrations. This suggests that the SAnMBR system must be operated at optimised biomass levels below the critical flux for sustained operation. Additionally, the key operational parameters identified using the mathematical model provide a precise assessment of SAnMBR performance, to improve its design efficiency for field applications.

β-Carotene production from sugarcane molasses by a newly isolated Rhodotorula toruloides L/24-26-1.

Production of carotenoids by yeast fermentation is an advantaged technology due to its easy scaling and safety. Nevertheless, carotenoid production needs an economic culture medium and other efficient yeast stains. The study aims to isolate and identify a yeast strain capable of producing carotenoids using a cost-effective substrate. A new strain was identified asRhodotorula toruloidesL/24-26-1, which can produce carotenoids at different pretreated and unpretreated sugarcane molasses concentrations (40 and 80g/L). The highest biomass concentration (18.6 ± 0.6g/L) was reached in the culture using 80g/L of hydrolyzed molasses. On the other hand, the carotenoid accumulation reached the maximum value using pretreated molasses at 40g/L (715.4 ± 15.1µg/g d.w). In this case, the β-carotene was 1.5 times higher than that on the control medium. The yeast growth in molasses was not correlated with carotenoid production. The most outstanding production of The DPPH, ABTS, and FRAP tests demonstrated the antioxidant activity of the obtained carotenogenic extracts. This research demonstrated theR. toruloidesL/24-26-1 strain biotechnological potential for carotenoid compounds. The yeast produces carotenoids with antioxidant activity in an inexpensive medium, such as sulfuric acid pretreated and unpretreated molasses.

Green Synthesis and Characterization of CaO Nanoparticles using Hen Eggshells and its Impact on Biomass Concentration, Chlorophyll-a and Lipid Content of Chlorella sp.

Biodegradable wastes e.g. the outer cover of a boiled hen egg generally haphazardly discarded by humans in different locations of the country and generates problems for the local creatures. Although different researchers reported different methods to utilize the waste through the nanotechnological approach. Here, green synthesis of calcium oxide (CaO) nanoparticles from the hen eggshells was carried out and characterized them by using X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray (EDX) analysis, Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectrophotometer (UV). Further application of the synthesized nanoparticles was done on Chlorella sp. to investigate the impact on algal growth, lipid and chlorophylls. Synthesized CaO nanoparticles were applied in different concentration (0, 10, 20 and 30 mg L–1) and readings were monitored for 20 days. The highest biomass concentration 242.56 mg L–1 was achieved for the nanoparticle concentration of 20 mg L–1 and the lipid content increased up to 35.71% in 20 mg L–1. These results pave the way for enhanced algal biofuel production.

Influence of Biogenic Material Content on the Biodegradability of Styrene-Butadiene Composites with Incorporated Chlorella vulgaris Biomass.

Bio-fillers are intensively studied for advanced polymer composite circular design and production. In this context, the algal biomass may be considered an important and relatively low-cost resource, when harvested as a by-product from wastewater treatment plants. The biomass of the algal species Chlorella vulgaris is frequently used in this type of environmental process, and its macro constituents' composition ranges from around 15-25% carbohydrates, 10-20% lipids, and 50-60% proteins. Poly (styrene-butadiene-styrene) (SBS) copolymers have a matrix composed of glassy polystyrene domains connected by flexible polybutadiene segments. Although the physical-mechanical properties of SBS copolymers recommend them for many industrial applications, they have the drawback of low biodegradability. This study aimed to assess the aerobic biodegradability of polymer composites by integrating biomass from Chlorella vulgaris at varying mass percentages of 5, 10, and 20% into SBS copolymer composites. Biodegradation tests were conducted under industrial composting conditions (58 °C and 50% relative humidity) for 180 days. The biodegradability of materials was evaluated by measuring the CO2 produced in each vessel during the study period. Potential correlations between the amount of carbon dioxide released and the percentage of biomass added to the polymer matrix were examined. Structural and morphological changes were assessed using Fourier Transform infrared spectroscopy (FTIR), thermal analysis (DSC), and scanning electron microscopy (SEM). Physical and chemical testing revealed a decrease in sample density after the industrial composting test, along with noticeable changes in melt flow index (MFI). The observed physical and chemical changes, coupled with FTIR, SEM, and DSC data, indicate increased cross-linking and higher porosity in biodegraded polymer structures with higher biomass content. This behavior is likely due to the formation of cross-linked connections between polymer chains and polypeptide chains resulting from protein degradation, enhancing connections between polystyrene units facilitated by peptide bonds with the benzene units of the styrene blocks within the polymer matrix.

Upcycling nitrogen and curbing greenhouse gas emissions from wastewater through H2-driven assimilatory mixotrophic metabolism

Biological nitrogen assimilation is an emerging technique for the removal and upcycling of nitrogen from wastewater in the form of microbial protein (MP). For this purpose, a mixed hydrogen-oxidizing bacteria (HOB) culture capable of growing mixotrophically was evaluated for the treatment of synthetic and real wastewater under different carbon-to-nitrogen (C/N) ratios. The same mixed HOB culture was grown under heterotrophic conditions to compare treatment and process performances in terms of ammonium nitrogen (N-NH4+) removal and assimilation, chemical oxygen demand (COD) removal, CO2 release, biomass concentration, yield and protein content. Under mixotrophic conditions, the highest biomass concentration was 342.5 mg VSS∙L−1, doubling that obtained under heterotrophic conditions (161.2 mg VSS∙L−1). Discharge limits for both COD and total N were met under mixotrophic conditions, with nitrogen removal and assimilation into protein-rich biomass achieving up to 99 %. On the contrary, under heterotrophic conditions, the high content of residual nitrogen as nitrite (up to 26 mg∙L−1 of N-NO2−) did not allow to meet discharge limits for total N. The mixed HOB culture gave promising results in terms of biomass yield (0.32 g VSS·g CODH2+acetate−1) and protein content (up to 56 % of VSS) when grown mixotrophically. Under heterotrophic conditions, instead, the biomass yield (0.25 g VSS·g CODacetate−1) and protein content (35 %) were substantially lower. This study suggests that the H2-driven assimilatory mixotrophic metabolism can be successfully applied for wastewater treatment to produce effluents that meet discharge limits while mitigating greenhouse gas emissions (CO2 and N2O) and upcycling nitrogen into MP.

Transcriptome and metabolome analysis reveals the salt stress-response mechanism in desert isolated Chlorella sp. DT025

Understanding salt stress-response mechanisms is beneficial for biodiesel production using microalgae. Herein, using physiological and multi-omics analyses, we revealed substance changes and the salt-stress response of Chlorella sp. DT025, isolated from a desert salt marsh. Using 15–30 g/L NaCl, high biomass (4.1–2.6 g/L) and high lipid content (45–65 %) were obtained. Under salt stress, the levels of chlorophyll synthesis-, photosynthesis-, Calvin cycle-, and starch synthesis-related differentially expressed genes (DEGs) were downregulated, while the contents of chlorophyll, most amino acids and nucleotides were decreased. Moreover, the levels of TCA cycle-, fatty acid (FA) synthesis and degradation-, glycerophospholipid metabolism-, nitrogen metabolism-, proline synthesis-, and antioxidant metabolism-related DEGs were upregulated, increasing FAs (major 16- and 18- carbon FAs), phosphatidylglycerol, lysophosphatidylglycerol, digalactosyldiacylglycerol, proline, catalase, and superoxide. These results reveal the molecular basis of salt tolerance in DT025 and suggest that it exhibits active metabolism using lipids as substances for energy storage and release under salt stress.

Influence of drinking water biofilm microbiome on water quality: Insights from a real-scale distribution system

Biofilms, constituting over 95 % of the biomass in drinking water distribution systems, form an ecosystem impacting both the aesthetic and microbiological quality of water. This study investigates the microbiome of biofilms within a real-scale drinking water distribution system in eastern Spain, utilizing amplicon-based metagenomics. Forty-one biofilm samples underwent processing and sequencing to analyze both bacterial and eukaryotic microbiomes, with an assessment of active biomass. Genus-level analysis revealed considerable heterogeneity, with Desulfovibrio, Ralstonia, Bradyrhizobium, Methylocystis, and Bacillus identified as predominant genera. Notably, bacteria associated with corrosion processes, including Desulfovibrio, Sulfuricella, Hyphomicrobium, and Methylobacterium, were prevalent. Potentially pathogenic bacteria such as Helicobacter, Pseudomonas, and Legionella were also detected. Among protozoa, Opisthokonta and Archaeplastida were the most abundant groups in biofilm samples, with potential pathogenic eukaryotes (Acanthamoeba, Naegleria, Blastocystis) identified. Interestingly, no direct correlation between microbiota composition and pipe materials was observed. The study suggests that the usual concentration of free chlorine in bulk water proved insufficient to prevent the presence of undesirable bacteria and protozoa in biofilms, which exhibited a high concentration of active biomass.

Dry matter distribution of banderita grass [Bouteloua curtipendula (Michx.) Torr.] at different plant strata

Objective: To evaluate the dry matter distribution of banderita grass [Bouteloua curtipendula (Michx.) Torr.] in different plant strata.
 Design/Methodology/Approach: A randomized block experimental design with five repetitions was used for the experiment. Each repetition consisted of three plants which were evaluated at different days after sowing (DAS), in three different plant strata: basal stratum (BS), middle stratum (MS), and upper or apical stratum (AS). The following variables were evaluated: dry matter yield (DMY), morphological composition (MC), leaf area (LA), plant height (PH), leaf:stem ratio (L:SR), and aerial part:root ratio (Ap:rR). An analysis of variance was performed, using the PROC GLM procedure of the SAS software; in addition, a comparison of means was carried out using Tukey’s test (α<0.05).
 Results: SB made a greater contribution to DMY at 50 DAS, with a 16 g DMY plant-1 average, followed by MS, with 9 g DM plant-1, and AS with 3 g plant-1. The MC (g) in the BS registered that the stem made a greater contribution than the rest of the components (average: 12.3 g plant-1), while leaves from the MS and AS made the greatest contribution (2.6 g plant-1) up to 64 DAS. However, they were surpassed by the stem in the MS and by the inflorescence in the AS. In addition, BS registered the highest LA (173.4 cm2). The largest PH was recorded at 120 DAS (96 cm). The highest L:SR ratio reached 1.10 at 50 DAS, while Ap:rR recorded 3.82 at 92 DAS.
 Study Limitations/Implications: The experiment was carried out under greenhouse conditions. Therefore, any extrapolation or comparison with field conditions should be done with caution.
 Findings/Conclusions: The basal and middle part of a banderita grass (Bouteloua curtipendula) plant contains the highest forage accumulation (mainly in the leaves and the stem), while the highest biomass content in the apical part is produced by the inflorescence.