Supplementation Of Nitrogen Sources Research Articles

Evaluation of composts as biofilter packing material for treatment of gaseous p-xylene

Composts are often employed as a packing material of a biofilter for treating gaseous streams contaminated with volatile organic compounds or malodorous chemicals. In order to select a good packing material for a biofilter, two commercially available composts in Korea, pig manure compost (PMC) and food waste compost (FWC), were studied during the treatment of gaseous p-xylene. The composts were used as purchased or after washed with water to remove water-soluble nutrients and microorganisms on the compost surface. Washed composts exhibited a shorter start-up period for a biofilter to reach a high and steady degradation level of p-xylene. Nitrogen limitation was experienced when a biofilter was operated without adding a supplemental nitrogen source. The soluble nitrogen content was initially higher in PMC than in FWC, but the latter had a higher content of insoluble nitrogen and a lower activity of the nitrification which converts NH 3-N to NO 3-N. The biofilter packed with FWC yielded a lower loss of nitrogen as leachate and exhibited a more stable performance for a longer period of 150 days with the maximal elimination capacity of 21 g p-xylene m −3 h −1.

Tannase production by Paecilomyces variotii

Surface response methodology was applied to the optimization of the laboratory scale production of tannase using a lineage of Paecilomyces variotii. A preliminary study was conducted to evaluate the effects of variables, including temperature (°C), residue (%) (coffee husk:wheat bran), tannic acid (%) and salt solutions (%) on the production of tannase during 3, 5 and 7 days of fermentation. Among these variables, temperature, residues and tannic acid had significant effects on tannase production. The variables were optimized using surface response methodology. The best conditions for tannase production were: temperature (29–34 °C); tannic acid (8.5–14%); % residue (coffee husk:wheat bran 50:50) and incubation time of 5 days. The supplementation of external nitrogen and carbon sources at 0.4%, 0.8% and 1.2% concentration on tannase production were studied in the optimized medium. Three different nitrogen sources included yeast extract, ammonia nitrate and sodium nitrate along with carbon source (starch) were studied. Only ammonia nitrate showed a significant effect on tannase production. After the optimization process, the tannase activity increased 8.6-fold.

Laccase activities of a soil fungus Penicillium simplicissimum in relation to lignin degradation

The laccase activities of Penicillium simplicissimum H5 during solid-state fermentation with rice straw were studied. Degradation of lignocellulose was also followed. Results showed that all supplemental carbon sources inhibited the laccase activity in different degrees, while suitable concentrations of supplemental nitrogen sources remarkably enhanced the laccase activity. The enhancement of activity by the ordinary laccase inducers 2, 2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and xylidine was not observed in this study. Lignocellulose degradation was improved when laccase activity was relatively low, suggesting a polymerizing function of laccase in lignin degradation by P. simplicissimum.

Statistical screening of medium components by Plackett–Burman design for lactic acid production by Lactobacillus sp. KCP01 using date juice

Statistical screening of media components for production of lactic acid by Lactobacillus sp. KCP01 using date juice as a sugar source was carried out by Plackett–Burman design. Date juice at 5% sugar concentration when used alone showed 2.6 g/l of lactic acid production. Increase in lactic acid production (15.1 g/l) was observed with supplementation of salts and organic nitrogen sources of MRS medium and after optimization of pH and temperature using date juice as a C-source. Plackett–Burman design showed peptone, K 2HPO 4, sodium acetate and date juice as significant components influencing the lactic acid production.

Chitosan from Syncephalastrum racemosum Using Sugar Cane Substrates as Inexpensive Carbon Sources

A strain of Syncephalastrum racemosum isolated from herbivores feces was studied for chitosan production using sugar cane substrates, such as juice or molasses, from Northeast Brazil. S. racemosus was batch grown in shake flasks over 5 days using sugar cane juice or molasses as carbon source. The effect of supplementary nitrogen source was studied by supplying medium with yeast extract or ammonium sulphate. The highest yield of the biopolymer (30 mg chitosan. g−1 sucrose) was obtained using sugar cane juice (21 g sucrose. L−1) plus 0.3% yeast extract. Batch fermentation in a 5-L bioreactor using the same medium, increased the yield to 50 mg chitosan. g−1 sucrose. Chitosan extracted from S. racemosus cultured in sugar cane juice medium showed a low degree of acetylation with a high D-glucosamine content.

Characterization of humic acids extracted from sewage sludge-amended oxisols by electron paramagnetic resonance

In tropical soils, the high turnover rate and mineralization of organic matter (OM) associated with intensive agricultural use, generally leads to faster soil degradation than that observed in temperate climatic zones. The application of sewage sludge to the soils is one proposed method of maintaining soil organic matter, and is also an alternative method of disposing of this waste product. As well as containing large quantities of OM, sludge is also a significant source of supplementary nitrogen, phosphorus and other essential nutrients for plant growth. However, it is necessary to understand the qualitative and quantitative changes that take place in the OM in soil treated with sewage sludge. The approach of the present study was intended to identify possible structural changes caused by sewage sludge applications on soil humic acids (HAs). The HAs extracted from a Typic Achrortox under sewage sludge applications were characterized by electron paramagnetic resonance (EPR) spectroscopy. The soil samples were collected from a field experiment designed to evaluate the effects of different doses of sewage sludge on corn growth and development in Brazil. The sewage sludge originated from urban waste treated at the sewage sludge treatment station in the city of Franca, state of Sao Paulo, Brazil. The following soil treatments were studied: control (non-cultivated soil under natural vegetation (NC)), control soil amended with NPK (conventional corn fertilization) and four treatments N1, N2, N4 and N8 with applications of 3.5, 7, 14 and 28 Mg ha −1 of sewage sludge (dry matter), respectively. HAs were extracted from the surface layer using the methodology of the International Humic Substance Society (IHSS). Fe 3+ and VO 2+ ions complexed with HAs, and also semiquinone-type free radical (SFR) at concentrations of approximately 2.0 × 10 18 spins g −1 HA were identified in EPR spectra. The levels of SFR were lower for treatments where the applied sewage sludge doses were equivalent to four and eight times the normal doses of N mineral fertilization, reaching values of 1.7 × 10 18 and 1.24 × 10 18 spins g −1 HA, respectively. The observed decrease in SFR content as sewage sludge dose was increased, was probably associated with the incorporation of less aromatic components into HAs originating from the sewage sludge.

Green gram husk—an inexpensive substrate for alkaline protease production by Bacillus sp. in solid-state fermentation

Alkaline protease production under solid-state fermentation was investigated using isolated alkalophilic Bacillus sp. Among all agro-industrial waste material evaluated, green gram husk supported maximum protease production. Solid material particle size regulated the enzyme production and yield was improved with the supplementation of carbon and nitrogen sources to the solid medium. Optimum enzyme production was achieved with 1.5% maltose and 2.0% yeast extract with 371% increase than control. Glucose did not repressed enzyme production but inorganic nitrogen sources showed little negative impact. The physiological fermentation factors such as pH of the medium (pH 9.0), moisture content (140%), incubation time (60 h) and inoculum level played a vital role in alkaline protease production. The enzyme production was found to be associated with the growth of the bacterial culture.

High ambient ammonia promotes growth in a ureogenic goby, Mugilogobius abei

Mugilogobius abei has the ability to produce large amounts of urea when exposed to high ambient ammonia. Despite this metabolically costly approach, and reports of growth inhibition effects of ammonia on fish, M. abei exposed to ammonia shows no adverse effects on growth. To investigate this observation the growth of M. abei was measured at room temperatures for 8 weeks at a constant ration level under solitary and grouped conditions, in 20% SW with or without (control) 2 mM NH(4)Cl. Furthermore, pituitary mRNA levels of growth hormone, oxygen consumption, incorporation of external (15)N-ammonia into amino acid and protein fractions as well as behavioral activities were also examined. The specific growth rates of ammonia-exposed fish under grouped condition over the 8 weeks were significantly higher than those of control, while those rates under solitary condition were not significantly different between the treatments. The pituitary of ammonia-exposed fish had higher growth hormone mRNA than in control fish. The use of (15)N isotope revealed that M. abei can actively use external ammonia as a supplementary nitrogen source. Oxygen consumption of ammonia-exposed fish was significantly lower than that of control fish. Locomotor activity and aggressive behavior under grouped condition were significantly reduced in ammonia-exposed fish as compared to those of control. These combined alterations in the ammonia-exposed fish may result in the higher growth rates.

Bioconversion of Plant Raw Materials in Value-Added Products by Lentinus edodes (Berk.) Singer and Pleurotus spp.

Lentinus edodes and Pleurotus spp. were compared for their ability to produce extracellular hydrolytic and oxidative enzymes in solid-state fermentation (SSF) and submerged fermentation (SF) of different lignocellulosic agroindustrial wastes. From received data the following conclusions were drawn.First, fungi cultivation in identical culture conditions reveals wide differences among both species and strains of the same species. For example, in SSF of tree leaves by fungi of genus Pleurotus, endoglucanase activity varied from 0.5 U mL−1 (P. ostreatus IBB 8) to 26.0 U mL−1 (P. ostreatus (Jacq.: Fr.)P. Kumm. IBB 2191), whereas xylanase activity varied from 3.1 U mL−1 (P. tuberregium (Rumph.: Fr.) Singer IBB 624) to 43.7 U mL−1 (P. ostreatus 2175).Second, the nature and chemical composition of lignocellulosic material is one of the main factors determining the expression of fungi lignocellulolytic potential as well as the ratio of individual enzymes in lignocellulolytic system. For example, P. dryinus (Pers.: Fr.) P.Kumm. IBB 903 maximal laccase activity was equal to 119,195, 794, and 4103 U/L−1 in SF of milled tree leaves, banana, apple, and mandarin peels, respectively.Third, the effect of lignocellulosic substrate concentration on enzyme synthesis varies in dependence on fungi peculiarities. Whereas P. dryinus IBB 903 hydrolytic and oxidative enzyme activity increased by 3−8 times with the elevation of mandarin peels or tree leaves concentration from 1 to 4−6%, in the case of P. tuberregium IBB 624 the lowest substrate concentration was sufficient to ensure the maximal production of laccase, cellulase, and xylanase by this mushroom.Fourth, the data proved that most plant raw materials tested contained sufficient nitrogen concentrations to ensure both mushroom growth and enzyme synthesis. However, depending on fungi and lignocellulosic substrate, supplementation of additional nitrogen sources in the medium effects the yield of lignocellulolytic enzymes. It is worth noting that in most cases only increased fungi growth and biomass in the presence of additional nitrogen accounts for the higher level of laccase activity.Fifth, supplementing the culture medium by stimulators (xylidine, copper, or manganese) increased the yield of P. dryinus IBB 903 ligninolytic enzymes or caused their early and rapid accumulation in culture liquid.The investigation of fruiting body yield and hydrolytic and oxidative enzyme accumulation during bioconversion of different lignocellulosic wastes by Pleurotus spp. and Lentinus edodes showed that biological efficiency reached 86−118% and 81−116%, depending on growth substrate and medium used to soak the substrate.Cultivation of two strains of P. ostreatus on wheat straw and tree leaves as growth substrates clearly showed physiological and biochemical changes taking place during mushroom growth and development on plant raw materials. Mushroom cellulases and xylanase activity appeared to be very low during the vegetative phase of substrate colonization by mycelia. Their activity sharply rose with the appearance of primordia and reached their maximum at a stage of matured fruiting bodies. After fruit bodies were harvested, when the culture was in vegetative phase of development, the activity of these enzymes decreased again. In contrast, mushroom cultures were distinguished by high laccase and MnP activity during substrate colonization. The activity of both enzymes decreased at stages of primordia appearance and fruiting bodies maturation. However, when the culture enters the second vegetative phase (5 days after the fruit bodies were harvested), laccase and MnP activities increased again.The study of lignocellulolytic enzyme activity of L. edodes in mushroom cultivation on wheat straw and tree leaves showed the same regularities that were revealed in cultivation of Pleurotus spp. with insignificant variations. The vegetative growth of these edible mushrooms is characterized by comparatively low activity of polysaccharases and high activity of ligninolytic enzymes. During the period of fruiting body formation, when the mushroom growth requires large quantities of plastic materials and energy, the secretion of cellulases and xylanase sharply increases to accelerate polysaccharide hydrolysis. In contrast, ligninolytic enzyme production appears, to some extent, is repressed to prevent the expenditure of constructive materials and energy.Finally, the data on mushroom enzyme activity show that residual spent substrate may become a cheap source of lignocellulolytic enzymes for several biotechnological applications.

Microbial Synthesis of Chitinase in Solid Cultures and Its Potential as a Biocontrol Agent Against Phytopathogenic Fungus <I>Colletotrichum gloeosporioides</I>

Antifungal activity of chitinase can be effectively utilized in biologic pest control strategies. Because solid-state cultivation has been termed a cost-effective means for fungal growth and metabolite production, chitinase production by Trichoderma harzianum was studied using wheat bran-based solid medium containing 1% colloidal chitin. Chitinase synthesis was found to be growth associated because maximum enzyme (5.4 U/g of dry substrate) and biomass production occurred at 72 h. Substrate moisture had a critical impact on chitinase production; five grams of medium having an initial moisture content of 68.4% when incubated for 72 h increased the enzyme yield to 9.3 U/g of dry substrate. Optimization of colloidal chitin concentration showed that improvements in chitinase yield and maximum activity were attained with a 2% (w/w) concentration. Supplementation of additional nitrogen sources also influenced enzyme production, and the best yield was obtained with yeast extract. The effect of crude chitinase on hyphal morphology of the phytopathogenic fungus Colletotrichum gloeosporioides was swelling as well as lysis of hyphal wall, depending on the age of the mycelium. Studies of pH and thermal stability showed that crude culture filtrate was active over pH 4.0-6.0 and retained about 48.2% activity after 40 min of incubation at 40 degrees C.

Feeding of grainless diets containing different nitrogen sources to crossbred growing bulls: effects on rumen fermentation pattern, microbial enzyme activity and ciliate protozoa population

The effect of feeding grainless concentrates containing different supplemental nitrogen sources along with wheat straw-based diets was studied on rumen fermentation pattern, microbial enzyme activity and protozoa population. For the purpose five fistulated 18 months aged crossbred bulls ( Bos indicus × Bos taurus) were used in a 5 × 5 Latin square design. The animal fed the control diet, received barley 300 g/kg dry matter (DM) in the concentrate mixture (CM1) as a source of grain, whereas other concentrates contained only wheat bran (CM2) or wheat bran supplemented with 25 g urea (CM3), 215 g groundnut cake (GNC) (CM4) or 270 g mustard oil cake (MOC) (CM5)/kg DM, as a source of supplemental nitrogen. The bulls were fed concentrate mixtures at 1 kg/100 kg of their body weight. Each feeding period lasted 21 days followed by rumen liquor collection. Neither the presence of barley nor the nitrogen from different sources in the concentrate mixture did influence the daily dry matter intake (DMI) by the bulls. The DMI per unit of body weight was similar in all the groups. Feeding of barley-based concentrate (CM1) and GNC supplemented grainless diet (CM4) significantly decreased the rumen pH at 4–6 h post-feeding. The total volatile fatty acid (VFA) concentration was the highest ( P < 0.01) in animals fed CM1 and higher ( P < 0.05) on CM4 than on CM5. However, the dietary treatments did not influence the molar proportion of acetate, propionate and butyrate. Supplementation of urea in the concentrate mixture (CM3) resulted in the highest ( P < 0.01) ruminal ammonia-N (NH 3-N) concentration. The ruminal total-nitrogen concentration was the highest ( P < 0.01) in animals fed on CM1 and higher ( P < 0.05) on CM4 than on CM5. In the strained rumen liquor (SRL) α-amylase activity was increased significantly when the animals fed CM1. The endoglucanase activity was significantly decreased ( P < 0.05) in animals fed on CM4 and CM5 as compared to that of CM1 fed bulls. Supplementation of oil cakes or urea to the wheat bran-based grainless concentrates significantly increased the protease activity. Urease activity was significantly increased in response to the dietary urea. Total ciliate population did not differ in SRL of animals fed on CM1, CM2 and CM4, which were significantly higher to that of those fed on CM3 or CM5. Addition of MOC seemed to depress the overall rumen fermentation. The rumen fermentation pattern of bulls fed wheat bran-based grainless concentrate mixture with supplemental nitrogen, urea or oil cakes, was almost similar to that of those fed on grain-based concentrate at 1 kg/100 kg of body weight, when wheat straw used as basal roughage.

Enrichment and identification of bacteria capable of reducing chemical oxygen demand of anaerobically treated molasses spent wash.

The aim of this study was to isolate and identify bacterial strains capable of using recalcitrant compounds of molasses spent wash as sole carbon source from the soils of abandoned sites of distillery effluent discharge and characterize their ability of reducing the chemical oxygen demand (COD) of the spent wash. The isolates were grouped into six haplotypes by amplified ribosomal DNA restriction analysis (ARDRA) and BOX-PCR. The phylogenetic position of the representatives of the six main haplotypes strains was determined by 16S rDNA sequencing. They showed maximum similarity to six genera viz. Pseudomonas, Enterobacter, Stenotrophomonas, Aeromonas, Acinetobacter and Klebsiella. The extent of COD (44%) reduced collectively by the six strains was equal to that reduced individually by Aeromonas, Acinetobacter, Pseudomonas and Enterobacter. With spent wash as sole carbon source, the COD reducing strains grew faster at 37 degrees C than 30 degrees C. Bacterial strains capable of degrading some of the recalcitrant compounds of anaerobically digested molasses spent wash can be isolated from the soils of abandoned sites of distillery effluent discharge. Biostimulation of these bacteria, which can degrade 44% of the carbon compounds of anaerobically digested molasses spent wash can be achieved by nitrogen fertilization and relatively higher temperature. Supplementation of nitrogen source and controlling the temperature can be used in evolving strategies for in situ bioremediation of anaerobically digested spent wash from distilleries.

Extracellular chitinase production by Trichoderma harzianum in submerged fermentation.

Extra-cellular chitinase production by a chitinolytic fungus Trichoderma harzianum TUBF 966 using submerged fermentation was studied. Colloidal chitin (1.5% w/v) was used as sole carbon source. Maximum chitinase production (14.7 U/ml) was obtained when fermentation was carried out at 30 degrees C for 96 h using 72 h old mycelium in a medium containing colloidal chitin 1.5% (w/v) as carbon source and 0.42 (% w/v) peptone as nitrogen source (pH 5.5). Supplementation of additional carbon sources (0.75% w/v) showed no further enhancement in chitinase production while supplementation of nitrogen sources (0.42% w/v) such as peptone and tryptone in the fermentation medium showed a marked increase in production. The process parameters that controlled chitinase production by the fungus were studied and presented here.

Expression of a novel regenerating gene product, Reg IV, by high density fermentation in Pichia pastoris: production, purification, and characterization

Human regenerating (Reg) gene products are regionally expressed by gut-derived tissues, and are markedly up-regulated in cancer and in diseases characterized by mucosal injury. We recently identified Reg IV, a novel regenerating gene product that is uniquely expressed by the normal distal gastrointestinal mucosa. The function remains poorly understood due to the lack of significant purified Reg IV for biochemical and functional studies. Recombinant human Reg IV was efficiently expressed under the control of the AOX1 gene promoter in Pichia pastoris using the Mut S strain KM71H. We describe the unique conditions that are required for efficient production of Reg IV protein in high density fermentation. Optimal protein expression was obtained by reduction of the fermentation temperature and addition of casamino acids as a supplemental nitrogen source and to minimize the activity of yeast produced proteases. Recombinant Reg IV protein was purified by tangential flow filtration and reverse phase chromatography. The purified protein was characterized by amino terminus sequence analysis and MALDI-TOFMS showing that the engineered protein had the expected sequence and molecular weight without secondary modification. Recombinant Reg IV was further characterized by specific monoclonal and polyclonal reagents that function for Western blot analysis and for immunolocalization studies.

Effects of supplemental protein removal on total and acid-resistant E. coli, total coliforms, and performance in finishing steers (2003)

Fifty-four crossbred finishing steers were used to measure the effects of reducing supplemental protein (nitrogen) on feedlot performance and fecal shedding of acidresistant Escherichia coli and total coliform bacteria. A control diet (15.0% crude protein; high protein) was compared to a low protein diet (8.9% crude protein; low protein) from which supplemental nitrogen sources (urea and soybean meal) were removed for the last 8 days of the feeding period. Fecal E. coli and coliform populations were measured prior to harvest. Removal of supplemental nitrogen from feedlot cattle diets did not substantially reduce populations of acid-resistant fecal E. coli and coliforms. Fecal pH tended to be lower (P=0.11) and the molar percentage of fecal isobutyrate and valerate were lower (P<0.05) for steers receiving low protein diets, but total fecal volatile fatty acid concentrations were not affected by dietary treatment. Dry matter intake tended to be lower (P<0.10) for steers fed low protein diets, whereas daily gains, feed:gain, final weights, dressing percentages, and carcass characteristics were similar for cattle fed low and high protein diets.

Effect of corn processing on starch digestion and bacterial crude protein flow in finishing cattle.

Six ruminally and duodenally cannulated yearling steers (523 kg) were used in a replicated 3 x 3 Latin square design experiment to study the effects of corn processing on nutrient digestion, bacterial CP production, and ruminal fermentation. Dietary treatments consisted of 90% concentrate diets that were based on dry-rolled (DRC), high-moisture (HMC), or steam-flaked (SFC) corn. Each diet contained 2.0% urea (DM basis) as the sole source of supplemental nitrogen. Each period lasted 17 d, with d 1 through 14 for diet adaptation and d 15 through 17 for fecal, duodenal, and ruminal sampling. Dry matter and OM intakes were similar for DRC and SFC but were approximately 15% higher (P < 0.05) for HMC. True ruminal OM digestibilities were 18 and 10% greater (P < 0.05) for HMC than for DRC or SFC, respectively. Ruminal starch digestibilities were similar between HMC and SFC and were approximately 19% greater (P < 0.05) than DRC. Postruminal OM digestibility was similar among treatments; however, postruminal starch digestibility was 15% greater (P < 0.05) for SFC than for DRC or HMC, which were similar. Total-tract DM and OM digestibilities were similar between HMC and SFC and were 4% greater (P < 0.05) than DRC. Likewise, total-tract starch digestibilities were similar between HMC and SFC and were 3% greater (P < 0.05) than DRC. Bacterial CP flow to the duodenum was 29% greater (P < 0.05) for HMC than for DRC or SFC, which were similar. Bacterial N efficiencies were similar among treatments. Based on bacterial CP flow from the rumen, we estimate that dietary DIP requirements are approximately 12% higher for HMC-based diets than for DRC or SFC-based diets, which were similar.

Microbial hydrogen production from sweet potato starch residue

Clostridium butyricum could produce hydrogen from a sweet potato starch residue upon supplementation of nitrogen sources. A repeated batch culture using a mixed culture of C. butyricum and Enterobacter aerogenes produced hydrogen with a yield of 2.4 mol H 2/mol glucose under a controlled culture pH of 5.25 in a medium consisting of the sweet potato starch residue and 0.1% Polypepton without addition of any reducing agents. Rhodobacter sp. M-19 produced hydrogen from the supernatant of the culture broth obtained in the repeated batch culture containing C. butyricum and E. aerogenes when 50 μg/ l Na 2MoO 4·2H 2O and 20 mg/ l EDTA were added to the supernatant and it was cultured under a controlled culture pH of 7.5. A high yield of hydrogen of 7.0 mol H 2/mol glucose from the starch remaining in the starch residue was attained in two-step repeated batch cultures containing C. butyricum and E. aerogenes, and by Rhodobacter sp. M-19.

Microbial Hydrogen Production from Sweet Potato Starch Residue.

Clostridium butyricum could produce hydrogen from a sweet potato starch residue upon supplementation of nitrogen sources. A repeated batch culture using a mixed culture of C. butyricum and Enterobacter aerogenes produced hydrogen with a yield of 2.4 mol H2/mol glucose under a controlled culture pH of 5.25 in a medium consisting of the sweet potato starch residue and 0.1% Polypepton without addition of any reducing agents. Rhodobacter sp. M-19 produced hydrogen from the supernatant of the culture broth obtained in the repeated batch culture containing C. butyricum and E. aerogenes when 50 microg/l Na2MoO4.2H2O and 20 mg/l EDTA were added to the supernatant and it was cultured under a controlled culture pH of 7.5. A high yield of hydrogen of 7.0 mol H2/mol glucose from the starch remaining in the starch residue was attained in two-step repeated batch cultures containing C. butyricum and E. aerogenes, and by Rhodobacter sp. M-19.

Feed intake, digestibility, plane of nutrition and live weight gain by crossbred growing bulls fed on grainless diets containing different nitrogen sources

Twenty five growing crossbred bulls ( Bos indicus× Bos taurus) were used in a randomised block design experiment for 196 days to determine the effect of grainless concentrate containing different supplemental nitrogen sources along with wheat straw based diet on feed intake, nutrient digestibility, plane of nutrition and daily live weight gain. The animals in control group received barley 30% in the concentrate mixture (Cm 1) as a source of grain, where as other concentrate mixtures contained only wheat bran (Cm 2) or wheat bran supplemented with 2.5% urea (Cm 3), 21.5% groundnut oil cake (Cm 4) or 27% mustard oil cake (Cm 5) as source of supplemental nitrogen. Fortnightly live weight gain was recorded and a metabolism trial of 6 days duration was conducted after 120 days of feeding trial in order to assess nutrient utilisation and retention as well as plane of nutrition. The mean dry matter (DM) intake and digestibility of the nutrients except crude protein (CP) were similar in all the groups. CP digestibility was significantly higher ( P<0.05) in urea fed animals. A positive nitrogen balance was recorded in all the groups. Though gross energy (GE) and digestible energy (DE) intake were not affected, the urinary loss of energy (UE) was significantly lower ( P<0.05) in animals fed Cm 2. A positive calcium and phosphorus balance was observed in all the treatments though phosphorus balance in Cm 2 fed animals was significantly higher ( P<0.05). Average daily live weight gains were 443, 344, 370, 435 and 423 g in Cm 1, Cm 2, Cm 3, Cm 4 and Cm 5 fed animals, respectively. A marginal less daily live weight gain was recorded in Cm 2 fed animals and the results were non-significant among the treatments. Active growth could be obtained in animals fed grainless concentrates having wheat bran as its main component at an amount of 1% of the live weight daily without showing significant influence on nutritional status and growth of growing bulls.

Biogasification of rice straw with an anaerobic-phased solids digester system

Rice straw was converted into biogas using a high-rate anaerobic digestion system, anaerobic-phased solids digester system (APS-digester system). The system was stable and, with proper design, could become a space-efficient, high-rate solids digestion system. Ammonia is used as a supplemental nitrogen source for rice straw digestion. The effects of different pretreatment methods, physical (mechanical), thermal and chemical (ammonia) treatment, on the digestion of rice straw were investigated at the mesophilic temperature of 35°C. A combination of grinding (10-mm length), heating (110°C), and ammonia treatment (2%) resulted in the highest biogas yield, 0.47 l g −1 VS −1 fed, which is 17.5% higher than the biogas yield of untreated whole straw. Pretreatment temperature has a significant effect on the digestibility of straw.