Chemostimuli implicated in selection of oviposition substrates by the stable fly Stomoxys calcitrans

Horse and cow dung were tested as substrates for oviposition by the stable fly Stomoxys calcitrans (L) (Diptera: Muscidae) in laboratory cages. Odour alone from either horse or cow dung was sufficient to attract flies for oviposition. This was confirmed in wind tunnel experiments, where both horse and cow dung were shown to attract gravid stable flies. However, when S. calcitrans was offered a choice between these two oviposition substrates, flies always chose horse dung over cow dung, both when allowed to contact the substrates and when relying on dung odour alone. Analyses of volatile compounds emanating from horse and cow dung by gas chromatography linked antennogram recordings from S. calcitrans antennae revealed no differences in the chemostimuli released from the two substrates. The predominant chemostimulant compounds in both substrates were carboxylic acids (butanoic acid), alcohols (oct-1-en-3-ol), aldehydes (decanal), ketones (octan-3-one), phenols (p-cresol), indoles (skatole), terpenes (beta-caryophyllene) and sulphides (dimethyl trisulphide). Higher levels (20-40 p.p.m.) of carbon dioxide were recorded over horse dung compared with cow dung, a factor that may contribute to the preference exhibited by S. calcitrans for this substrate for oviposition.     

内蒙古典型草原马粪分解过程中氮素组分的变化

2008年6月至2009年9月,在野外条件下,采用堆置于地表和埋入地下2种处理方式,研究了内蒙古典型草原马粪分解过程中氮素组分的变化特征.结果表明： 2种处理残留马粪中,氨态氮、氨基酸态氮和氨基糖态氮在分解前期(0~90 d)维持较高浓度,后期(330~450 d)浓度显著降低;酸解未知氮和非酸解未知氮浓度随分解呈升高趋势,分解后期升高幅度更为明显.鲜马粪中,铵态氮是无机氮的主要存在形态,随分解呈逐渐降低趋势;鲜马粪中的硝态氮浓度较低,其在残留马粪中的淋溶损失较低,随分解逐渐累积.马粪埋入地下,对铵态氮以气态氨的挥发过程有显著影响,对其他氮素组分的影响不明显.马粪分解前期,氮素矿化的主要有机氮源为氨态氮、氨基酸态氮和氨基糖态氮,后期主要为酸解未知氮和非酸解未知氮.铵态氮的生物有效性主要体现在马粪分解前期,硝态氮则体现在分解后期.     

Impact of process parameters on chitinase production by an alkalophilic marine Beauveria bassiana in solid state fermentation

A chitinolytic fungus, Beauveria bassiana was isolated from marine sediment and significant process parameters influencing chitinase production in solid state fermentation using wheat bran were optimised. The organism was strongly alkalophilic and produced maximum chitinase at pH 9·20. The NaCl and colloidal chitin requirements varied with the type of moistening medium used. Vegetative (mycelial) inoculum was more suitable than conidial inoculum for obtaining maximal enzyme yield. The addition of phosphate and yeast extract resulted in enhancement of chitinase yield. After optimisation, the maximum enzyme yield was 246·6 units g⁻¹ initial dry substrate (U gIDS⁻¹). This is the first report of the production of chitinase from a marine fungus.     

Enhanced lignin peroxidase synthesis by Phanerochaete Chrysosporium in solid state bioprocessing of a lignocellulosic substrate

Summary A solid state fermentation (SSF) process for the production of lignin peroxidase was optimized to enhance enzyme production by Phanerochaete chrysosporium. Optimization of the corncob SSF medium caused a significant reduction in fermentation time to give maximum lignin peroxidase yield. Supplementation of the SSF medium by low concentrations of peptone, yeast extract and Tween-80 enhanced lignin peroxidase production. Maximum yield of lignin peroxidase was 13.7 U/gds (units per gram dry substrate) noted after 5 days of SSF with 70% moisture and 20% (v/w) inoculum.     

Bioenergetics of an ecotechnical system of laying hen farms

Solar energy, fodder energy, microclimate optimization energy as well as technological process energy were defined as energy flows entering an egg production ecotechnical system. Nutrition biomass, chemical bond energy (eggs) and dung energy were estimated. Two criteria for energy consumption assessment were introduced: energy (kJ) consumed per unit of product and energy (kJ) consumed per unit of energy. Five fowl breeds were investigated. Restructuring in poultry farming was viewed with respect to the introduction of high performance breeds with low values of energy consumption. Elimination of systematic stress (abrupt transition of light intensity) reduced energy consumption in egg production. Methane fermentation parameters were optimized experimentally under laboratory conditions using a mathematical model. Dung biogas introduced an average of 25.75–29.52 MJ per bird into the observed system.     

Co-composting of physic nut (Jatropha curcas) deoiled cake with rice straw and different animal dung

To address the dispensing of this growing volume, a study on utilization of jatropha (Jatropha curcas) deoiled cake through compost production was carried out. The deoiled cake was composted with rice straw, four different animal dung (cow dung, buffalo dung, horse dung and goat dung) and hen droppings in different proportions followed by assessment, and comparison of biochemical characteristics among finished composts. Nutrient content in finished compost was within the desired level whereas metals such as copper, lead and nickel were much below the maximum allowable concentrations. Although a few finished material contained phorbol ester (0.12 mg/g), but it was far below the original level found in the deoiled cake. Such a study indicates that a huge volume of jatropha deoiled cake can be eliminated through composting.     

The effect of seeds of exotic species transported via horse dung on vegetation along trail corridors

It has been suggested that exotic species will colonize within forests more frequently by the continual introduction of seeds through horse dung deposited along trails. Whether or not these exotic species have the ability to spread into and establish in the forest interior has been disputed. To address this, horse dung and soil samples were collected from trails during Autumn 1994 and Summer 1995 from three areas in southern Illinois, USA open to recreational horse travel. In addition, deer dung samples were collected from each of the study areas. Vegetation data were collected from each of the trail systems as well as from a trail along which horse travel was prohibited. The density of vascular plants in 0.25 m² quadrats placed at varying distances from the trail center to 5 m into the forest interior were recorded. Finally, dung samples were placed in situ along horse trails at one site to examine seedling germination in natural conditions. While 23 exotic species germinated from samples of horse dung placed out in a greenhouse, only one of these exotic species was also found in trail plots (Kummerowia striata). Similarly, while there were empirically more exotic species found along the trails allowing horse travel than there were on the trail lacking horse travel, the relative importance of those species was negligible along both trails. These results suggest that the emigration of exotic species via horse dung does not pose an immediate threat to the plant communities adjacent to trails in these forest systems. Nevertheless, the large number of exotic species in horse dung reflects the constant threat to any system from these species. Care must be taken, when allowing horseback use in areas, to anticipate invasion by exotic species from horse dung     

Evaluation of an Inoculum Production and Delivery Technique for Valdensinia heterodoxa, a Potential Biological Control Agent for Salal

Inoculum production of Valdensinia heterodoxa Peyr. (isolate PFC 3027), a foliar pathogen of salal (Gaultheria shallon Pursh.), was evaluated on various solid substrates. Incubation on salal leaf pieces resulted in the greatest number of discharged conidia, which is deemed a suitable indicator for sporulation and inoculum dispersal of V. heterodoxa. Subsequently, V. heterodoxa inoculum of two isolates (PFC 2761 and PFC 3027) was produced on salal leaf pieces using four different growth periods (0, 4, 8, or 12 days) and three different cold storage treatments (0, 4, or 8 weeks) following harvest of colonised leaf pieces. Overall, the maximum number of discharged conidia was obtained with a growth period of 4 or 8 days, whereas the effect of a cold storage treatment was inconclusive between the fungal isolates and various growth periods. Conidia discharge from salal leaf piece inoculum of V. heterodoxa (PFC 2761 and PFC 3027) applied on pot soil level resulted in 8-41% leaf damage of intact salal plants. Results from this study indicate the potential of salal plant tissue as both a growth substrate and a suitable delivery technique for V. heterodoxa to control salal.     

A global review of weeds that can germinate from horse dung

To assess the diversity of weed seeds dispersed via horse dung, we reviewed 15 studies on seed germination from horse dung – six from Europe, four from North America, three from Australia and one study each from Africa and Central America. Seed from 249 species from 43 families have been identified germinating from horse dung. Almost two‐thirds of the species were forbs and 33% graminoids, with over half being perennials and 32% annuals. Nearly every species (totalling 99% of those reviewed) is considered a weed somewhere, with 47% recorded as invasive and 19% international environmental weeds. Of the 2739 non‐native plants that are naturalized in Australia, 156 have been shown to germinate from horse dung. This includes 16 of the 429 listed noxious weeds in Australia and two weeds of national significance. Seed from 105 of the 1596 invasive/noxious plant species in North America have also been identified germinating from horse dung. Seed traits including seed size, length, width and mass affect dispersal via horse dung. Habitat disturbance from trampling facilitates germination of seedlings from dung in both natural and experimental studies. Some studies found that plants germinating from dung reach maturity and flower, while others found plants did not survive due to unfavourable growing conditions in the field. The diversity of species with seed that can germinate from horse dung highlights the potential of horses to disperse a range of seed over long distances. Whether such dispersal is beneficial or harmful depends on the plant and the context in which it germinates. To maintain the conservation value of protected areas, it is important to understand and manage the different potential weed dispersal vectors, including horses.     

Effects of rumen fluid collection site on microbial population structure during in vitro fermentation of the different substrates quantified by 16S rRNA hybridisation

Rumen fluid samples from a cow were withdrawn manually from the feed mat (solid phase) or the liquid phase below this mat and incubated in vitro with wheat straw, sorghum hay and a concentrate mixture. From the inoculum and several samples collected during in vitro incubation RNA was extracted to assess microbial population size and structure. RNA content recovered from the solid phase rumen fluid was significantly higher than from the liquid phase. The composition of the microbial population in the solid phase material was characterised by a high proportion of Ruminococci. Neither the proportion of other cell wall degrading organisms (Fibrobacter and Chytridiomycetes) nor the Eukarya and Archaea populations differed between the two sampling sites. Gas production was higher when substrates were incubated with solid phase than with liquid phase rumen fluid regardless of sampling time. However, the higher level of gas production was not accompanied by a corresponding increase in true digestibility. The RNA probes showed that during in vitro incubation with liquid phase rumen fluid, the eukaryotic population was inactive no matter which substrate was used and the activity of methanogens (Archaea) was lower than with solid phase rumen fluid. The population pattern of the cell wall degrading organisms was influenced mainly by the substrate fermented, and to a smaller extent by the inoculum used for in vitro fermentation.     

Microbial Transformation of 2,4,6-Trinitrotoluene in Aerobic Soil Columns

2,4,6-Trinitrotoluene (TNT)-contaminated soil material of a former TNT production plant was percolated aerobically in soil columns. Nineteen days of percolation with a potassium phosphate buffer supplemented with glucose or glucose plus ammonium sulfate caused an over 90% decline in the amount of extractable nitroaromatics in soils containing 70 to 2,100 mg of TNT per kg (dry weight). In the percolation solution, a complete elimination of TNT was achieved. Mutagenicity and soil toxicity were significantly reduced by the percolation process. 4-N-Acetylamino-2-amino-6-nitrotoluene was generated in soil and percolation fluid as a labile TNT metabolite.     

Microbial production of citric acid in fixed-bed column bioreactors

Summary Aspergillus niger NRRL 567 was cultured on the solid substrate, fruit pomace, in fixed-bed column bioreactors to produce citric acid. The rates of substrate consumption and citric acid production were strongly influenced by (1) the rate of aeration, (2) the fermentation temperature, (3) the initial moisture content of the substrate, and (4) the size of the inoculum. This culture method yielded approximately 130 g of citric acid per kg of apple pomace fermented under optimum conditions.     

Solid state fermentation of rice chaff for fibrinolytic enzyme production by Fusarium oxysporum

Rice chaff was used as the substrate for the production of fibrinolytic enzyme by Fusarium oxysporum in solid state fermentation. The optimized moisture content of the medium was 30 - 50% (v/w). An inoculum of 5 - 10% (v/v) and an average particle size of 400 μm for the substrate were optimum for productivity and enzyme activity of 80 IU per ml filtrate was achieved after 96 hours of fermentation. This revised version was published online in November 2006 with corrections to the Cover Date.     

Methane Production from Cattle Waste and Delignified Straw

Methane production from added substrate per se was approximately twofold greater from delignified straw than that from untreated straw when fermented with cattle manure.     

Exoglucanase production by Aspergillus niger grown on wheat bran

β-Exoglucanase production on the lignocellulosic material, wheat bran, by Aspergillus niger under solid state fermentation (SSF) on a laboratory scale was investigated. Different fermentation parameters, such as moisture content, initial pH, temperature, depth of the substrate, and inoculum size on exoglucanase production were optimized. Moisture content of 40 %, pH of 7.0, substrate depth of 1.0 cm, inoculum size of 2?×?10⁶ spores/g of wheat bran, and temperature at 30 °C were optimal for maximum production of exoglucanase. Maximum yields of exoglucanase with 28.60 FPU/g of wheat bran were obtained within 3 days of incubation under optimal conditions.     

Corn husk as a novel substrate for the production of rifamycin B by isolated Amycolatopsis sp. RSP 3 under SSF

Rifamycin B production by isolated Amycolatopsis sp. RSP 3 was investigated under solid state fermentation (SSF) using agro-industrial waste materials. Corn husk was the most suitable substrate/support material with 4-fold higher production than wheat bran and corn cobs. A two-level (conventional and statistical) methodology was used to optimize fermentation parameters belong to physiological (pH, temperature and aeration), nutritional (carbon and nitrogen sources) and microbial (inoculum level and incubation time). Conventional optimization significantly improved (450%) the rifamycin B production of which two-third was associated with carbon and nitrogen sources. Starch as carbon source showed negative impact. Statistical optimization of suggested potassium nitrate (at individual level), soya bean meal and barbital (at interactive level) were observed to be the most noticeable variables in the maximization of production. At optimized conditions, inorganic nitrogen source played vital role (>59%) compared to all other factors. Overall, more than 920% increase in rifamycin B production was achieved at optimized environment.     

Review of solid state fermentation for lignocellulolytic enzyme production: challenges for environmental applications

Within the context of increasing environmental concern, energy production from lignocellulosic substrates is gaining great interest. Enzymes have proven their efficiency in the degradation of the lignocellulosic complex but their use remains limited in environmental applications such as anaerobic digestion mainly due to their prohibitive cost. Therefore, solid state fermentation (SSF) emerges as an interesting alternative for the in situ production of lignocellulolytic enzymes. Various research efforts on the lab scale optimization of SSF are discussed. They are presented according to the type of inoculum used in the process: bacterial species and fungal species under both mesophilic and thermophilic conditions. In general, parameters that impact the SSF process include: substrate type and particle size, substrate pretreatment, inoculum, nutrient supplementation, moisture content, pH, aeration, temperature and mixing. Using different substrates, authors aim at maximizing enzyme production taking into account one to several of the indicated operational parameters. The reviewed research puts forward the adaptation of the operational parameters, enzyme production cost and loading, enzyme mixture quality and efficiency and finally reactor design as the main challenges for environmental large-scale application.     

Attraction of Liomys mice to horse dung and the extinction of this response

When horse dung containing the large seeds of Enterolobium cyclocarpum (the guanacaste tree) was experimentally placed in a tropical deciduous forest in Costa Rica (Santa Rosa National Park), Liomys salvini (Heteromyidae) spiny pocket mice went to it and dug out the seeds. When the Liomys in a particular area were repeatedly offered dung containing E. cyclocarpum seeds, they developed an attraction response to the dung that was so strong that seed-free fresh horse dung made better bait in traps than did an oatmeal-peanut butter mix. A single exposure to seed-rich dung was not adequate to generate this response, but two exposures generated a mild response. Once moderately seed-rich dung was no longer forthcoming, the mice in an area lost their strong attraction to horse dung in 3 to 4 months; this loss was due at least in part to the mice learning that the dung no longer contained seeds, since the same individual mice that earlier had been attracted to horse dung were still present as demonstrated by capturing them with other baits.     

Enrichment of bitumen-degrading microorganisms

Enrichment cultures in a percolation apparatus with two different soil types supplemented with bitumen, were used to follow growth on this complex substrate. Microscopic techniques allowed visualisation of bacteria on solid surfaces of bitumen and soil particles; quantification was only possible in the percolation fluid. In the latter, changes in pH and amount of organic material provided evidence for metabolic activities and degradation of the substrate bitumen.     

Response surface optimization of mixed substrate solid state fermentation for the production of lovastatin by Monascus purpureus

The objective of this work is to enhance the production of lovastatin using Monascus purpureus MTCC 369 in mixed substrate solid state fermentation using various solid substrates and to optimize the combination of the solid substrates by response surface methodology. Solid state fermentation was conducted in a 250 mL Erlenmeyer flask at 30°C for 14 days with initial moisture content of 40% and inoculum size of 10% active culture. Barley, long grain rice and sago starch were found to be the suitable substrates producing maximum lovastatin of 193.7 mg, 190.2 mg and 180.9 mg/g of dry solids. These substrates were further used in various combinations as designed by the central composite design for enhancing the lovastatin production using Monascus purpureus. To the best of our knowledge this is the first report on the production of lovastatin using a mixed substrate solid state fermentation using Monascus purpureus.