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At least 19 recordsLinked to original sources

PubMed2026

Biomass burning contributions to Mexico City's atmospheric CO2 estimated using a multi-isotope approach.

Fossil fuel combustion dominates anthropogenic emissions worldwide; however, special attention should be addressed to biomass burning, since it is an increasingly important contributor under warmer, drier fire-weather conditions exacerbated by climate change. These emissions could impact the atmospheric composition of heavily urbanized environments. To assess the influence of biomass burning, along with fossil fuels combustion and soil and plant respiration on Mexico City's atmospheric composition, we conducted a year-long (December 2023-December 2024) isotopic monitoring of atmospheric CO2, combining radiocarbon (Δ14C), CO2 stable isotopes (δ13C, δ18O), and CO/CO2 ratios. Once defined the isotopic signatures and the characteristic CO/CO2 that describe the sources, we performed Monte Carlo simulations under two tracer modalities (Δ14C + CO/CO2 and Δ14C + CO2 stable isotopes) for source apportionment. Results show that during the dry season, particularly in March-April, atmospheric Δ14C values approached and overlapped background levels despite Mexico City's fossil-fuel dominance, indicating enhanced non-fossil inputs. Moreover, backward HYSPLIT trajectories supported that these elevated Δ14C values coincided with regional wildfire activity. Monte Carlo results attributed up to ∼34 %-60 % of local CO2 to biomass burning in April, followed by March with contributions of ∼31 %-49 %. Since these biomass burning figures contrast with the official emissions inventory of Mexico City metropolitan area, which assigns <1 % of total CO2 emissions to biomass burning, this study could exhibit the emissions inventory underestimation of this source, and thus, the need to reassess and incorporate top-down isotopic constraints in fire-affected urban regions.

Mexico↗

PubMed2026

Integration of domestic wastewater and native Tetradesmus obliquus for bioremediation and production of biomass rich in protein and polyunsaturated fatty acids.

The large-scale deployment of microalgae-based bioprocesses is often limited by high freshwater and nutrient demands. Domestic wastewater represents a sustainable alternative, enabling simultaneous pollutant removal and biomass production. In this study, a native strain of Tetradesmus obliquus, isolated in southern Brazil, was cultivated in raw domestic wastewater (RDW) and primary-treated domestic wastewater (TDW) at three initial inoculum densities (10%, 20%, and 30% v/v) for 14 days. Tetradesmus obliquus in TDW inoculated at 10% (v/v) removed 62.46% of ammonium and 98.56% of phosphate, simultaneously exhibiting the highest specific growth rate (0.16 d⁻1) and the highest biomass productivity (42.54 mg L⁻1 d⁻1). Iron and manganese concentrations decreased significantly with a native strain in TDW, indicating effective removal of them under the evaluated conditions. RDW was associated with higher carbohydrate accumulation (32.68%) and pigment production, whereas TDW was associated with higher protein content (45.83%) and a lipid fraction with a high relative proportion of polyunsaturated fatty acids (72.70-78.90%), primarily represented by α-linolenic and linoleic acids. The combined assessment of wastewater condition and initial inoculum density revealed distinct effects on the cultivation system. These aspects influence the biochemical composition of biomass, initial inoculum density, nutrient removal, specific growth rate, and biomass productivity. Thus, the present study supports the potential to integrate domestic wastewater treatment with the cultivation of a native Tetradesmus obliquus strain and indicates that, under the evaluated conditions, both the wastewater treatment conditions and the initial inoculum density influenced bioremediation performance and the biochemical composition of biomass.

Biochemical composition↗

PubMedDate not supplied

[Short-term changes in the biomass of fungi and bacteria in soddy-podzolic soil].

Short-term (diurnal or daily) changes in fungal and bacterial biomass were studied using direct count. Diurnal changes in microbial biomass were found to be unreliable. Daily observations have shown that the length of fungal mycelium can change 3--4-fold within 10--30 days, and the number of bacteria, 2--3-fold, the frequency and amplitude of changes depending on the season. Fungal biomass was found to be greater than bacterial biomass by a factor of dozens; that is why, while estimating the biomass of soil fungi, other indices of the biological activity of soil (DNA content, enzymic activity, respiration, etc.) must be taken into account.

Bacteria↗

PubMed2026

Multistrategy metabolic engineering of Talaromyces pinophilus for α-amylase production from lignocellulosic biomass.

Filamentous fungi are important hosts for industrial enzyme production. Growing demand for α-amylase has increased reliance on food-derived carbon substrates, necessitating fungal strains that efficiently utilize nongrain biomass. In this study, Talaromyces pinophilus Y117 was metabolically engineered to produce α-amylase from lignocellulosic biomass. A strong cellobiohydrolase I gene (cbh1) promoter (Pcbh1Tru) was identified to drive expression. Multiple rounds of multilocus integration of the α-amylase gene were performed using homologous multicopy genomic sequences as recombination arms with a Cre/loxP-based recyclable selection system, yielding the multicopy strain Tp4, which achieved 4124.5 U/mL α-amylase activity in shake-flask fermentation with corncob powder as the sole carbon source. To minimize enzyme degradation, the protease gene 8538 was deleted using the Cre/lox2272 system, generating Tp4Δp. This strain showed a 50% increase in shake-flask α-amylase activity (6208.4 U/mL). In 3-L bioreactor cultivation, Tp4Δp exhibited excellent production performance, achieving 26 712.2 U/mL α-amylase activity. When corncob powder was used as the sole substrate, the cellulose and hemicellulose degradation rates reached 90.00% and 70.01%, respectively, and the enzyme yield reached 213 697.5 U per gram of corncob powder. This engineered strain demonstrates strong potential for industrial applications. The synthesis-degradation synergistic optimization strategy provides a practical approach for engineering filamentous fungal cell factories to produce enzymes directly from lignocellulosic biomass. One sentence summary Metabolic engineering of Talaromyces pinophilus through promoter optimization, multicopy integration, and protease deletion enables efficient α-amylase production from lignocellulosic biomass, achieving 26 712 U/mL in bioreactor fermentation.

Talaromyces↗

PubMedDate not supplied

[Total number and biomass of microorganisms in the depths of the Black Sea].

The total number and biomass of microorganisms, as well as the ratio between their main morphological forms, were determined by capillary microscopy in 22 water samples taken at various depths from the surface to 1500 m in the eastern part of the Black Sea. The total number of microorganisms was several times higher at depths over 150 m in the hydrogen sulfide zone than in the oxygen zone (0--150 m), whereas the biomass was greater by an order of magnitude. The number of microorganisms varied within a range of 1.4--12.4X10(3) cells/ml in the oxygen zone and 3.8--34.9X10(3) cells/ml in the hydrogen sulfide zone, whereas the biomass was 0.9--6.9 mg/m3 and 10.8--55.6 mg/m3, respectively. The bulk of the microbial biomass in the hydrogen sulfide zone was constituted by peculiar filamentous forms described for the first time by Lebedeva (1953, 1963) and, apparently, participating in sulfur turnover.

Bacteria↗

PubMed1979

Effect of the nonilluminated part of suspension on biomass production in an algal reactor.

The production of algal biomass in the illuminated and nonilluminated part of the suspension in an algal reactor was analyzed with regard to the biological inertia of the algae. The calculations indicate a considerable effect of nonilluminated part of the reactor on algal biomass production. The intensity of suspension stirring affects biomass production only slightly.

Adaptation, Physiological↗

PubMedDate not supplied

[Specific gravity of the dried biomass of pure bacterial cultures].

The weight of wet and dry biomass taken from colonies after growth on MPA was determined in pure bacterial cultures of Pseudomonas denitrificans and Brevibacterium imperiale, and the number and dimensions of bacterial cells in dry preparations of the same colonies were measured by means of membrane filters. The average specific weight of dry biomass was found to be 1.68 and 1.62. In calculating the weight of bacterial biomass in pure cultures and natural cenoses, its volume should be assayed taking into account the number and dimensions of the cells in dry preparations on membrane filters and multiplying by a coefficient 1.6.

Bacteria↗

PubMedDate not supplied

[Total number, biomass and production of bacteria in the water of the subtropical and equatorial-tropical regions of the Pacific Ocean].

The total number and biomass of bacteria were determined by capillary microscopy in 168 samples of water taken from different horizons (0-5,000 m) in the subtropic and equatorial-tropic regions of the central part of the Pacific Ocean (135 degrees and 150 degrees w. long) and the western half of the Indian Ocean (65 degrees e. long). In most cases, 1 ml of water contained dozens and hundreds of thousands of the cells whose biomass was several or dozens milligrams per 1 m3. Layers with a high content of bacteria were encountered not only in the surface zone but also at large depths. In the euphotic layer (0-200 m), the mean value of the bacterial biomass was similar to that of phytoplankton in mesotrophic waters of tropic divergences and subpolar zones. Vertical distribution of the total number of the microorganisms was found to be similar to distribution of saprophytic bacteria studied earlier.

Bacteria↗

PubMed2026

ZrO₂@C-based colorimetric/photothermal dual-mode immunosensor coupled with a novel monoclonal antibody for quantification of Aspergillus ochraceus biomass.

Aspergillus ochraceus contaminates agricultural products and produces nephrotoxic, carcinogenic ochratoxin A (OTA), posing severe food safety hazards. A dual-signal lateral flow immunochromatographic assay (dLFIA) based on ZrO₂@C nanoprobes was established for quantitative detection of A. ochraceus biomass. A novel monoclonal antibody (mAb 4B4) was prepared as the capture antibody to immobilize A. ochraceus mycelial lysate antigen on the test line, and a rabbit polyclonal antibody (pAb G2801) as the detection antibody to modify ZrO₂@C composites (synthesized via UiO-66 pyrolysis) into 200 nm colorimetric/photothermal nanoprobes. This dLFIA achieved limits of detection of 0.164 μg/mL (colorimetric) and 0.517 μg/mL (photothermal). This efficient and reliable method allows quantitative analysis of A. ochraceus biomass, which is suitable for routine monitoring of fungal contamination in agro-food matrices.

Antibodies, Monoclonal↗

PubMed2026

Inducible flocculation in Komagataella phaffii enables enhanced biomass separation for biopharmaceutical production.

Biomass separation represents a critical bottleneck in Komagataella phaffii-based biopharmaceutical processes, as typically high cell densities of 40 - 50 % create significant operational, technical and economic challenges for harvest operations. Yeast cell aggregation (flocculation) provides a solution to accelerate cell sedimentation by increasing particle size, thus allowing to improve biomass-supernatant separation efficiency during both natural gravity settling and (continuous) centrifugation operations. This study demonstrates successful engineering of K. phaffii strains with an inducible flocculation phenotype using CRISPR/Cas9-based genome editing to integrate the Saccharomyces cerevisiae FLO1 (ScFLO1) gene under control of various regulatory elements, including methanol-inducible and derepressible promoters. Flocculation strength could be enhanced by implementing transcriptional positive feedback circuits based on the methanol-inducible AOX1 promoter. To address methanol-free production requirements, we developed alternative systems to retrofit PAOX1-based ScFLO1 expression and exploited the derepressible PDF promoter, offering broader compatibility with biopharmaceutical manufacturing facilities. Flocculating cells cultivated in a bioreactor demonstrated significantly improved sedimentation behavior, with considerably lower supernatant turbidity after short low-speed centrifugation or gravity sedimentation compared to non-flocculating controls. Crucially, cell flocculation had no negative impact on product amount and quality when expressing a multivalent NANOBODY® VHH molecule with pharmaceutical relevance. Thus, this work establishes the first genetically engineered flocculation system in K. phaffii compatible with recombinant protein production, providing the basis for an innovative approach to streamline harvest operations in biopharmaceutical processes.

Flocculation↗

PubMed2025

Epitranscriptomic reprogramming in response to low CO2 stress and m6A engineering to enhance biomass production in Nannochloropsis oceanica.

N6-adenine methylation (m6A) as an epitranscriptomic mark is the most abundant modification in eukaryotic RNA and plays a dynamically regulated role. However, m6A dynamics, deposition and engineering in microalgae remain largely unknown. Here, in Nannochloropsis oceanica, the dynamic alterations and reprogramming in m6A RNA modifications after the shift from high to low CO2 conditions were first investigated using methylated RNA immunoprecipitation sequencing. The m6A peaks in N. oceanica were mainly enriched in 3'UTR. A positive association between m6A abundance and mRNA transcription of CO2-responsive genes was observed; moreover, N. oceanica cells adopted versatile strategies in a dynamic reprogramming of m6A in response to low CO2 stress. Secondly, knockout of two putative m6A methylases including NoMTA (NO04G02990) and NoMTB (NO07G02450) by genome editing induced methylation reprogramming, which was associated with expression changes of low-CO2 responsive genes such as carbon/nitrogen metabolism, and photorespiration genes that underlie reductions in growth and biomass. Lastly, m6A modification reprogramming was first engineered to increase low-CO2 stress tolerance and biomass productivity by the CRISPR/dCas13 system combined with MTA and NoMTB under low CO2 in N. oceanica. Therefore, these strides would pave the way for microalgal epigenetics and future industrial applications.

Microalgae↗

PubMed1975

Biological value of the biomass and protein isolates from different yeasts.

The microbiological analysis with the test-organism Tetrahymena pyriformis W can be used successfully to measure the relative nutritive value of the biomass and protein isolates from different yeasts for screening the groups of micro-organisms to choose those of the desired quality. In general, this method is rapid, comparatively cheap and gives the possibility to test large numbers of samples simultaneously. According to the literature and our own results, the relative nutritive value, the percentage of absorbed "N", retained by test-organism and used for its growth and multiplication expressed as cell count and given in relation to a standard protein (casein) is generally in a good agreement with results obtained with animals. This microbiological method is promising for investigating the influence of certain technological operations on the quality of protein. The investigation has been performed by the use of Baker's yeast Saccharomyces cerevisiae, of fodder yeast Candida, grown on oil hydrocarbons and on wood hydrolysates, yeasts Hansenula and Mycoderma, grown on a medium containing ethanol as the sole carbon source. The best results were obtained with the yeast grown on the ethanol-containing medium. The biological value of the biomass of yeast Hansenula is 91% and of protein isolate 96% as related to casein as the standard protein.

Amino Acids↗

PubMed1978

Biomass yields of Chlorella from iron (Yx/Fe) in iron-limited batch cultures.

The maximum biomass in iron-limited photosynthetic batch cultures of chlorella increased as the logarithm of the iron concentration. The growth yield from iron (UxFe) showed a marked inverse relation to the specific growth rate. The maximum biomass yield, g dry biomass/g iron consumed, was 7.5 X 10(3) with specific growth rate 0.108h-1; the minimum was 0.79 X 10(3) with specific growth rate 0.145 h-1. The maximum specific growth rate in the exponential phase of Fe limited cultures varied as the initial Fe concentration. Fe-limited growth made the cells adhere to a glass surface.

Chlorella↗

PubMed1978

Polygalacturonase, biomass and ascospore production by Byssochlamys fulva. II. Effects of sugars found in fruits.

Polygalacturonase, biomass, and ascospore production by four strains of Byssochlamys fulva cultured in laboratory media supplemented with glucose, sucrose, or fructose was studied over a 20-day incubation period at 30 degrees C. The production of polygalacturonase was variable, but most activity was detected between 4 and 8 days in 1% sugar media at an initial pH of 4 or 5. The rate of biomass production was retarded early in the incubation period in media initially at pH 3 or 4 as compared to pH 5, but the amount of growth was about the same in media containing the test sugars after 20 days. Large numbers of ascospores were produced between 8 and 10 days in media containing 5% sugar initially at pH 5 and 4. Production of ascospores was retarded at pH 3 in media containing 5% sugar as compared to media initially at pH 5 and 4.

Ascomycota↗

PubMed1976

Influence of specific growth rate on biomass yield, productivity, and compostion of Candida utilis in batch and continuous culture.

Candida utilis was grown in batch and continuous culture on prickly pear juice as sole carbon and energy source. In batch culture the maximum specific growth rate (mum) and the substrate yield coefficient (Yps) varied according to sugar concentration. When the fermentation was carried out with 1% sugar, mum and Ys were 0.47/h and 42.6%, respectively. The best yields occurred in a chemostat at the pH range of 3.5 to 4.5 and temperature of 30 C. A beneficial effect on Ys was observed when the dilution rate (D) was increased. At a D of 0.55/h, the productivity was 2.38 g/liter per h. The maintenance coefficient attained a value of 0.09 g of sugar/g of biomass per h. Increases of D produced higher protein contents of the biomass. The information obtained indicates that protein production with Candida utilis, using prickly pear juice, should be carried out a high dilution rates where the Ys and protein content of the cell mass are also higher.

Candida↗

PubMed1977

Determination of bacterial number and biomass in the marine environment.

Three techniques for the measurement of bacterial numbers and biomass in the marine environment are described. Two are direct methods for counting bacteria. The first employs an epifluorescence microscope to view bacteria that have been concentrated on membrane filters and stained with acridine orange. The second uses a transmission electron microscope for observing replicas of bacteria that are concentrated on membrane filters. The other technique uses Limulus amebocyte lysate, an aqueous extract from the amebocytes of the horseshoe crab, Limulus polyphemus, to quantitate lipopolysaccharide (LPS) in seawater samples. The biomass of gram-negative (LPS containing) bacteria was shown to be related to the LPS content of the samples. A factor of 6.35 was determined for converting LPS to bacterial carbon.

Bacteria↗

PubMedDate not supplied

[Growth and biomass accumulation by several strains of Pseudomonas on nutrient with ethanol].

The capacity to grow in a mineral medium with ethanol as a sole carbon source was studied in 147 Pseudomonas strains. All of the strains can grow in this medium. The biomass accumulation in the mineral medium with ethanol (1%) and maize extract (0.2%) is 2.5--5.0 times higher than without the latter. Strains which accumulate up to 3.5 g of dry biomass per litre (containing 62--66% of protein and 5.3% of nucleic acids) in the mineral medium with ethanol (1%) and maize extract (0.2%) have been selected. The quantitative content of essential amino acids satisfies the requirements while that of lysine, threonine, valine and leucine is twice as high.

Amino Acids↗

PubMedDate not supplied

[Comparison of different methods for measuring nucleic acids and protein in the biomass, half-products and preparations of E. coli and yeast].

In the E. coli biomass, half-products and RNA preparations a comparative measurement of nucleic acids and protein was carried out using different methods. As a result, the following methods can be recommended: to assay RNA in the biomass--spectrophotometry, to determine RNA in half-products and preparations--the phosphate method, to assess DNA--the diphenyl amine method, and to measure protein--according to Lowry. The same methods can be recommended to estimate RNA from baker's yeast.

Bacterial Proteins↗