Cascade utilization of water chestnut: recovery of phenolics, phosphorus, and sugars

Overgrowth of aquatic plants, such as water chestnut, has been reported as a regional problem in various areas. We proposed cascade utilization of water chestnut through the recovery of phenolics, phosphorus, and sugars. Phenolics were extracted using 50 g (wet weight) of biomass with 300 mL of acetone, methanol, or hot water, and the yields of total phenolics were 80.2, 56.2, and 49.7 mg?g^?1 dry weight of native biomass, respectively. The rate of eluted phosphorus in the phenolic extraction step was 8.6, 14.8, and 45.3 % of that in the native biomass, respectively, indicating that the use of polar organic solvents suppressed phosphorus elution at the phenolic extraction step. Extraction of phosphorus following the phenolic extraction was combined with alkaline pretreatment (1 % NaOH solution) of biomass for saccharification; 64.1 and 51.0 % of phosphorus in the native biomass were extracted using acetone and methanol for the phenolic extraction, respectively. Saccharification following the alkaline pretreatment showed that the glucose recovery rates were significantly increased (p?<?0.05) with the phenolic extraction step compared to alkaline pretreatment alone. This finding indicates that extraction of phenolics not only provides another useful material but also facilitates enzymatic saccharification.     

A Predictive Mechanism for Mercury Oxidation on Selective Catalytic Reduction Catalysts under Coal-Derived Flue Gas

Abstract

This paper introduces a predictive mechanism for elemental mercury (Hg⁰) oxidation on selective catalytic reduction (SCR) catalysts in coal-fired utility gas cleaning systems, given the ammonia (NH₃)/nitric oxide (NO) ratio and concentrations of Hg⁰ and HCl at the monolith inlet, the monolith pitch and channel shape, and the SCR temperature and space velocity. A simple premise connects the established mechanism for catalytic NO reduction to the Hg⁰ oxidation behavior on SCRs: that hydrochloric acid (HCl) competes for surface sites with NH₃ and that Hg⁰ contacts these chlorinated sites either from the gas phase or as a weakly adsorbed species. This mechanism explicitly accounts for the inhibition of Hg⁰ oxidation by NH₃, so that the monolith sustains two chemically distinct regions. In the inlet region, strong NH₃ adsorption minimizes the coverage of chlorinated surface sites, so NO reduction inhibits Hg⁰ oxidation. But once NH₃ has been consumed, the Hg⁰ oxidation rate rapidly accelerates, even while the HCl concentration in the gas phase is uniform. Factors that shorten the length of the NO reduction region, such as smaller channel pitches and converting from square to circular channels, and factors that enhance surface chlorination, such as higher inlet HCl concentrations and lower NH₃/NO ratios, promote Hg⁰ oxidation.

This mechanism accurately interprets the reported tendencies for greater extents of Hg⁰ oxidation on honeycomb monoliths with smaller channel pitches and hotter temperatures and the tendency for lower extents of Hg⁰ oxidation for hotter temperatures on plate monoliths. The mechanism also depicts the inhibition of Hg⁰ oxidation by NH₃ for NH₃/NO ratios from zero to 0.9. Perhaps most important for practical applications, the mechanism reproduces the reported extents of Hg⁰ oxidation on a single catalyst for four coals that generated HCl concentrations from 8 to 241 ppm, which covers the entire range encountered in the U.S. utility industry. Similar performance is also demonstrated for full-scale SCRs with diverse coal types and operating conditions.     

Identification of microbial populations contributing to nitrification-associated nitrous oxide emission during cattle manure composting process with forced aeration

Journal of Material Cycles and Waste Management - This study was conducted to clarify the fates of whole nitrogen cycle-associated microorganisms during laboratory-scale composting of cattle manure...     

Utilization of water chestnut for reclamation of water environment and control of cyanobacterial blooms

Overgrowth of water chestnut (Trapa spp.) is a regional problem throughout Asia and North America because of waterway blockage and water fouling upon decomposition. In the present study, we investigated the potential of water chestnut to control cyanobacterial blooms, via a high content of phenolic compounds. In addition, we assessed the impact of biomass harvesting and crude extract application on nutrient balance. We showed that the floating parts of water chestnut contained high concentrations of total phenolics (89.2 mg g^?1 dry weight) and exhibited strong antioxidant activity (1.31 mmol g^?1 dry weight). Methanol-extracted phenolics inhibited growth of Microcystis aeruginosa; the half maximal effective concentration (EC₅₀) of the extracted phenolics was 5.8 mg L^?1, which was obtained from only 103 mg L^?1 of dry biomass (the floating and submerged parts). However, the crude extracts also added important quantities of nitrogen, phosphorus, and potassium (1.49, 1.05, and 16.3 mg g^?1, respectively; extracted dry biomass weight basis); therefore, in practice, nutrient removal before and/or after the extraction is essential. On the other hand, biomass harvesting enables recovery of nitrogen, phosphorus, and potassium from the water environment (23.1, 2.9, and 18.7 mg g^?1, respectively; dry biomass weight basis). Our findings indicate that water chestnut contains high concentrations of phenolics and exhibits strong antioxidant activity. Utilization of these resources, including nutrients, will contribute to reclamation of the water environment, and also to disposal of wet biomass.     

Demographic heterogeneity, cohort selection, and population growth

Demographic heterogeneity--variation among individuals in survival and reproduction--is ubiquitous in natural populations. Structured population models address heterogeneity due to age, size, or major developmental stages. However, other important sources of demographic heterogeneity, such as genetic variation, spatial heterogeneity in the environment, maternal effects, and differential exposure to stressors, are often not easily measured and hence are modeled as stochasticity. Recent research has elucidated the role of demographic heterogeneity in changing the magnitude of demographic stochasticity in small populations. Here we demonstrate a previously unrecognized effect: heterogeneous survival in long-lived species can increase the long-term growth rate in populations of any size. We illustrate this result using simple models in which each individual's annual survival rate is independent of age but survival may differ among individuals within a cohort. Similar models, but with nonoverlapping generations, have been extensively studied by demographers, who showed that, because the more "frail" individuals are more likely to die at a young age, the average survival rate of the cohort increases with age. Within ecology and evolution, this phenomenon of "cohort selection" is increasingly appreciated as a confounding factor in studies of senescence. We show that, when placed in a population model with overlapping generations, this heterogeneity also causes the asymptotic population growth rate lambda to increase, relative to a homogeneous population with the same mean survival rate at birth. The increase occurs because, even integrating over all the cohorts in the population, the population becomes increasingly dominated by the more robust individuals. The growth rate increases monotonically with the variance in survival rates, and the effect can be substantial, easily doubling the growth rate of slow-growing populations. Correlations between parent and offspring phenotype change the magnitude of the increase in lambda, but the increase occurs even for negative parent-offspring correlations. The effect of heterogeneity in reproductive rate on lambda is quite different: growth rate increases with reproductive heterogeneity for positive parent-offspring correlation but decreases for negative parent-offspring correlation. These effects of demographic heterogeneity on lambda have important implications for population dynamics, population viability analysis, and evolution.     

Cycling of rare earth elements in the atmosphere in central Tokyo

Concentrations of 14 rare earth elements (REEs) in six size classes of airborne particulate matter (APM) (<0.43, 0.43-0.65, 0.65-1.1, 1.1-2.1, 2.1-11, and >11 μm) and in two different phases (suspended particulate and dissolved) in rainwater were determined by inductively coupled plasma mass spectrometry (ICP-MS). Positive Eu and Tb anomalies were observed in size-classified APM. These anomalies may be due to large emissions of Eu and Tb to the atmosphere resulting from the recent change in Japan from the use of cathode-ray tubes to plasma displays in television sets (Eu and Tb) and from the widespread use of magneto-optical disks (Tb). The light REEs were enriched in fine APM particles (diameter < 1.1 μm). Because compositions of La/Ce/Sm in fine APM (diameter < 1.1 μm) were similar to those in automobile catalyst, the light REE enrichment was attributed to automobile emissions. In contrast, the REE distribution pattern in the suspended particulate phase in rainwater was similar to that in coarse APM (diameter > 2.1 μm), and a positive Tb anomaly was observed, suggesting that coarse particles easily become trapped in rain droplets. A negative Eu anomaly was observed in the dissolved phase in rainwater, but not in APM or in the suspended particulate phase in rainwater. Unlike other REEs, Eu can exist as both bivalent and trivalent ions in nature, and Eu-selective dissolution from or adsorption onto the trapped particles of Eu might account for the negative anomaly. These results show that atmospheric REE cycling is affected by the physico-chemical properties of APM.     

Postembryonic development of the bone-eating worm Osedax japonicus

Bone-eating worms of the genus Osedax exclusively inhabit sunken vertebrate bones on the seafloor. The unique lifestyle and morphology of Osedax spp. have received much scientific attention, but the whole process of their development has not been observed. We herein report the postembryonic development and settlement of Osedax japonicus Fujikura et al. (Zool Sci 23:733–740, 2006). Fertilised eggs were spawned into the mucus of a female, and the larvae swam out from the mucus at the trochophore stage. Larvae survived for 10 days under laboratory conditions. The larvae settled on bones, elongated their bodies and crawled around on the bones. Then they secreted mucus to create a tube and the palps started to develop. The palps of O. japonicus arose from the prostomium, whereas the anterior appendages of other siboglinids arose from the peristomium. The recruitment of dwarf males was induced by rearing larvae with adult females. Females started to spawn eggs 6 weeks after settlement.     

Formation of PCDDs and PCDFs during the combustion of polyvinylidene chloride and other polymers in the presence of HCl

PVDC and three non-chlorinated polymers (PP, PET, and PA) were incinerated at 700-850 degrees C in a laboratory-scale quartz tubular furnace in the presence of HCl (ca. 500 ppm congruent with 0.8 mg/l), and the gas-phase formation of PCDD/Fs, their putative precursors and their homologue profiles were investigated. The addition of HCl had little or no apparent effect on the level of PCDD/Fs formation during PVDC combustion, and their homologue profiles were quite different from those of the three non-chlorinated polymers. With PVDC, O8CDD and particularly O8CDF were by far most prevalent, apparently as a result of the selective formation of the precursors. With each of the three non-chlorinated polymers, combustion at 800 degrees C or higher in the presence of HCl resulted in PCDD/Fs formation at levels equaling or exceeding those observed with PVDC. In trials made with one of them (PP) under the same conditions but using a large polymer sample (100 mg vs 20 mg in all other trials), the level of PCDD/Fs formation was far higher than with the smaller polymer samples, and thus demonstrated the importance of appropriate combustion conditions for polymer incineration.     

DNA-based prenatal carrier detection for group a xeroderma pigmentosum in a chorionic villus sample

DNA-based prenatal carrier detection of group A xeroderma pigmentosum (XP-A) is reported. Chorionic villus sampling was done at the tenth gestational week in a pregnant woman whose first child suffers from XP-A. Genomic DNAs from the villi, proband, and parents were PCR (polymerase chain reaction)-amplified using three sets of primers, because the PCR and a subsequent enzyme digestion with HphI, AlwNI, or MseI may detect the three most frequent mutations of the XP-A complementing gene (XPAC) in Japanese XP-A patients. The results showed that the proband is a homozygote and that the parents and fetus are heterozygotes for a base substitution at the 3′ acceptor site of intron 3 of XPAC, indicating that the fetus is a healthy carrier of XP-A. This is the first case of prenatal carrier detection of the disorder.