Non‐specific phospholipase C1 affects silicon distribution and mechanical strength in stem nodes of rice

Silicon, the second abundant element in the crust, is beneficial for plant growth, mechanical strength, and stress responses. Here we show that manipulation of the non‐specific phospholipase C1, NPC1, alters silicon content in nodes and husks of rice (Oryza sativa). Silicon content in NPC1‐overexpressing (OE) plants was decreased in nodes but increased in husks compared to wild‐type, whereas RNAi suppression of NPC1 resulted in the opposite changes to those of NPC1‐OE plants. NPC1 from rice hydrolyzed phospholipids and galactolipids to generate diacylglycerol that can be phosphorylated to phosphatidic acid. Phosphatidic acid interacts with Lsi6, a silicon transporter that is expressed at the highest level in nodes. In addition, the node cells of NPC1‐OE plants have lower contents of cellulose and hemicellulose, and thinner sclerenchyma and vascular bundle fibre cells than wild‐type plants; whereas NPC1‐RNAi plants displayed the opposite changes. These data indicate that NPC1 modulates silicon distribution and secondary cell wall deposition in nodes and grains, affecting mechanical strength and seed shattering.     

Organic acids associated with saccharification of cellulosic wastes during solid-state fermentation

Saccharification of five cellulosic wastes, i.e. rice husks, wheat bran, corn cobs, wheat straw and rice straw by three cellulytic fungi, i.e. Aspergillus glaums MN1, Aspergillus oryzae MN2 and Penicillium purpurogenum MN3, during solid-state fermentation (SSF) was laboratory studied. Rice husks, wheat bran, and corn cobs were selected as inducers of glucose production in the tested fungi. An incubation interval of 10 days was optimal for glucose production. Maximal activities of the cellulases FP-ase, CMC-ase, and p-glucosidase were detected during SSF of rice husks by P. purpurogenum; however, a-amylase activity (7.2 U/g) was comparatively reduced. Meanwhile, the productivities of FP-ase, CMC-ase, and β-glucosidase were high during SSF of rice husks by A glaucus; however, they decreased during SSF of corn cobs by P. purpurogenum. Addition of rock phosphate (RP) (75 mg P₂O₅) decreased the pH of SSF media. (NH₄)₂SO₄ was found to be less inducer of cellulytic enzymes, during SSF of rice husks by A. glaucus or A. oryzae; it also induced phytase production and solubilization of RP. The organic acids associated with saccharification of the wastes studied have also been investigated. The highest concentration of levulinic acid was detected (46.15 mg/g) during SSF of corn cobs by P. purpurogenum. Likewise, oxalic acid concentration was 43.20 mg/g during SSF of rice husks by P. purpurogenum.     

不同施肥水平对不同品种小麦籽粒蛋白质和地上器官游离氨基酸含量的影响

研究了小麦不同品种开花后各地上器官游离氨基酸含量的变化动态及其与籽粒蛋白质含量的关系,以及氮素营养的调节作用。结果表明,小麦叶片和颖壳十穗轴游离氨基酸含量均在开花后持续增加,至花后14d达到最大值,之后开始下降。茎和叶鞘游离氨基酸含量则在开花后上升较缓慢,至花后21d达最大值。籽粒游离氨基酸含量一般在开花后就持续降低。各地上器官游离氨基酸含量与成熟期籽粒蛋白质含量均呈显著或极显著正相关,说明源器宫中游离氨基酸供应充足,有利于籽粒蛋白质积累。增施氮肥能够提高各地上器官中的游离氨基酸含量,进而促进籽粒蛋白质的合成,提高籽粒蛋白质含量。品种之间籽粒蛋白质含量的差异,是由各地上营养器官向籽粒运输氨基酸的综合作用所造成的。     

Effect of anatomical fractionation on the enzymatic hydrolysis of acid and alkaline pretreated corn stover

Due to concerns with biomass collection systems and soil sustainability there are opportunities to investigate the optimal plant fractions to collect for conversion. An ideal feedstock would require a low severity pretreatment to release a maximum amount of sugar during enzymatic hydrolysis. Corn stover fractions were separated manually and analyzed for glucan, xylan, acid soluble lignin, acid insoluble lignin, and ash composition. The stover fractions were also pretreated with either 0%, 0.4%, or 0.8% NaOH for 2 h at room temperature, washed, autoclaved and saccharified. In addition, dilute sulfuric acid pretreated samples underwent simultaneous saccharification and fermentation (SSF) to ethanol. In general, the two pretreatments produced similar trends with cobs, husks, and leaves responding best to the pretreatments, the tops of stalks responding slightly less, and the bottom of the stalks responding the least. For example, corn husks pretreated with 0.8% NaOH released over 90% (standard error of 3.8%) of the available glucan, while only 45% (standard error of 1.1%) of the glucan was produced from identically treated stalk bottoms. Estimates of the theoretical ethanol yield using acid pretreatment followed by SSF were 65% (standard error of 15.9%) for husks and 29% (standard error of 1.8%) for stalk bottoms. This suggests that integration of biomass collection systems to remove sustainable feedstocks could be integrated with the processes within a biorefinery to minimize overall ethanol production costs.     

Blueberry husks and probiotics attenuate colorectal inflammation and oncogenesis, and liver injuries in rats exposed to cycling DSS-treatment

Long-term colonic inflammation promotes carcinogenesis and histological abnormalities of the liver, and colorectal tumours frequently arise in a background of dysplasia, a precursor of adenomas. Altered colonic microbiota with an increased proportion of bacteria with pro-inflammatory characteristics, have been implicated in neoplastic progression. The composition of the microbiota can be modified by dietary components such as probiotics, polyphenols and dietary fibres. In the present study, the influence of probiotics in combination with blueberry husks on colorectal carcinogenesis and subsequent liver damage was evaluated.Colorectal tumours were induced in rats by cyclic treatment with dextran sulphate sodium (DSS). Blueberry husks and a mixture of three probiotic strains (Bifidobacterium infantis DSM 15159, Lactobacillus gasseri, DSM 16737 and Lactobacillus plantarum DSM 15313) supplemented a basic diet fortified with oats. The condition of the rats was monitored using a disease activity index (DAI). A qualitative and quantitative histological judgement was performed on segments of distal colon and rectum and the caudate lobe of the liver. The formation of short-chain fatty acids, bacterial translocation, the inflammatory reaction and viable count of lactobacilli and Enterobaceriaceae were addressed.Blueberry husks with or without probiotics significantly decreased DAI, and significantly reduced the number of colonic ulcers and dysplastic lesions. With a decreased proportion of blueberry husk in the diet, the probiotic supplement was needed to achieve a significant decrease in numbers of dysplastic lesions. Probiotics decreased faecal viable count of Enterobacteriaceae and increased that of lactobacilli. Blueberry husks with or without probiotics lowered the proportion of butyric acid in distal colon, and decreased the haptoglobin levels. Probiotics mitigated hepatic injuries by decreasing parenchymal infiltration and the incidence of stasis and translocation. The results demonstrate a dietary option for use of blueberry husks and probiotics to delay colonic carcinogenesis and hepatic injuries in the rat model.     

Stimulation of mycelia growth in several mushroom species by rice husks

When supplemented to the culture medium of mushroom Coprinus cinereus, rice husks soaked beforehand in methanol stimulated mycelia growth up to a concentration of 80 mg/ml dose-dependently, whereas the non-treated stimulated mycelia growth up to 20 mg/ml. This result suggests the existence of both stimulatory and inhibitory substances in rice husks. Since momilactone A (MLA) is recognized as one of the phytoalexins in rice husks, its biological activity against mycelia growth was tested. Momilactone A inhibited mycelia growth at 5 microg/disc, whereas the methanol extract of husks did so at 1 mg/disc, wherein 0.2 microg of MLA was estimated by LC/MS/MS. Thus the phytoalexins including MLA should inhibit mycelia growth. Rice husks stimulated mycelia growth in some edible mushroom species such as Grifola frondosa (maitake), Lentinus edodes (shiitake), Pleurotus eryngii (eringi), and P. ostreatus (hiratake). Our findings might lead to the development of new profitable cultivation methods for mushrooms using rice husks.     

Evidence of the presence of 2-O-beta-D-xylopyranosyl-alpha-l-arabinofuranose side chains in barley husk arabinoxylan

(Glucurono)arabinoxylans were extracted from barley husks and degraded with endo-beta-xylanase or subjected to periodate oxidation. The released oligosaccharide fragments were separated and isolated on Biogel-P2, and their structures were determined by NMR spectroscopy. The oligosaccharides identified consisted of beta-d-(1-->4)-linked xylopyranosyl residues, of which some were substituted at O-3 with alpha-l-arabinofuranosyl groups or at O-2 with 4-O-methylglucuronic acid. In addition to these substituents, a disaccharide side chain, 2-O-beta-d-xylopyranosyl-alpha-l-arabinofuranose, attached at position O-3 of the main chain, was proved to exist in arabinoxylan from barley husks. The compound was fully characterized with NMR, and all (1)H and (13)C NMR signals were assigned. The arabinose to xylose ratio was low (approximately 0.2) and no 2,3-disubstitution existed. No blocks of substituted xylose residues could be observed along the main chain.     

Feasibility of ethanol production from coffee husks

The objective of this work was to evaluate the feasibility of ethanol production by fermentation of coffee husks by Saccharomyces cerevisiae. Batch fermentation studies were performed employing whole and ground coffee husks, and aqueous extract from ground coffee husks. It was observed that fermentation yield decreased with an increase in yeast concentration. The best results were obtained for the following conditions: whole coffee husks, 3 g yeast/l substrate, temperature of 30°C. Under these conditions ethanol production was 8.49 ± 0.29 g/100 g dry basis (13.6 ± 0.5 g ethanol/l), a satisfactory value in comparison to literature data for other residues such as corn stalks, barley straw and hydrolyzed wheat stillage (5–11 g ethanol/l). Such results indicate that coffee husks present excellent potential for residue-based ethanol production.     

Adsorption of paraquat using methacrylic acid-modified rice husk

This work investigates the adsorption of paraquat from aqueous medium using a methacrylic acid (MAA)-modified rice husk. The carboxyl groups were chemically bound to the surface of the rice husk by graft copolymerization using Fenton's reagent as a redox initiator. The graft copolymerization was examined to determine the H(2)O(2) concentration and the amount of MAA monomer used. FT-IR spectra confirmed the presence of carbonyl groups on the structural units of the rice husk derivative. The MAA-modified rice husks were hydrolyzed to sodium salt and used to adsorb paraquat. The adsorption was rapid in the first few minutes and quickly reached equilibrium. Equilibrium adsorption data are more consistent with the Langmuir isotherm equation than with the Freundlich equation. The maximum adsorption capacity of modified rice husks was 317.7mg/g-adsorbent. This value clearly exceeds the 60mg/g of Fuller's earth and the 90mg/g of activated carbon, which are the most commonly used binding agents for paraquat.     

Adsorption characteristics of malachite green on activated carbon derived from rice husks produced by chemical-thermal process

Phosphoric acid (H(3)PO(4)) and sodium hydroxide (NaOH) treated rice husks, followed by carbonization in a flowing nitrogen were used to study the adsorption of malachite green (MG) in aqueous solution. The effect of adsorption on contact time, concentration of MG and adsorbent dosage of the samples treated or carbonized at different temperatures were investigated. The results reveal that the optimum carbonization temperature is 500 degrees C in order to obtain adsorption capacity that is comparable to the commercial activated carbon for the husks treated by H(3)PO(4). It is interesting to note that MG adsorbed preferably on carbon-rich than on silica rich-sites. It is found that the behaviour of H(3)PO(4) treated absorbent followed both the Langmuir and Freundlich models while NaOH treated best fitted to only the Langmuir model.     

Enzymatic hydrolysis of cellulose from oat husks at different substrate concentrations

Pulps prepared from oat husks via a method combining prehydrolysis, alkali delignification, and nitric acid treatment were demonstrated to possess high fermentability upon hydrolysis using multienzyme preparations, such as BrewZyme BGX and CelloLux-A. A dependence of the increment of the yield of reducing substances on the initial substrate concentration ranging from 15 to 120 g/dm³ was studied. The final yield of reducers at 72 h was shown to decline from 88 to 65% with an increase in the initial concentration of the substrate.     

Steam-explosion of olive stones: hemicellulose solubilization and enhancement of enzymatic hydrolysis of cellulose

Olive stones (whole stones and seed husks in fragments) were processed by steam-explosion under different experimental conditions of temperature and time, 200-236 degrees C for 2-4 min, with or without previous acid impregnation with 0.1%, H2SO4 (w/w). This paper examines the solubilization of hemicelluloses and their molecular weight distribution. The subsequent enzymatic hydrolysis of the solid residue, using a preparation of cellulase, was also studied. The maximum yield of the pentosan recovered in the water solution was 63% pentose in the starting material for seed husk treated at 200 degrees C for 2 min (log R0 3.24) prior to acid-impregnation, or at 215 degrees C for 2 min (log R0 3.69) without acid, compared to 39% of the potential yield for whole stones pre-impregnated with acid under more severe conditions (at log R0 = 4.07). This indicates that the autohydrolysis of hemicellulose in seed husks when compared to whole stones is enhanced. The molecular weight distribution of profile sugars showed that the depolymerization of hemicelluloses is a function of the severity of the treatment. Steam-explosion improved the accessibility of the cellulose and increased the enzymatic hydrolysis yield after steam-explosion with respect to material without steam explosion (ball-milled material), although little increase in the extent of saccharification occurred when the alkali-soluble lignin was removed. Only when the substrate was post-treated with Na-chlorite was the enzymatic hydrolysis improved, the water-insoluble residue being almost completely hydrolyzed in 8 h of incubation.     

Anaerobic digestion of spent bedding from deep litter piggery housing

This paper investigates spent litter from deep litter piggery housing as a potential substrate for farm-scale anaerobic digestion. Degradability and degradation rates were evaluated under mesophilic conditions for unused, lightly soiled (used by weaner/small pigs), and heavily soiled (used by finishing/large pigs) wheat straw, barley straw, and rice husks bedding. Apparent first order hydrolysis rate coefficients varied, but were comparable across all samples analysed (<0.1 day^?1). Spent wheat straw was generally more degradable (approximately 60%) than spent barley straw, while spent barley straw was comparable to raw straw (40–50%), but with higher hydrolysis rates, indicating better accessibility. Rice husks were relatively poorly degradable (<20%), but degradability was improved by weathering in a pig shed. Digestion of spent barley and wheat straw litter was significantly faster (approximately twice the rate) at low (8% solids) than high (14% solids) solids loading. Rice husks degradation kinetics were not significantly influenced by solids concentration. Intrinsic methanogenic activity of heavily soiled spent wheat straw and rice husks bedding was initially poor, but achieved full activity after 40–60 days, indicating that reactor operation without external inoculum may be possible with care.     

Nitrogen transformation during thermophilic composting

Nitrogen transformation of sewage sludge composting without or with rice husks as a bulking agent was investigated. When rice husks were added, nitrogen loss was reduced. Garbage and fish residue were also composted to compare the ammonia volatilization with sewage sludge. Conversion of carbon and that of nitrogen were correlated with the change of the C/N ratio of initial composting materials. Sawdust and bark were found to be efficient bulking agents to reduce the loss of nitrogen due to volatilization of ammonia during composting.     

Germination response to salt in Festuca rubra in a population from a salt marsh

Germination of caryopses and seeds of Festuca rubra L. coll. from wet, dry and dune areas in the salt marsh at Skallingen, Jutland, Denmark, was tested in deionized water and diluted sea water. A strong correlation was found between percentage of germination and the topography of the collection sites. Further it was found that salt tolerance for the most salt tolerant populations, growing on low dunes, was provided partly by the husks rather than only being a characteristic of the seed. In less salt tolerant populations from low and dry areas, husks had no influence on germination percentage in 25% sea water.     

Effects of a bulking agent on the reaction rate of thermophilic sewage sludge composting

The effects of a bulking agent on the reaction rate of sewage sludge composting was investigated quantitatively. Larger amounts of rice husks added as the bulking agent yielded a higher CO₂ evolution rate and a larger number of thermophiles per unit dry mass of raw sludge. The specific CO₂ evolution rate estimated for each thermophile was almost the same, however, irrespective of the mixing ratio of rice husks. Since the calculation showed that the composting solid particles were aerobic, we suggest that the addition of a bulking agent may increase air-solid interfaces where microorganisms can selectively grow to make colonies.     

Comparison between the univariate and multivariate analysis on the partial characterization of the endoglucanase produced in the solid state fermentation by Aspergillus oryzae ATCC 10124

Endoglucanase production by Aspergillus oryzae ATCC 10124 cultivated in rice husks or peanut shells was optimized by experimental design as a function of humidity, time, and temperature. The optimum temperature for the endoglucanase activity was estimated by a univariate analysis (one factor at the time) as 50°C (rice husks) and 60°C (peanut shells), however, by a multivariate analysis (synergism of factors), it was determined a different temperature (56°C) for endoglucanase from peanut shells. For the optimum pH, values determined by univariate and multivariate analysis were 5 and 5.2 (rice husk) and 5 and 7.6 (peanut shells). In addition, the best half-lives were observed at 50°C as 22.8?hr (rice husks) and 7.3?hr (peanut shells), also, 80% of residual activities was obtained between 30 and 50°C for both substrates, and the pH stability was improved at 5–7 (rice hulls) and 6–9 (peanut shells). Both endoglucanases obtained presented different characteristics as a result of the versatility of fungi in different substrates.     

Oecophylla smaragdina ants provide pest control in Australian cacao

Ecosystem service‐driven methods of agricultural production that make optimal use of an ecosystem's natural services are often effective in smallholder crops, leading increases in habitat heterogeneity at large spatial scales that encourage beneficial species. Pollination services in cacao farms can be enhanced through efforts to conserve pollinator habitats, such as adding cacao fruit husks underneath trees to provide habitat and food resources for midge pollinators. However, it remains unclear how this habitat manipulation affects pest densities or biological control. Here, we evaluated the effects of the predaceous ant Oecophylla smaragdina on three major pests of Australian cacao (Helopeltis spp., Amblypelta spp., and Rhyparida nitida) in an Australian cacao farm, in the presence and absence of cacao fruit husks. We also evaluated the effect of O. smaragdina on their potentially plant‐damaging, mutualistic mealybug (Pseudococcidae) partners in the presence and absence of cacao fruit husks. Oecophylla smaragdina reduced the combined densities of Helopeltis spp. and Amblypelta spp., regardless of cacao fruit husk addition. The ants also reduced the densities of R. nitida in the absence of cacao fruit husks, but R. nitida densities were naturally low in the experimental plots that received the addition of cacao fruit husks, regardless of ant presence. In contrast, ants generally increased the densities of mealybugs. These data suggest that O. smaragdina ants provide pest control services for three major insect pests in Australian cacao farms. Furthermore, this control may be compatible with habitat manipulations (i.e., the addition of cacao fruit husks) to improve pollinator habitat.     

Methods of isolating the microflora of moulding, high -moisture barley in partially sealed silos

Fungi were isolated on agar from barley stored at 18–44% moisture content in partially sealed silos by plating out whole, untreated grain as removed from the silos; surface-washed whole grain; surface-washed and then sodium hypochlorite-sterilized whole grain; hypochlorite surface-sterilized, dehusked grains cut vertically and plated with cut surfaces to the agar; husks washed several times after removal and plated as small groups. 5 mg aureomycin/100 ml agar was used to suppress bacterial growth. These methods are compared with others in common use. The isolated species have been tabulated to illustrate the various combinations occurring in grains and in aggregates of husks.     

Effect of stover fraction and storage method on glucose production during enzymatic hydrolysis

One avenue for overcoming the economic challenges associated with the production of ethanol from renewable resources is to reduce the cost of the biomass feedstock. The balance between storage costs and benefits depend on the storage method and composition changes of individual stover fractions. Corn stover from bales stored inside and outside of a barn was separated into an interior and exterior layer after approximately 10 months of storage. The cobs, stalks, and leaves and husks were separated, dried, and ground through a 2 mm screen. Stover, sodium acetate (buffer), cellulase, and deionized water were added to 125 ml flasks. The mixture was held at 50 degrees C in an incubator and samples taken for glucose determination. The average glucose concentration after 60 h of hydrolysis from cobs, leaves and husks, and stalks was 10.5, 9.6, and 3.1 g/l, respectively. Cobs, leaves, and husks produced over 300% more glucose than stalks. Storage outside of the barn decreased the glucose production from individual stover components between 4% and 8%. The effect of stover fraction type on glucose production was significant, while the storage treatment effect was not significant. Fractionation of corn stover may be a method to increase the value of corn stover as a feedstock for glucose production.