Ground Rice Straw Research Articles

Do alternative litter Materials Affect performance, Welfare and Immune Response of Broiler Chicks?

Two hundred, one-day-old Cobb broilers were utilized as a part of this analysis. Chicks were examined and weighed on the entry day then, arbitrarily appointed to five litter treatments (20 birds per pen) with two duplicates for every treatment. The litter treatment consists of five different litter types: Wood shavings (WS), Ground rice straw, Ground rice straw + sand, Ground corn stalks straw, and Rice hulls. Behavioral perception was done twice per day, two days a week for six sequential weeks. Body weight (BW) and Feed intake rate per pen were measured each week, from which body weight gain (BWG) and feed conversion ratio (FCR) were calculated. At 42 days of age, welfare indices were measured including fear, stress, fluctuating asymmetry, plumage score, leg health and abnormalities. In addition, some carcass traits, litter quality were surveyed. Immune response against Newcastle diseased virus was determined at 21 and 29 days of age. Mortalities were recorded for every treatment. Our data cleared that birds reared on various litter components exhibited non-significant changes in feeding, drinking, standing, preening and scratching behaviors. While, birds reared on Rice hulls exhibited a significantly higher walking behavior and significantly lowered sitting and dust bathing behaviors. Bedding types had no obvious effect over BW, BWG, FCR and mortality percentages. Welfare indices were not affected by the type of litter substances. The type of the litter did not affect moisture content and compactness score of litter. In contrary, cleanliness score of the litter was worst in Ground rice straw compared to wood shavings. In addition, immune response against Newcastle diseased viruses not affected with types of litter. It concluded that, bedding types affect behaviors of broiler chicks. Ground rice straw, Ground rice straw + sand, Rice hulls and Ground corn stalks straw could be used as alternative bedding materials to wood shavings without affect on birds performance, welfare, health and immune response.

Analysis of ground rice straw with a hydro-textural approach

The lignocellulosic material contained in agricultural residues like straws, represents a resource with many points of biomolecular interest but their extraction is subject to a succession of treatments highly energy-consuming and generating effluents. Due to the strength of the supramolecular structure of the lignocellulosic matrix at various levels, it is difficult to improve the efficiency of separation processes for these materials. The utilization of biomass constituents often requires pretreatment, which is a crucial step in the separation into constituents. The rice straw must firstly be fractionated by grinding, which can also require pretreatment to improve efficiency. The question arises as to how best to identify and model the mechanisms involved in the grinding process with or without pretreatment. The aim of this study was to complete the characterization of the grinding process using a hydro-textural approach applied to biopowders to help with identification of the mechanisms involved. Experimental trials were conducted with rice straw through several milling steps, which led to decreasing particle sizes. The physical properties (density, cohesion, coefficient of friction, ability to flow) were characterized for some of the obtained powders, which were then described with a hydro-textural diagram. The results reveal that the breakdown process led to a “loss of porosity” regardless of the size of the powder particles. The fragmentation seemed to be located in the “zones of stronger porosities”. These structures containing residual water, decreased weakly with grinding. Assuming that the water was located within cells of the straw (intracellular water), given the power law, which correlates compactness to median diameter (d50), we introduced a characteristic size, which corresponds to the physical limit of optimal grinding. Its value, calculated from the model, is nearly equal to the cell wall thickness: limϕ→1d50=ecell.~2μm.

Effects of Ground and Unground Rice Straw on the Yield and Proximate Composition of Groundnut (<i>Arachis hypogeae</i> L.)

A field experiment was carried out to evaluate the influence of ground and unground rice straw application as organic manure on the yield and proximate composition of groundnut seeds, at the University of Ilorin teaching and research farm. The field layout was a split plot Complete Randomized Block Design with four replications. The ground and unground rice straw were in the main plot and different application rates of the rice straw (0; 1,250; 2,500; 3,750 and 5,000 kg /ha) were in the subplots. The results revealed that ground and unground rice straws at 1,250 and 2,500 kg/ha application rates significantly increased (p < 0.05) yield attributes such as pods’ number with a range of 48.33-74.33 pod weight (23.95-42.70), number of seeds (45.67-77.33), seeds’ weight (13.55-25.56 g) and hundred seed weight (34.34-38.05 g) as well as some aspect of proximate composition such as ash content, crude protein and crude fats which ranged between 2.71-2.79%, 31.47-31.56% and 46.61-47.13% respectively, in order of their mention. The forgoing study revealed that ground and unground rice straw applied at the rate of 1,250 and 2,500 kg/ha can serve as an alternative for soil nutrient amendment in groundnut as it ensured a reasonable yield that is able to meet the nutritional needs of man and livestock.

Effects of Ground and Unground Rice Straw on the Yield and Proximate Composition of Groundnut (<i>Arachis hypogeae</i> L.)

Effects of Ground and Unground Rice Straw on the Yield and Proximate Composition of Groundnut (<i>Arachis hypogeae</i> L.)

Characterization of Rice Straw Prehydrolyzates and Their Effect on the Hydrolysis of Model Substrates Using a Commercial endo-Cellulase, β-Glucosidase and Cellulase Cocktail.

Pretreatment and enzymatic saccharification are two major upstream processes that affect the economic feasibility and sustainability of lignocellulosic biofuel production. Cellulase-inhibiting degradation products, generated during dilute acid pretreatment, increase enzyme usage, and therefore, it is essential to mitigate their production. In an attempt to elucidate the most deleterious degradation product to enzymatic hydrolysis, hydrolyzates were generated from rice straw, and their effect on enzyme activity was determined. Ground rice straw was subjected to the following pretreatments having a combined severity factor of 1.75: T1–160 °C, pH 1.7; T2–180 °C, pH 2.25; and T3–220 °C, pH 7.0. The liquid prehydrolyzates were freeze-dried, and their inhibitory effects on the activities of a commercial cellulase cocktail, endo-cellulase, and β-glucosidase were determined using filter paper, carboxymethyl cellulose, and cellobiose, respectively. Addition of 15 g L–1 of T1, T2, or T3 freeze-dried prehydrolyzates resulted in 67%, 57%, and 77% reduction in CMC-ase activity of endo-cellulase, respectively. In the presence of 35 g L–1 of T1, T2, or T3 prehydrolyzates, the filter paper activity of the cellulase cocktail was reduced by 64%, 68%, and 82%, respectively. Characterization of the freeze-dried prehydrolyzates showed that T3 had significantly higher xylo-oligosaccharides and total phenolic content than T2 and T1.

Study of chemical pretreatment and enzymatic saccharification for producing fermentable sugars from rice straw

This study evaluated a cost-effective approach for the conversion of rice straw into fermentable sugars. The composition of rice straw pretreated with 1 % sulfuric acid or 1 % sodium hydroxide solution was compared to rice straw with no chemical pretreatment. Enzymatic saccharification experiments on non-pretreated rice straw (NPRS), pretreated rice straw (PRS), and pretreated rice straw with acid hydrolysate (PRSAH) were conducted in a series of batch reactors. The results indicated that pretreating the rice straw with dilute acid and base increased the cellulose content from 38 % to over 50 %. During enzymatic saccharification, straight aliphatic cellulose was hydrolyzed before branched hemicellulose, and glucose was the major hydrolysis product. The glucose yield was 0.52 g glucose/g for NPRS and was comparable to the yields of 0.50 g glucose/g for PRS and 0.58 g glucose/g for PRSAH. The hydrolysis of rice straw to produce glucose can be described by a first-order reaction with a rate constant of 0.0550 d(-1) for NPRS, 0.0653 d(-1) for PRSAH, and 0.0654 d(-1) for PRS. Overall, the production of fermentable sugars from ground rice straw will be more cost effective if the straw is not pretreated with chemicals.

POSSIBILITY OF USING SOME AGRICULTURAL RESIDUALS IN TOMATO NURSERY PRODUCTION

The main objective of this study is possibility of using some agricultural residuals as plant media to tomato nursery. These residues as ground cotton stalks, ground rice straw and ground corn stalks. Each residual contains different ratio of sand. Also, one sample was 75% peatmoss plus 25% velrmiculite as a control. Laboratory experiments were conducted to quantify real density (g/cm3), bulk density (g/cm3), hydraulic conductivity (cm/min), total porosity (%), and available water (g/g) as affected by different mixtures experimental. The tomato nursery was planted into trays in greenhouse to study some growth parameters as germination ratio, nursery high, plant weight, and leaves number as affected by different mixtures. The results show that in the media of (sand + ground cotton stalks), (sand + ground rice straw), and (sand + ground corn stalks) decreased sand ratio gave an increased in both total porosity and available water, the highest value of total porosity and available water were at mixture of (20% sand + 80%residuals). Also, the highest growth parameter of nursery as nursery weight and nursery high was obtained with the same mixture.

Influence of forage NDF level, source and pelletizing on growth performance, dietary energetics, and characteristics of digestive function for feedlot cattle

One hundred sixty Holstein steers (222±1kg) were used in a 264-d growing-finishing trial to evaluate the influence of forage aNDFom level (40 vs 80g/kg DM) and source [ground forage (alfalfa, sudangrass, and rice straw) or pelletized rice straw] on growth performance. Forage source did not influence (P>0.10) gain efficiency or dietary net energy (NE). Daily weight gain (ADG) and dry matter intake (DMI) were similar (P>0.10) for alfalfa, sudangrass and ground rice straw. Pelletizing rice straw depressed ADG (P<0.01) and DMI (P<0.01). Increasing forage aNDFom decreased gain efficiency (P=0.09), and dietary NE (P=0.04). Four Holstein steers (197kg) with ruminal and proximal duodenal cannulas were used in a 4×4 Latin square design to compare effects of alfalfa vs sudangrass hay at 40 vs 80g/kg of forage aNDFom on digestion. There were no treatment effects on ruminal aNDFom digestion (P>0.10). Ruminal OM digestion was not affected by forage aNDFom level (P=0.96); however, it was greater (P=0.04) for sudangrass vs alfalfa supplemented diets. Microbial efficiency was not affected by forage aNDFom level (P=0.53); however, it was greater (P=0.02) for alfalfa vs sudangrass supplemented diets. Forage source did not affect total tract aNDFom digestion (P=0.86). However, aNDFom digestion was greater (P=0.08) for 80 vs 40g/kg of forage aNDFom. There were interactions between forage aNDFom level and source on total tract OM digestion (P=0.03). With alfalfa, level of forage aNDFom did not affect OM digestion. With sudangrass, increasing forage aNDFom decreased (P<0.05) total tract OM digestion. There were interactions between forage aNDFom level and source on ruminal pH (P=0.05), and acetate:propionate ratio. With alfalfa, increasing forage aNDFom did not affect ruminal pH, but increased acetate:propionate molar ratio. With sudangrass, the increasing forage aNDFom increased ruminal pH, but did not affect VFA molar ratios. Four Holstein steers (189kg) were used in a 4×4 Latin square design to compare effects of ground vs pelletized rice straw at 40 vs 80g/kg of forage aNDFom on digestion. There were no treatment effects (P>0.10) on ruminal OM digestion or microbial efficiency. Ruminal aNDFom digestion was greater (P=0.05) for pelletized vs ground rice straw. There were no treatment effects (P>0.10) on total tract aNDFom digestion. Pelletizing did not affect (P=0.78) total tract OM digestion. Tract OM digestion was greater (P=0.03) for 40 vs 80g/kg of forage aNDFom. Level of forage aNDFom did not affect (P>0.10) ruminal pH or VFA molar proportions. Ruminal pH and acetate:propionate molar ratio were greater (P<0.10) for ground vs pelletized rice straw. Differences among forage sources are minimized when forages are compared at similar levels of forage aNDFom concentration. Compared to ground, pelleted rice straw in finishing diets may produce lower ruminal pH and growth-performance of cattle.

EFFECTS OF ORGANIC AMENDMENTS ON CD, ZN AND CU BIOAVAILABILITY IN SOIL WITH REPEATED PHYTOREMEDIATION BY SEDUM PLUMBIZINCICOLA

Organic materials with different functional groups can be used to enhance metal bioavailability. Traditional organic materials (rice straw and clover) and ethylenediamine disuccinic acid (EDDS) were applied to enhance metal uptake from polluted soil by Sedum plumbizincicola after repeated phytoextraction. Changes in pH, dissolved organic carbon (DOC) and metal concentrations were determined in the soil solution after EDDS application. Amendment of the soil with ground rice straw or ground clove resulted in higher concentrations of Cd only (by factors of 1.92 and 1.71 respectively) in S. plumbizincicola compared to control soil. Treatment with 3 mmol kg−1 EDDS increased all the metals studied by factors of 60.4, 1.67, and 0.27 for Cu, Cd, and Zn, respectively. EDDS significantly increased soil solution DOC and pH and increased soil plant-available metals above the amounts that the plants could take up, resulting in high soil concentrations of soluble metals and high risk of ground water contamination. After repeated phytoremediation of metal contaminated soils the efficiency of metal removal declines as the concentrations of bioavailable metal fractions decline. Traditional organic materials can therefore be much more effective and environmentally friendly amendments than EDDS in enhancing phytoremediation efficiency of Cd contaminated soil.

Physico-mechanical properties of chemically treated polypropylene rice straw bio-composites

Rice straw is causing in many countries severe environmental problems in terms of black clouds caused by the incineration process. Hence, among other reasons, the incorporation of ground rice straw as a filler and reinforcement material for polymers is of advantageous. In this study, Egyptian rice straw was used to reinforce commercial polypropylene and laboratory prepared maleic anhydride-grafted PP with the fill grades between 5wt% and 30wt%. Rice straw PP composites show an improved Young's modulus at increased fill grades, against a decrease in tensile strength. The addition of 1% maleic anhydride per I g of rice straw as a compatibilizing agent caused further amelioration of the fiber/matrix bonding leading to improved mechanical behavior, which was also assessed using scanning electron microscopy. Additional assessments were made via thermographic analysis and density measurements.

Hydrothermal pretreatment of rice straw biomass: A potential and promising method for enhanced methane production

This paper presents the results of an experimental batch methane fermentation (at 37°C mesophilic temperature) study carried out on untreated and pretreated substrates of rice straw using NaOH and hydrothermal pretreatments. 3% NaOH pretreatment was given to ground rice straw biomass for 120h at 37°C and hydrothermal pretreatment was given for 10min at 200°C. It was observed that NaOH addition is a mandatory requirement for maintaining a suitable range of pH and starting the biogas production from hydrothermal pretreated biomass slurry of rice straw. The fed substrate concentrations were maintained at 5% TS (50g TS/L). The study revealed into 140.0L/kg VSa biogas and 59.8L/kg VSa methane from untreated rice straw substrate. However, NaOH pretreated substrate resulted into 184.8L/kg VSa biogas and 74.1L/kg VSa methane. Hydrothermal pretreated followed by 5% NaOH added substrate resulted into highest biogas and methane production yields as 315.9L/kg VSa and 132.7L/kg VSa, respectively. NaOH pretreated substrate showed an increase of 132.0% in biogas production and 123.9% in methane production relative to the untreated substrate. However, the hydrothermal pretreated substrate had resulted into an increase of 225.6% in biogas production and 222.0% in methane production relative to untreated rice straw substrate. Hydrothermal pretreatment provided an accelerated pre-hydrolysis of biomass contents during the treatment process and thereby resulted into enhanced biogas and methane production yields.

Influence of surfactant supplementation and maceration on the feeding value of rice straw in growing-finishing diets for Holstein steers1

Two trials were conducted to evaluate the interaction of the maceration process and surfactant (Tween 80) supplementation on feeding value of rice straw. Treatments were steam-flaked, corn-based diets containing 14% forage (DM basis), which was 1) Sudangrass hay; 2) ground rice straw; 3) ground rice straw plus 0.22% Tween 80; 4) macerated rice straw; and 5) macerated rice straw plus 0.22% Tween 80. In the maceration process, rice straw was passed through 2 sequentially placed pairs of corrugated rolls set at zero tolerance under a ram pressure of 62,050 millibars, similar to a conventional grain roller mill, except that the opposing rolls operated at different speeds (12 and 14 rpm, respectively). Sudangrass hay and rice straw (native and macerated) were ground through a 2.6-cm screen before incorporation into complete mixed diets. In trial 1, 125 Holstein steers (292 +/- 1.7 kg of BW) were used in a 188-d evaluation of the treatment effects on growth performance and carcass characteristics. In trial 2, 5 Holstein steers (224 +/- 3.5 kg of BW) with cannulas in the rumen and proximal duodenum were used in a 5 x 5 Latin square design to evaluate the treatment effects on digestion. There were no interactions between maceration and surfactant on growth or carcass characteristics. Tween 80 did not influence the feeding value of rice straw. Compared with grinding alone, maceration of rice straw increased the carcass-adjusted ADG (6%, P < 0.10), G:F (6%, P < 0.05), and dietary NE (5%, P < 0.05); DMI was similar across treatments. Assuming NE(m) and NE(g) of Sudangrass hay are 1.18 and 0.62 Mcal/kg, the NE(m) and NE(g) were 0.61 and 0.13 Mcal/kg for ground rice straw and 1.21 and 0.65 Mcal/kg for macerated rice straw. There were no treatment interactions on characteristics of digestion. Tween 80 did not influence ruminal or total tract digestion of OM, starch, NDF, or N. Compared with grinding alone, maceration of rice straw increased ruminal digestion of OM (7.7%, P < 0.10) and NDF (30.8%, P < 0.05), and total tract digestion of OM (2.3%, P < 0.10), NDF (21.1%, P < 0.01), and N (3.7%, P < 0.05). Total tract digestion of OM, NDF, starch, and N for the Sudangrass diet corresponded closely with that of the macerated rice straw diets. Maceration increases the feeding value of rice straw to a level similar to that of good-quality (flag stage of maturity) Sudangrass hay, which is attributable to increased OM and NDF digestion. Effects of surfactant supplementation on growth performance and digestion are not appreciable.

A sustainable approach to the recycling of rice straw through pelletization and controlled burning

A technique for controlled burning of rice straw is presented. It relies on well-designed rice straw pellets to be burned in fluidized bed. The developed pellets have high burning rate, no fly ashes emissions and minimum bed fouling. The pellets are manufactured from ground rice straw in a disc pelletizer with the aid of bonding and suitable additive materials. The pellets are tested under controlled conditions in a test rig, which represents a single pellet fluidized bed. It is equipped with a nitrogen gun to eject the pellet and freeze the reaction at any predetermined time during combustion. The ejected pellets are weighed as well as elementary analyzed for both carbon and hydrogen, to calculate the burning rate as well as the combustion efficiency, respectively. The effect of several parameters has been evaluated including straw particle size, pellet size, type and concentration of bonding material as well as anti-sintering additives. Also, the pellets’ mechanical characteristics have been evaluated. It has been found that char combustion phase represents the controlling phase of the pellet combustion. The burning rate is higher as the void fraction of the pellet is higher. Starch showed better combustion and mechanical characteristics out of the five tested bonding materials. Adding kaolin to the pellets results in improving the sintering characteristics of the pellets. The experimental results were compared with two combustion models: the oxygen diffusion controlled and the kinetic-diffusion models. It has been found that oxygen diffusion controlled model more accurately simulates the combustion of the pellet during its char combustion phase. The model has been used to evaluate the effect of some operational parameters on the pellet combustion characteristics such as bed temperature, gas flow and oxygen concentration.

Bioconversion of Straw into Improved Fodder: Preliminary Treatment of Rice Straw Using Mechanical, Chemical and/or Gamma Irradiation

Crude protein (CP) content of mechanically ground rice straw into small particles by an electric grinder and reducing value (RV) and soluble protein (SP) in the culture filtrate were lower than that of the chopped straw into 5~6 cm lengths when both ground and chopped straws were fermented with Aspergillus ochraceus, A. terreus or Trichoderma koningii, at steady conditions. The reduction rate of RV, SP and CP was 22.2, 2.4, 7.3%; 9.1, 4.9, 8.5% or 0.0, 0.0, 3.6% for the three fungi, respectively. Chemical pretreatment of straw by soaking in NH4OH for a day caused significant increase in CP of the fermented straw than the other alkali and acidic pretreatments. Gamma irradiation pretreatment of dry and wet straw with water, specially at higher doses, 100, 200 or 500 kGy, caused significant increase in RV and SP as CP in the fermented straw by any of these fungi. Chemical-physical combination pretreatment of rice straw reduced the applied dose of gamma irradiation required for increasing fermentable ability of fungi from 500 kGy to 10 kGy with approximately the same results. Significant increases in RV and SP of fermented straw generally occurred as the dose of gamma irradiation for pretreated straw, which combined with NH4OH, gradually rose. Whereas, the increase percentage in CP of fermented straw that was pretreated by NH4OH-10 kGy was 12.4%, 15.4% or 8.6% for A. ochraceus, A. terreus or 7. koningii, respectively.

Effect of pelletizing on the feeding value of rice straw in steam-flaked corn growing-finishing diets for feedlot cattle

Trial 1. Three cannulated crossbred steers were used to compare the effects of ground versus pelletized rice straw on characteristics of digestion. Treatments consisted of a steam-flaked corn-based diet containing 120 g/kg sudangrass (SG, positive control), ground rice straw (GRS) or pelletized rice straw (PRS). Ruminal digestion of organic matter was similar across treatments ( P<0.10). Ruminal digestion of neutral detergent fiber was low, averaging 140 g/kg, and not affected ( P>0.10) by forage source. Ruminal starch digestion was lower (5%; P<0.05) for sudangrass than for rice straw diets, and greater (8%, P<0.01) for pelletized versus ground straw. Ruminal microbial efficiency was greater (9.7%; P<0.05) for ground than for pelletized rice straw. Total tract digestion of dry matter was greater (3%, P<0.10) for sudangrass than for rice straw treatments and NDF digestion was lower (26%; P<0.05) for rice straw than for sudangrass diets. Total tract starch digestion was greater (2%, P<0.01) for pelletized than for ground rice straw diets, due largely to greater ruminal starch digestion. Treatment effects were numerically similar for ground sudangrass and ground rice straw diets. Pelletized rice straw increased ( P<0.05) ruminal total volatile fatty acid (VFA) and propionate concentrations by 24 and 47% respectively, and decreased ruminal pH (9%, P<0.05), ruminal acetate:propionate molar ratio (27%, P<0.05), and estimated methane production (28%, P<0.05). Trial 2. Ninety crossbred yearling steers were used in a 112 day finishing trial to evaluate the influence of pelletizing on the feeding value of rice straw. Treatments were the same as Trial 1. Substituting ground rice straw for sudangrass had no detrimental effects ( P>0.10) on energy intake or average daily gain (ADG). However, DMI and ADG were greater (11%, P<0.05, and 12%, P<0.10, respectively) for ground than for pelletized rice straw supplemented diets. There were no treatment effects ( P>0.10) on dressing percentage, which had a carcass to live weight ratio averaging 0.642. Steers fed the sudangrass diet had a lower yield grade (16%; P<0.01), marbling score (13%; P<0.05), and fat thickness (15%; P<0.10) than those fed the rice straw diets. Feeding pelletized straw reduced marbling score (10%, P<0.10), and fat thickness (20%; P<0.10) when compared with ground rice straw. As expected, NE m and NE g were greater (5%; P<0.01) for sudangrass than for rice straw diets. Pelletizing rice straw did not decrease ( P=0.56) the dietary net energy (NE) value of the rice straw supplemented diets. Thus, the difference in ADG due to feeding ground versus pelletized rice straw is attributable solely to treatment effects on DMI. We conclude that at lower levels of rice straw inclusion (<150 g/kg) fed to steers in growing-finishing diets, pelletizing the straw may reduce intake and gain through a satiety response mechanism, possibly associated with increased propionate production.

Enhancement of Enzymatic Hydrolysis of Lignocellulosic Wastes by Microwave Pretreatment Under Atmospheric Pressure

A technique to improve enzymatic hydrolysis of lignocellulosic wastes by microwave pretreatment under atmospheric pressure was developed. Ground rice straw or sugar cane bagasse immersed in a glycerine medium with small amounts of water, was treated with 240 W of microwave irradiation for 10 min at atmospheric pressure. A temperature of about 200°C could be reached in this medium without high pressure build up. More than twice the amount of reducing sugars was produced from enzyme saccharification utilizing the microwave pretreatment, compared with no pretreatment. The microwave pretreatment which achieves high temperatures at atmospheric pressure provides some advantages over a steam explosion process which requires high pressure and a subsequent sudden pressure drop.

Over-production of β-glucosidase by Aspergillus niger mutant from lignocellulosic biomass

The maximum yield of β-glucosidase by A. niger KK2 mutant, grown on the basal medium for 7 days, was 514 I U g−1 ground rice straw, and was about twice those obtained from wheat straw or bran by previous researchers. Optimal activity of β-glucosidase was at 60–70 °C and pH 4.8.

Production of cellulase and xylanase in a bubble column using immobilizedAspergillus Niger KKS

Aspergillus niger KKS, isolated from a farmland near Suwon, was immobilized on Celite and polyurethane foams. Enzyme activities produced by the immobilized cell system in a bubble column were higher than that of shake-flask culture. The enzyme productivities were twice as high. beta-Glucosidase, beta-xylosidase, and xylanase activities obtained in a bubble column were significant when the ground rice straw was used as a substrate.

Factors affecting methane production under rice

To understand why atmospheric methane is increasing worldwide, accurate estimates are needed of the global input from rice fields. We report greenhouse and laboratory studies over three growing seasons to isolate and control factors that might affect methane emission from rice paddies, including soil texture, added exogenous organic matter (OM), nitrogen and sulfate ion, and water management. Without added OM, methane production was relatively low, increasing during the growing season, and continuing after harvest, provided the soil remained water‐logged. If ground rice straw was added to the soil prior to planting, methane production began shortly after flooding, with an initial burst of the gas after 3 to 5 weeks, and then a gradual increase to a second peak later in the season (and after harvest), with rates considerably higher than in treatments without added OM.

Effect of Dietary Fiber on Utilization of Energy and Protein in Chickens.

Cellulose powder, pectin, alginic acid and finely ground rice straw were used as the dietary fiber source. Experimental diets were composed of soybean protein, corn starch, cornoil and some minor ingredients with 10% of above mentioned dietary fibers. A total of 8 colostomized White Leghorn male chickens were forced-fed 70 g/day of the experimental diets for 7 days alternatively so as to make a 4×4 Latin-square design. The amount of fresh feces was significantly higher in the pectin and alginic acid diets, however, water content in the feces was also higher in these diets. Consequently, the dry matter excreted were not different between the treatments, which resulted in no difference of dry matter and energy digestibilities among the diets. Protein digestibility was higher in the cellulose diet and lower in the pectin diet due to the significant difference in fecal nitrogen excretion. Urinary nitrogen was very low in the cellulose diet, and reflecting it biological value of protein was higher in the cellulose diet. Acid detergent fiber was digested by chickens to a small extent, but hemicelluloses seemed to be not digested, because the digestibility of neutral detergent fiber was the same to that of acid detergent fiber.