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PubMed2002

Diffusion of sulfuric acid within lignocellulosic biomass particles and its impact on dilute-acid pretreatment.

Intra-particle diffusion of sulfuric acid into sugarcane bagasse, corn stover, rice straw and yellow poplar was investigated to determine the effective diffusivity of sulfuric acid within the porous biomass structure. Diffusion experiments were conducted over 25-75 degrees C for two different biomass sizes using dynamic diffusion test cells. Diffusivities of sulfuric acid in agricultural residues were significantly higher than those of hard wood. Diffusivity data for each biomass were fitted into the Arrhenius equation for extrapolation to higher temperatures. The diffusivity data were subsequently incorporated into a theoretical model to determine acid profile within the biomass matrix. The modeling results indicate that intra-particle diffusion of acid influences the rate of dilute-acid pretreatment if unground biomass feedstock is used under normal pretreatment conditions. A criterion was set up to determine the critical biomass size at which the intra-particle acid diffusion becomes a rate-influencing factor for a given pretreatment condition.

Acids↗

PubMed2002

Biosorption of phenol from an aqueous solution by Aspergillus niger biomass.

Phenols in trace quantities are usually present in the treated effluent of many wastewater-treatment plants. Phenol contamination of drinking water even at 1 microg/l concentration can cause significant taste and odor problems. This study investigates the use of non-viable pretreated cells of Aspergillus niger to remove phenol from an aqueous solution. Five types of non-viable pretreated A. niger biomass powders were used as a biosorbent to remove phenol present in an aqueous solution at a concentration of 1,000 microg/l. Sulfuric acid-treated non-viable biomass powder, which was the most effective, was used as a biosorbent in a further study. The maximum removal of phenol was observed at an initial pH of 5.1 for the sulfuric acid-treated biomass. The adsorption of phenol by pretreated A. niger biomass was best described by the Brunauer Emmet Teller model. Desorption of phenol using distilled deionized water was found to be approximately 5% suggesting a strong biosorption by the biomass. Sulfuric acid-treated biomass beads developed through immobilization in polysulphone were used in a column study. Approximately 66% of phenol was removed in the column operated at an initial pH of 5.1 and an initial concentration of 1,000 microg/l of phenol.

Adsorption↗

PubMed1987

Relationships between Biovolume and Biomass of Naturally Derived Marine Bacterioplankton.

Microscopic estimation of bacterial biomass requires determination of both biovolume and biovolume-to-biomass conversion. Both steps have uncertainty when applied to the very small bacteria typically found in natural seawater. In the present study, natural bacterioplankton assemblages were freshly collected, passed through 0.6-mum-pore-size Nuclepore filters to remove larger particulate materials, and diluted for growth in 0.22-mum-pore-size Millipore filter-sterilized unenriched seawater. This provided cells comparable in size and morphology to those in natural seawater, but the cultures were free of the interfering particulate detritus naturally present. Cells were collected on glass-fiber GF/F filters, and biovolumes were corrected for cells passing these filters; C and N were measured with a CHN analyzer. Our criteria for size measurement by epifluorescence photomicrography were confirmed with fluorescent microspheres of known diameters. Surprisingly, in six cultures with average per-cell biovolumes ranging from 0.036 to 0.073 mum, the average per-cell carbon biomass was relatively constant at 20 +/- 0.08 fg of C (mean +/- standard error of the mean). The biovolume-to-biomass conversion factor averaged 0.38 +/- 0.05 g of C cm, which is about three times higher than the value previously estimated from Escherichia coli, and decreased with increasing cell volume. The C:N ratio was 3.7 +/- 0.2. We conclude that natural marine bacterial biomass and production may be higher than was previously thought and that variations in bacterial size may not reflect variations in biomass per cell.

Journal Article↗

PubMed2006

Platelet activation, upregulation of CD11b/ CD18 expression on leukocytes and increase in circulating leukocyte-platelet aggregates in Indian women chronically exposed to biomass smoke.

The majority of households in rural India still rely on unprocessed solid biomass for domestic energy. The aim of this study was to investigate whether chronic exposure to biomass smoke causes activation of leukocytes and the formation of leukocyte-platelet aggregates. We conducted flow cytometric analysis of beta2 Mac-1 integrin (CD11b/CD18) expression on polymorphonuclear leukocytes (PMN) and monocytes, and P-selectin (CD62P) expression on the platelets of 165 women from eastern India, who cook solely with wood, dung and agricultural wastes, and 155 age- and socio-economic condition-matched control subjects, who used relatively cleaner fuel, liquefied petroleum gas (LPG). Leukocyte-platelet aggregates were defined as CD11b-positive PMN and monocytes co-expressing platelet-specific markers CD41 or CD62P. A significant increase in leukocyte-platelet aggregates was found in women who used biomass as cooking fuel. In addition, they showed increased surface expression of CD11b/CD18 in circulating PMN and monocytes and CD62P expression on platelets. The mean fluorescence intensity (MFI) of CD11b on the surface of circulating monocytes and PMN of biomass users increased by 50 and 68%, respectively. Similarly, a 62 and 48% increase in MFI was observed in CD18 expression on the surface of these cells in biomass users. The results show that chronic biomass smoke exposure activates circulating platelets, PMN and monocytes, and increases the number of leukocyte-platelet aggregates, which are considered a risk factor for thrombosis.

Adult↗

PubMed2002

Radiation Use Efficiency and Biomass Production in Soybean at Different Plant Population Densities.

As population density (POP) increases in a soybean [Glycine max (L.) Merr.] crop, maximum light interception (LI) occurs earlier in the season. Earlier canopy closure would be expected to increase the cumulative radiation intercepted. We hypothesized that if radiation use efficiency (RUE) was constant across a range of population densities in a nonstressful environment, then increasing POP would increase biomass at the end of the season. To test this hypothesis, we evaluated the response of total biomass produced during the season to cumulative intercepted photosynthetically active radiation (PAR) in field experiments at Fayetteville, AR, with soybean cultivars selected from Maturity Groups (MGs) 00 to IV. Additionally, from field experiments at Keiser, AR, with MG IV soybean cultivars, we assessed the response of RUE to POP. At both locations with MG IV cultivars, a late sowing date shortened the life cycle of the crop by 13 to 25 d compared with an early sowing date, resulting in less PAR accumulated. Similarly, early maturing cultivars had less time for PAR and biomass accumulation relative to later maturing cultivars. At Keiser, in three of the four environments, RUE decreased linearly by 26 to 30% as the POP increased from 7 to 135 plants m(-2). Final biomass at the end of the season, as a function of PAR accumulated from emergence to the full-seed-size stage of development, responded linearly to intercepted PAR up to approximately 400 MJ m(-2). Above 400 MJ m(-2), the response was curvilinear with little increases in biomass >700 MJ m(-2). Our data clearly indicate that RUE decreased as POP increased and that maximum biomass production in these environments was not limited by intercepted PAR.

Journal Article↗

PubMed2004

[Dynamics of microbial biomass N in different fertilized black soil and its related factors].

This paper studied the dynamics of microbial biomass N in a black soil long-term fertilized with farmyard manure (M2 and M4) and chemical fertilizer (NPK) during crop growth season. The results showed that the soil microbial biomass N was 25.52-239.12 mg x kg(-1) in M4, 10.40-94.31 mg x kg(-1) in M2, 6.27-87.04 mg x kg(-1) in NPK, and 9.15-69.81 mg x kg(-1) in CK. In same treatment, the highest value was 7-14 times higher than the lowest value. Treatments NPK and M2 had the highest value of microbial biomass N at reproductive growth stage, while M4 and CK had it at vegetative growth stage. The significant difference of soil microbial biomass N caused by different treatments was not changed with plant growth stages. The dynamics of soil microbial biomass N had a significant correlation some soil biological, physical and chemical properties. A significant positive correlation was found between soil microbial biomass N and soil biological, physical and chemical properties, plant N, P and K contents, soil moisture, and grain crude protein.

China↗

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↗

PubMed1999

A simple structured model for maintenance, biomass formation, and ajmalicine production by nondividing Catharanthus roseus cells.

The stoichiometry of maintenance and carbohydrate storage as well as ajmalicine production kinetics of non-dividing Catharanthus roseus cells in the second stage of a two-stage batch process were investigated. For the mathematical description of these processes, a simple structured model with 5 parameters is proposed. In the model the biomass is divided in two compartments: active biomass and storage carbohydrates. In induction medium (standard medium without phosphate, nitrogen and hormones), biomass formation, glucose consumption, and CO(2) production appeared to be constant in time. Therefore, it is assumed that the active biomass level is constant. The maintenance coefficient m(S), and the yield of storage carbohydrates on glucose Y(SC) were optimized by fitting the model on experimental data: 0.003 C-mol/C-mol/h and 0.82 C-mol/C-mol, respectively. Production kinetics were incorporated in this model and related to the active biomass fraction. The maximum specific ajmalicine production rate q(p)(max) was fitted on the data: 7.5 micromol/C-mol/h. The model was tested at several different experimental conditions, and proved to describe the experimental results adequately. An independent experiment at a very high cell density in order to obtain maximum product formation was used to validate the model. It provided a satisfactory description of the results, but the final ajmalicine concentration (198 micromol/L after 18 days) was lower than the calculated maximum, due to accumulation of inhibiting gaseous metabolites.

Biomass↗

PubMed1997

The primate community of the Lopé Reserve, Gabon: diets, responses to fruit scarcity, and effects on biomass.

The diets of all diurnal primates (Gorilla g. gorilla, Pan t. troglodytes, Mandrillus sphinx, Colobus satanas, Cercocebus albigena, Cercopithecus nictitans, C. pogonias, C. cephus) in the Lópe Reserve, central Gabon, are described from qualitative and quantitative data collected over 10 years. A total of 397 foods were recorded, of which 91% were from plants. The diet of seven of the eight species were numerically dominated by fruit, the exception being Colobus satanas with a diet dominated by seeds. When proportion of feeding time was examined, fruit remained the dominant food class for six species, while Cercocebus albigena, like the black colobus, spent most time feeding on seeds. The number of foods recorded per species ranged from 46-220, but dietary breadth of the four species that have not been subjects of detailed study was certainly underestimated. Almost half of the foods (46%) were eaten by only one species, and only four (1%) were recorded for all eight species. At Lópe, fruit is scarce for 2-3 months during the annual dry season, and fruit crop failures can prolong this period of scarcity to as many as 8 months in some years. When fruit is scarce, the diets of all the species changed to include more nonfruit foods, but chimpanzees and the three species of guenons maintained a fruit dominated diet. The total biomass of the Lópe primate community is 374 kg/km2, which is low compared to other sites in tropical Africa. Within the Lópe community, biomass correlates negativity with degree of frugivory, suggesting that fruit availability may be critical, but this does not explain the low total biomass compared to other sites. Neither floristic diversity nor the composition of the primate community at Lópe can account for the biomass. While historical events such as climate-induced changes in forrest cover, disease, or impact of human activities cannot be ruled out, we conclude that the most likely explanation of low primate biomass is the occurrence of an ecological "catastrophe" in the fairly recent past from which populations have not yet recovered. We believe that the most likely scenario was climate-mediated disturbance of flowering of important fruit food species. Prolonged fruit scarcity would have caused mortalities and affected the most frugivorous species more severely.

Animals↗

PubMed2002

Determination of biomass detachment rate coefficients in anaerobic fluidized-bed-GAC reactors.

In this study a simple analytical technique that determines the active biomass in a sample capable of degrading specific substrates anaerobically was developed and used to measure first-order detachment rate coefficients of acetate and phenol utilizing organisms. Different detachment rate coefficients were measured for the two microbial populations. A general relationship between the detachment rate coefficients and biomass accumulation was developed. The detachment rate coefficient was found to increase sharply after a certain biomass accumulation until it reaches a maximum, after which it decreases continuously with increasing biomass until it levels off at a constant value independent of biomass. Detachment rate coefficients measured in different reactors, operating at different conditions with respect to loading, biological SRT, and attachment media particle size, were in close agreement with each other after being normalized to the shear stress and daily methane production rate per unit biofilm area.

Acetates↗

PubMed2003

Influence of morphology on the near-infrared spectra of mycelial biomass and its implications in bioprocess monitoring.

Bioprocesses that employ mycelial microorganisms are commercially important. The application of optical techniques for the measurement of biomass in such processes is limited by the morphological heterogeneity exhibited by the mycelial microorganism employed. We investigated the influence of morphology on the near-infrared (NIR) spectra of the biomass of Streptomyces fradiae, a filamentous microorganism, by studying the spectra of mycelial suspensions that were manipulated to generate a range of morphological forms. Computerized image analysis was used to characterize the morphological forms. Principal component analysis was used to assess the spectral variations and study correlations to the manipulated mycelial morphology. Although morphology was found to influence the near infrared transmittance spectra of biomass, the influence was less pronounced than in the visible region, the spectral information at longer wavelengths (1600-2350 nm) showing greater stability to morphological variations. Long-wave NIR spectral information is therefore likely to be more useful in estimating biomass in mycelial bioprocesses. Furthermore, the NIR reflectance spectra of dried biomass were found to show correlations to the morphological variations introduced, suggesting that NIR spectra may be useful in obtaining morphology related information.

Bacterial Proteins↗

PubMed2004

Production of nickel bio-ore from hyperaccumulator plant biomass: applications in phytomining.

An important step in phytomining operations is the recovery of metal from harvested plant material. In this work, a laboratory-scale horizontal tube furnace was used to generate Ni-enriched bio-ore from the dried biomass of Ni hyperaccumulator plants. Prior to furnace treatment, hairy roots of Alyssum bertolonii were exposed to Ni in liquid medium to give biomass Ni concentrations of 1.9% to 7.7% dry weight; whole plants of Berkheya coddii were grown in Ni-containing soil to produce above-ground Ni levels of up to 0.49% dry weight. The concentration of Ca in the Ni-treated B. coddii biomass was about 15 times greater than in A. bertolonii. After furnace treatment at 1200 degrees C under air, Ni-bearing residues with crystalline morphology and containing up to 82% Ni were generated from A. bertolonii. The net weight loss in the furnace and the degree of concentration of Ni were significantly reduced when the furnace was purged with nitrogen, reflecting the importance of oxidative processes in Ni enrichment. Ni in the B. coddii biomass was concentrated by a factor of about 17 to yield a residue containing 8.6% Ni; this bio-ore Ni content is substantially higher than the 1% to 2% Ni typically found in mined ore. However, the B. coddii samples after furnace treatment also contained about 34% Ca, mainly in the form of hydroxyapatite Ca(5)(PO(4))(3)OH. Such high Ca levels may present significant challenges for further metallurgical processing. This work demonstrates the feasibility of furnace treatment for generating Ni-rich bio-ore from hyperaccumulator plants. The results also suggest that minimizing the uptake of Ca and/or reducing the Ca content of the biomass prior to furnace treatment would be a worthwhile strategy for improving the quality of Ni bio-ore produced in phytomining operations.

Asteraceae↗

PubMed2006

Adsorptive removal of textile dyes from aqueous solutions by dead fungal biomass.

Dead fungal biomass prepared from Phanerochaete chrysosporium and Funalia trogii was tested for their efficiency in removal of textile dyes. The effects of contact time, initial dye concentration, amount of dead biomass and agitation rate on dye removal have been determined. Removal of all dyes required a very short time (60 min). Experimental results show that, P. chrysosporium was more effective than F. trogii . An increase in the amount of dead biomass positively affected of the dye removal. The removal efficiency of different amount of biomass was in order 1 g > 0.5 g > 0.2 g > 0.1 g. The highest removal was obtained at 150-200 rpm. Slightly lower removing activities were found at lower agitation rates. This study showed that it was possible to remove textile dyes by dead biomass of P. chrysosporium .

Biodegradation, Environmental↗

PubMed2000

Use of bioluminometry for determination of active yeast biomass immobilized in ionotropic hydrogels.

The technique of bioluminometry was used to determine the biomass concentration of yeast cells immobilized in ionotropic hydrogel beads, including alginate, pectate, and kappa-carrageenan. The method uses determination of ATP extracted from viable cells, the concentration of which is then expressed as the active biomass concentration. Seven yeast strains divided into three categories (brewing, wine-making, and ethanol-producing yeasts) were tested, and different biomass concentrations were determined in all three immobilization materials. The described method is characterized by a good correlation (up to 99%) to classical dry biomass determination. The method is quicker, easier, and not so laborious, providing sufficient determination accuracy, and can be used for a rapid estimation of viable biomass in most biotechnological processes using immobilized living cells.

Biomass↗

PubMed2005

Characterisation of selenium compounds in rye seedling biomass using 75Se-labelling/SDS-PAGE separation/gamma-scintillation counting, and HPLC-ICP-MS analysis of a range of enzymatic digests.

In the present study, selenium-enriched plant biomass was investigated to evaluate the ability of rye seedlings to take up, and assimilate, inorganic selenium. Two different analytical approaches were used. Electrophoretic separation (SDS-PAGE) of proteins extracted from 75Se-labelled biomass was used to investigate the biotransformation of selenite into organic forms of the element. Ion-pair chromatography coupled with ICP-MS detection was chosen for the analysis of selenium species, enzymatically extracted from the plant biomass. The results of three enzymatic hydrolysis procedures and three sequential enzymatic extractions procedures are compared. The most effective single extraction was proteolysis (using protease type XIV), giving an overall extraction efficiency of 48%. However, for combinations of enzymes, the most effective was cellulase (Trichoderma viride) followed by sequential extraction of the solid pellet using protease type XIV, giving an extraction efficiency of 70%. The complementary data from the electrophoretic fractionation of proteins, and the HPLC separation of Se-species in the proteolytic digests, reveal the existence of large number of selenium-containing compounds in the rye seedling plant biomass. The results showed the complete biotransformation of inorganic selenium into organic forms during germination of the rye seedlings. HPLC-ICP-MS analysis of extracts from the plant biomass did not show the presence of selenate or selenite. At the time of this study, the lack of suitable organic-MS facilities meant that it was not possible to characterise them fully. However, the data does show that a combination of different enzymes, rather than just the commonly-used protease, should be considered when developing an extraction strategy for selenium in different food types to those already reported in the literature.

Biomass↗

PubMed2003

Dietary shift and lowered biomass gain of a generalist herbivore in species-poor experimental plant communities.

Species loss of primary producers is likely to affect processes on other trophic levels. We studied consumption and individual performance of the generalist herbivore Parapleurus alliaceus (Orthoptera) in relation to the species richness of primary producers. Adult grasshoppers were caged and left to feed for 2 weeks on experimental grassland communities ranging in plant species richness from one, two, four, eight to 32 species. Low plant diversity had a negative effect on both plant community biomass and on biomass gain of female grasshoppers, feeding to produce eggs (male grasshoppers did not gain biomass during the feeding period). This was surprising because plots with high plant diversity had a low proportion of grass biomass and grasshoppers preferentially selected grasses, leading to a greater exploitation of grasses in experimental communities of higher diversity. Thus, the concurrent increase in non-grass species in the diet from these high-diversity communities must have been beneficial to the generalist herbivore. In addition to the positive effects of plant diversity, the presence of legumes in a mixture with grasses further enhanced the biomass gain of grasshoppers at a given level of diversity. These findings suggest that plant species loss may lead to shifts in herbivore population sizes, reducing those of generalists and benefiting specialists of the remaining plant species. Our results further suggest that generalist herbivores, by having feeding preferences, can also change the relative abundances of plant species with different functional characteristics. This may feedback on both composition and diversity of plant communities.

Animals↗

PubMed2006

Biomass responses to elevated CO2, soil heterogeneity and diversity: an experimental assessment with grassland assemblages.

While it is well-established that the spatial distribution of soil nutrients (soil heterogeneity) influences the competitive ability and survival of individual plants, as well as the productivity of plant communities, there is a paucity of data on how soil heterogeneity and global change drivers interact to affect plant performance and ecosystem functioning. To evaluate the effects of elevated CO(2), soil heterogeneity and diversity (species richness and composition) on productivity, patterns of biomass allocation and root foraging precision, we conducted an experiment with grassland assemblages formed by monocultures, two- and three-species mixtures of Lolium perenne, Plantago lanceolata and Holcus lanatus. The experiment lasted for 90 days, and was conducted on microcosms built out of PVC pipe (length 38 cm, internal diameter 10 cm). When nutrients were heterogeneously supplied (in discrete patches), assemblages exhibited precise root foraging patterns, and had higher total, above- and belowground biomass. Greater aboveground biomass was observed under elevated CO(2). Species composition affected the below:aboveground biomass ratio and interacted with nutrient heterogeneity to determine belowground and total biomass. Species richness had no significant effects, and did not interact with either CO(2) or nutrient heterogeneity. Under elevated CO(2) conditions, the two- and three-species mixtures showed a clear trend towards underyielding. Our results show that differences among composition levels were dependent on soil heterogeneity, highlighting its potential role in modulating diversity-productivity relationships.

Analysis of Variance↗

PubMed2005

Production of lactic acid and fungal biomass by Rhizopus fungi from food processing waste streams.

This study proposed a novel waste utilization bioprocess for production of lactic acid and fungal biomass from waste streams by fungal species of Rhizopus arrhizus 36017 and R. oryzae 2062. The lactic acid and fungal biomass were produced in a single-stage simultaneous saccharification and fermentation process using potato, corn, wheat and pineapple waste streams as production media. R. arrhizus 36017 gave a high lactic acid yield up to 0.94-0.97 g/g of starch or sugars associated with 4-5 g/l of fungal biomass produced, while 17-19 g/l fungal biomass with a lactic acid yield of 0.65-0.76 g/g was produced by the R. oryzae 2062 in 36-48 h fermentation. Supplementation of 2 g/l of ammonium sulfate, yeast extract and peptone stimulated an increase in 8-15% lactic acid yield and 10-20% fungal biomass.

Ananas↗