Rice Straw Samples Research Articles

Natural contamination of dietary rice straw with zearalenone and urinary zearalenone concentrations in a cattle herd1

The present study was conducted to 1) identify the natural source of feed contamination by zearalenone (ZEN), which was suspected to have caused persistently increased urinary ZEN concentrations in one of our experimental cattle herds, and 2) evaluate the effects of intervention against this source of contamination. As an experimental model, a fattening Japanese Black cattle herd showing persistently increased urinary ZEN concentrations was identified. Urinary ZEN concentrations of cows fed with new rice straw (experimental group, n = 6) vs. cows that continued to feed on the old rice straw (control group, n = 4) were measured at the start (d 1) and at 2 wk (d 14) after the onset of feeding with straw. In addition, the ZEN concentration in feed and water samples was measured by using both the ELISA and HPLC methods. Furthermore, isolation and identification of fungi from rice straw and concentrate feed samples were performed. The urinary ZEN concentration [ZEN (pg/mL)/creatinine (mg/mL) = pg/mg of creatinine] of cows fed with new rice straw was significantly (P < 0.05) less (843 pg/mg of creatinine) than that of cows fed with old rice straw (15,951 pg/mg of creatinine). On both d 1 and 14, the ZEN concentrations of old rice straw were greater than those of new rice straw. In addition, fungal colonies were observed in the culture media that was obtained from the old rice straw suspected of ZEN contamination, but not in the culture media from new rice straw or other feed samples. In conclusion, our field trials clearly indicate that the rice straw fed to the cows was naturally contaminated with ZEN, and that the monitoring of urinary ZEN concentrations could prove to be a useful tool for detecting the exposure of cattle to ZEN contamination at the farm level.

Conversion of rice straw into valuable products by hydrothermal treatment and steam gasification

In order to obtain valuable products such as monosaccharides and hydrogen from rice straw (RS), the two-stage processing, hydrothermal treatment in the first stage and steam gasification in the second stage, was carried out. In the hydrothermal treatment, influence of hydrothermal treatment conditions and pretreatments to the raw RS sample on the product distribution was examined. Maximum yield of monosaccharides from the raw RS sample was 1.1wt.% (C basis), which was obtained by the hydrothermal treatment at 220°C for 5min. A water treatment of raw RS sample was carried out before hydrothermal treatment to increase the yield of monosaccharides, so that 9.4wt.% (C basis) of formic acid was extracted. Furthermore, in the subsequent hydrothermal treatment, the yield of monosaccharides increased up to approximately 4.5wt.% (C basis). Simultaneously, 7.9wt.% (C basis) of acids and furfural and 45.1wt.% (C basis) of other water-soluble products were also formed. In the second stage, conversion of hydrothermal-treated rice straw residue (HT-RSR) into hydrogen was performed by steam gasification using fixed-bed reactor and influence of nickel catalyst was examined. Hydrogen from HT-RSR sample without catalyst was produced above 800°C, while hydrogen from the 7.5wt.% nickel-loaded sample was evolved at lower temperature (500°C). The peak top temperature of the hydrogen evolution was shifted from 850°C for the 1.5wt.% nickel-loaded sample to 750°C for the 7.5wt.% nickel-loaded sample. Total amount of hydrogen evolved from the samples loaded with nickel more than 2wt.% was 50–60mmol/g-RSR and about three times larger than that from HT-RSR sample without catalyst. In addition, e.g. for the 2.3wt.% nickel-loaded sample, the CO, CO2, and other gaseous products were also evolved and their yields were 9.4, 21.1, and 3.1wt.% (C basis), respectively.

Contents of various sources of glucose and fructose in rice straw, a potential feedstock for ethanol production in Japan

The major carbohydrates of rice straw samples were determined in order to evaluate the potential of using rice straw as a feedstock for ethanol production in Japan. Straw samples were harvested by cutting the plants at ground level when the grain was mature and immediately heating or chilling the samples. In all cases, significant amounts (62–303 g kg−1) of soft carbohydrates defined as consisting of glucose, fructose, sucrose, starch and β-1,3-1,4-glucan were detected, in addition to structural carbohydrates (cellulose and xylan). These results indicate that rice straw is a rich source of fermentable sugars from both soft carbohydrates and lignocellulosic portions of the cell wall.

Low diversity of T4-type bacteriophages in applied rice straw, plant residues and rice roots in Japanese rice soils: Estimation from major capsid gene (g23) composition

The present study elucidated the diversity of T4-type bacteriophage communities in applied rice straw and plant residues in soil and rice roots by analyzing the composition of the major capsid gene (g23). The denaturing gradient gel electrophoresis (DGGE) band patterns of g23 fragments were simple and similar to each other without any seasonal change. Twenty-two, twenty and twenty-six g23 clones were obtained from applied rice straw, plant residues and rice roots, respectively. Most of the g23 clones belonged to Paddy Groups I, II, III, V and VIII for rice straw samples, to Paddy Groups I, II and V for plant residue samples, and to Paddy Groups I, II, III, V, VI and VIII for rice root samples, indicating a lower diversity of g23 genes at these sites than in bulk soils. No seasonal variation in the phylogenetic distribution of g23 clones was recorded, in contrast to clear seasonal variations in the bacterial communities at these sites.

EFFECT OF USING PRESSING ON THERMAL CONDUCTIVITY OF RICE STRAW BRICKS

For studying the effect of using pressing on thermal conductivity for rice straw two particle sizes of rice straw were used, large rice straw chops LRSC and Small rice straw chops SRSC. Three moisture contents percentages were used (10, 20 and 30%), three ratios of additives materials (5,10 and 15%) and three formation pressures were used (5.86, 12.37 and 18.51MPa). The thermal conductivity test was carried out on compressed rice straw samples. The results indicated that increasing of deformation pressure lead to decrease the thermal conductivity values for both large and small rice straw chops. The maximum value of thermal conductivity was 0.0362 w/m.°c for large rice straw chops at deformation pressure of 12.37MPa. The minimum value of thermal conductivity was 0.0091 w/m.°c for small rice straw chops at deformation pressure of 18.51MPa.

Use of white rot fungi to improve the feed value of rice straw

Introduction In many countries straw is a main feed for cattle in the winter or in the dry season. However, the feed value of straw is too low to obtain high production levels. One of the main reason for the low feed value of straw is the high lignin level (for rice straw up to 5 %), preventing microbes to access the valuable carbohydrates and causing a low feed intake. In the past many attempts have been published to increase the feed value, using sodium hydroxide, urea and ammonia. Rodrigues et al. (2008) showed that enzymes of fungi are capable of increasing the digestibility of straw in rumen fluid. The aim of the present research was in investigate if growing fungi can be used to unseal the straw and to increase its feed value. Rice straw samples were incubated for different periods with two strains of white rot fungi before being fermented in rumen fluid, using the gas production technique.

Comparison of14C-radioactivity in rice-paddy soil exposed to atmospheric and elevated CO2conditions after14C-carbaryl treatment

This study was performed to investigate if elevated affects the residue pattern of in the soil environment after -carbaryl treatment -carbaryl was applied on the rice plant-grown greenhouse soil exposed to atmospheric and elevated conditions. -radioactivity was measured in the rhizospheric soil and rice straw samples six months after -carbaryl application. Significantly high radioactivity was observed in the soil exposed to atmospheric as compared to that in the soil exposed to elevated C(h. Background level of radioactivity was observed in rice plant samples. These observations suggest the possibility that elevated may affect residual radioactivity of -carbaryl in the soil rather than that in the plant.

Bioethanol Production from Rice Straw in the MAFF Research Project, Japan

AbstractRice straw is among the most abundant herbaceous biomass, and regarded as the central feedstock for bioethanol production in Japan. We found that significant amounts of soft carbohydrates (SCs), defined as carbohydrates readily recoverable by mere extraction from the biomass or brief enzymatic saccharification, exist in rice straw in the form of free glucose, free fructose, sucrose, starch, and β-1,3-1,4-glucan. Based on the finding, we proposed a simple method for bioethanol production from rice straw samples with SCs, by a heat treatment for sterilization and starch gelatinization, followed by simultaneous saccharification/fermentation with Saccharomyces cerevisiae. This method would offer an efficient process for bioethanol production without the aid of harsh thermo/chemical pretreatment step.

Improved enzymatic hydrolysis yield of rice straw using electron beam irradiation pretreatment

Rice straw was irradiated using an electron beam at currents and then hydrolyzed with cellulase and β-glucosidase to produce glucose. The pretreatment by electron beam irradiation (EBI) was found to significantly increase the enzyme digestibility of rice straw. Specifically, when rice straw that was pretreated by EBI at 80 kGy at 0.12 mA and 1 MeV was hydrolyzed with 60 FPU of cellulase and 30 CBU of β-glucosidase, the glucose yield after 132 h of hydrolysis was 52.1% of theoretical maximum. This value was significantly higher than the 22.6% that was obtained when untreated rice straw was used. In addition, SEM analysis of pretreated rice straw revealed that EBI caused apparent damage to the surface of the rice straw. Furthermore, EBI pretreatment was found to increase the crystalline portion of the rice straw. Finally, the crystallinity and enzyme digestibility were found to be strongly correlated between rice straw samples that were pretreated by EBI under different conditions.

Proximate analysis and calorific value estimation of rice straw by near infrared reflectance spectroscopy

AbstractExploitation of straw resources as renewable energy source has attracted increasing interest since the present global energy crisis. Determination of both the proximate analysis and the calorific value are required before the utilisation as a biomass energy source. A total of 172 rice straw samples were collected from 17 provinces of China, and the use of near infrared reflectance spectroscopy was investigated as an alternative rapid method for proximate analysis and calorific value estimation. Different pretreatments and regression methods were examined to obtain optimum calibrations. The constructed models showed satisfactory accuracy and it was concluded that near infrared reflectance spectroscopy can be used as a rapid predictive tool for rice straw analysis.

Variable optimization for biopulping of agricultural residues by Ceriporiopsis subvermispora

Ceriporiopsis subvermispora was used for biochemical pulping of agricultural residues and the results were compared with chemical pulping. Independent variables were screened by Plackett–Burman and optimized by full factorial experimental designs. Biological treatment of rice, wheat and barley straw samples resulted in decrease of the kappa number of these straws by 34%, 21% and 19%, respectively, as compared with controlled samples. The tensile strength and burst factor of hand sheets produced from rice straw were increased by 51% and 33% as compared with the control straws. The tensile strength and burst factor of hand sheets produced from wheat straws were improved by 67% and 36%, these variables for barely straws were 36.7% and 45%, respectively. Although the delignification of wheat and barley straws are not as efficient as chemical process, but the quality of papers produced by biochemical pulping of straws were excellent.

Cyanobacterial communities of rice straw left on the soil surface of a paddy field

To estimate diversity, seasonal variation, and phylogeny of the cyanobacterial communities in rice straw placed in nylon mesh bags and left on the soil surface of a paddy field, total DNA was extracted from straw, amplified by polymerase chain reaction targeting 16S rRNA genes of cyanobacteria, and the amplicons were separated by denaturing gradient gel electrophoresis (DGGE). These DGGE bands were sequenced. The paddy field was under flooded condition after transplanting of rice (Experiment 1) and under drained conditions after harvest (Experiment 2). The residual samples on the soil surface under upland conditions were collected just before spring plowing and were placed again on the soil surface after transplanting under flooded conditions. DGGE band patterns of cyanobacterial communities of rice straw were different under drained conditions, under flooded conditions when fresh rice straw samples were placed (Experiment 1), and under flooded conditions when residual rice straw samples were replaced (Experiment 2), indicating that the communities were influenced by both water regime of the paddy field and the degree of the rice straw decomposition. Sequence analysis of DGGE bands indicated that most of the cyanobacteria in rice straw on the soil surface in the paddy field were filamentous members belonging to Subsections III and IV. Filamentous cyanobacterial cells were observed in rice straw under flooded conditions by epifluorescence microscopy.

The Effect of Pleurotus spp. Fungi on Chemical Composition and in vitro Digestibility of Rice Straw

This study was carried out to test the potentially of using rice straw substrate for the cultivation of four Pleurotus species including Pleurotus florida, Pleurotus djamor, Pleurotus sajor-caju and Pleurotus ostreatus and the effect of these species on the chemical composition, cell wall degradation and digestibility of rice straw. Rice straw soaked in water for 24 h and then it was pasteurized at 100 degrees C for 6 h. Rice straw was inoculated with spawns of four Pleurotus fungi (Pleurotus florida, Pleurotus djamor, Pleurotus sajor-caju and Pleurotus ostreatus) and packed in the plastic bags and incubated in a fermentation chamber at 23-27 degrees C and 75-85% relative humidity. After 60th day, rice straw samples from all groups were taken and analyzed for chemical composition and in vitro digestibility. The data obtained were analyzed according to the complete randomized design model consisting of four treatments plus one control and four replicates. The results of this study showed that fungal treatment increased (p<0.05) the Crude Protein (CP), silica, Ca and P contents of the rice straw but the hemicellulose, Organic Matter (OM), Acid Detergent Fiber (ADF), Neutral Detergent Fiber (NDF) and Acid Detergent Lignin (ADL) contents decreased. However, the ability of the fungi to degrade these components varied among the species. The ability of Pleurotus sajor-caju and Pleurotus ostreatus were higher than the other species in decreasing the hemicellulose, NDF, ADF and ADL contents. The highest Biological Efficiency (BE) was produced by sajor-caju species with 56.02 and the lowest was belong to Pleurotus djamor species with an average 51.17%. All species of fungi incubated on rice straw showed increased (p<0.05) the in vitro dry mater and organic matter digestibility. Rice straw treated with sajor-caju fungus had the highest in vitro dry matter digestibility (IVDMD) and in vitro organic matter digestibility (IVOMD) with 80.10 and 82.18%, respectively. In general this experiment cleared that treatment with sajor-caju can improve the quality of rice straw to be useful feed for ruminant nutrition.

Determination of imazosulfuron persistence in rice crop and soil

Imazosulfuron is a new post-emergence sulfonylurea herbicide. It is highly active at low application rates to control annual and perennial broad-leaf weeds and sedges in rice. There is increasing concerned about the persistence of pesticide residues in soils, crop produce and subsequent contamination of groundwater. Thus persistence of imazosulfuron residues under field condition was evaluated. Imazosulfuron was applied at 30, 40, 50 and 60 a. i. g ha (-1) rates, 4 days after transplanting of rice as post-emergence herbicide. Soil and plant samples treated with imazosulfuron were collected at 60, 90 and 120 days after herbicide application and analyzed for residues. Rice grains and straw samples were sampled at harvest (120 days). Residues of imazosulfuron in soil were not found after 90 and 120 DAS (days after spraying). Rice grains contained 0.006, 0.009 microg g(-1) residues at 50 and 60 g ha (-1) application rates. 0.009 and 0.039 microg g(-1) residues of imazosulfuron were detected at 50 and 60 g/ha rates respectively in rice straw. Residues of imazosulfuron were not detected applied at 30 and 40 g ha(-1) in rice grains and straw, respectively and can be safely applied to the transplanted rice.

Near-infrared analysis of the chemical composition of rice straw

Rapid and accurate determination of chemical composition of rice straw is crucial to predictions of its value and nutritive quality. In this work, calibration models using near-infrared reflectance spectroscopy (NIRS) for determination of rice straw analytical parameters such as total ash, insoluble ash, moisture, cellulose, hemicellulose and Klason lignin were studied using a diverse group of rice straws. The NIRS calibration models for chemical compositions of rice straw were derived by partial least-squares (PLS) regression and prediction of chemical composition of independent rice straw samples showed these models to be rapid and accurate, giving R 2-values higher than 0.85. Such NIRS calibration models are appropriate for the determination of the quality of rice straw samples.

Succession and phylogenetic composition of eubacterial communities in rice straw during decomposition on the surface of paddy field soil

To estimate the bacterial communities in rice straw left on the soil surface of paddy fields, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis was conducted. Rice straw samples were placed on the soil surface in a Japanese paddy field under drained conditions after harvest and under flooded conditions after the transplanting of rice. The residual samples on the soil surface under upland conditions were collected just before spring plowing and were replaced again on the soil surface after transplanting, under flooded conditions. The DGGE patterns of the bacterial communities in rice straw on the surface of paddy field soil were divided into three groups, namely rice straw samples before placement, under drained conditions and under flooded conditions. Sequence analysis of DGGE bands indicated that most of the bacterial members in rice straw during decomposition on the soil surface in the paddy field belonged to Gram-negative bacteria. The bands that commonly existed throughout the periods under flooded and upland conditions were closely related to α-Proteobacteria. The groups of Spirochaetes and δ-Proteobacteria were often observed during flooded periods, although the members of Bacteroidetes, α-Proteobacteria, Gemmatimonadetes and Actinobacteria were also detected under flooded conditions. In contrast, the bands characteristic to the rice straw left on the soil surface of the paddy field under drained conditions belonged to Bacteroidetes and γ-Proteobacteria. This finding clearly indicates that the bacterial communities responsible for rice straw decomposition were determined by the water regime in the paddy field, and various members of Gram-negative bacteria have contributed to the decomposition of rice straw left on the soil surface in a paddy field.

Trace elements accumulation in soil and rice plants irrigated with the contaminated water

We carried out a study to see the effect of contaminated water of Nullah Dek on fine rice paddy and straw yields and trace elements accumulation in different parts of rice plants and soil. A site was selected near the bank of Nullah Dek at Kot Pindi Das in the District of Sheikhupura, Pakistan. The water of this nullah is contaminated by industrial effluents carrying different micronutrients. This water was employed to grow rice crop. Water samples were collected before transplanting and during the season with 15 days interval for analysis from 20 July to 1 November 2002 from a spot near village Shamke. Three fine rice varieties, viz. Super Basmati, Shaheen Basmati and Basmati 2000 were transplanted. These rice varieties were grown up to maturity. Paddy and straw yields data were recorded. Six composite soil samples from three random spots were collected from the experimental site before the start of the study to see the status of trace elements in soil. After the harvest of rice crop, soil, paddy and straw samples were analysed for Zn, Cu, Fe and Mn. The chemical analysis of Nullah Dek water showed that total salts concentration was greater than the safe limit, i.e. electric conductance (EC) > 1.0 dS m −1. Even sodium adsorption ratio (SAR) was very high, but there was no problem of high residual sodium carbonate (RSC). Zn, Cu, Fe and Mn were present but within safe limits. The water of Nullah Dek remained within permissible limits of irrigation from onset of rainy season till 15 October. There was an increase in EC, SAR and trace elements concentrations after 15 October but within safe limits. Soil analysis revealed its saline nature, devoid of sodicity. Among trace elements, the zinc ranged between deficiency (<0.5 mg kg −1) and adequate limits (>1.0 mg kg −1). Copper, Mn and Fe were present in adequate amounts. After the harvest of rice crop there was a slight decrease in pH, EC e and SAR at both the depths, while the concentrations of all trace elements were slightly increased with more in upper layer than the lower layer. Shaheen Basmati produced the maximum paddy yield followed by Basmati 2000 and then Super Basmati. The chemical analysis of paddy samples indicated a sufficient accumulation of zinc (1.68–1.78 mg kg −1), copper (1.38–1.45 mg kg −1), iron (6.12–6.37 mg kg −1) and manganese (2.22–2.42 mg kg −1). Analysis of rice straw also showed sufficient accumulation of zinc (27.50–28.50 mg kg −1), copper (20.0–20.50 mg kg −1), iron (270–280 mg kg −1) and manganese (2.38–2.41 mg kg −1).

Succession and Phylogenetic Profile of Eubacterial Communities in Rice Straw Incorporated into a Rice Field: Estimation by PCR-DGGE Analysis

PCR-DGGE analysis followed by sequencing was conducted to estimate the succession and the phylogenetic profile of the eubacterial communities responsible for the decomposition of rice straw (RS) that was incorporated into a rice field. Leaf sheath and leaf blade parts were separately put in nylon mesh bags, and were placed in the rice field soil under drained conditions during the off-cropping season and under flooded conditions after transplantation of rice. In addition, RS samples that had been placed under drained conditions in the off-cropping season were placed again in flooded rice field soil after transplantation of rice. DGGE patterns of the bacterial communities in the RS samples were classified into two groups, namely leaf sheaths and leaf blades. Principal component analysis of the DGGE patterns revealed the succession along with the duration of placement. These results indicated that the RS part (sheath or blade) mainly determined the structure of the bacterial communities responsible for the RS decomposition, followed by the duration of placement. Sequence analysis of the characteristic DGGE bands indicated that most of the closest relatives associated with the bands belonged to α-, β-, γ-, and δ-Proteobacteria, CFB group, and Spirochaetes. Some bands were closely related to Acidobacteria and Verrucomicrobia. CFB members and α-Proteobacteria predominated commonly in both RS parts, while γ- and δ-Proteobacteria, and Spirochaetes and β-Proteobacteria specifically colonized sheath and blade parts, respectively. In addition, Proteobacteria and CFB members characterized the differences in the bacterial communities under flooded or drained conditions. These results suggest that Proteobacteria, CFB group, and Spirochaetes were responsible for RS decomposition in rice field soil under both flooded and drained conditions.

Predicting digestibility of ammonia fiber explosion (AFEX)-treated rice straw.

The enzymatic digestibility of ammonia fiber explosion (AFEX)-treated rice straw was modeled by statistically correlating the variability of samples to differences in treatment using several different analytical techniques. Lignin content and crystallinity index of cellulose affect enzymatic hydrolysis the most. X-ray diffraction was used to measure the crystallinity index (CrI), while fluorescence and diffuse reflectance infrared (DRIFT) spectroscopy measured the lignin content of the samples. Multivariate analysis was applied to correlate the enzymatic hydrolysis results of the various samples with X-ray diffraction and spectroscopic data. Principal component analysis (PCA) and multilinear regression (MLR) techniques did not accurately predict the digestibility of the rice straw samples. The best correlation (R value of 0.775) was found between the treatment conditions of the AFEX process and the concentration of xylose at 24 h after enzymatic hydrolysis.

The influence of moisture content on polycyclic aromatic hydrocarbons emission during rice straw burning

Open burning was carried out for rice straw samples with moisture contents of 0%, 5%, 10%, 15%, 20%, 25%, and 30%, respectively. The 10 EPA priority polycyclic aromatic hydrocarbons (PAHs) compounds plus naphthacene and perylene were analyzed by means of GC/MS. Total particulate PAHs emission varied between 1 and 38 mg/kg for12 species-specific PAHs. Experimental results showed that water has a depression effect on PAHs emission during rice straw burning. The lowest emission of total particulate PAHs was obtained when rice straw with 15% moisture content was burned. 11 species-specific PAHs showed the lowest emissions within 10–20% moisture content exclusive of naphthacene. In addition, higher emission was observed for intermediate molecular weight compounds such as fluoranthene, pyrene, benz[a]anthracene and chrysene, and relatively lower emission for heavier molecular weight compounds such as perylene, benzo[a]pyrene and dibenz[ah]anthracene.