Inoculum Mixture Research Articles

Amendments promote Douglas-fir survival on Formosa Mine tailings.

While mining provides valuable metals and minerals to meet societal demands, it can cause environmental contamination from the residuals (i.e., tailings) of mining. Tailings are often acidic, laden with heavy metals, and lacking adequate nutrients and physical conditions for plant growth, precluding the establishment of plant cover to reduce the offsite movement of mining wastes. This paper describes a case study at the Formosa Mine in Douglas County, Oregon, where tailings were amended with a mixture of lime, biosolids, biochar, and microbial inoculum to facilitate establishment of Douglas-fir (Pseudotsuga menziesii [Mirbel] Franco) seedlings. Results show that the tailings pH increased, and Douglas-fir seedlings survived and grew with these amendments. After 2years, pH did, however, decrease in some downslope locations and was associated with an increase in tree mortality. This suggests that tailings conditions should be monitored, and amendments should be reapplied as needed, particularly in areas receiving acidic runoff from unamended upslope tailings, until the seedlings are fully established. This study not only provides a prescription for the addition of biochar and other amendments to enhance plant growth for revegetation purposes in low-pH, metal-contaminated mine tailings, but it also demonstrates a method that can be used to address similar problems at other mine sites.

Food Safety Aspects of Breeding Maize to Multi-Resistance against the Major (Fusarium graminearum, F. verticillioides, Aspergillus flavus) and Minor Toxigenic Fungi (Fusarium spp.) as Well as to Toxin Accumulation, Trends, and Solutions-A Review.

Maize is the crop which is most commonly exposed to toxigenic fungi that produce many toxins that are harmful to humans and animals alike. Preharvest grain yield loss, preharvest toxin contamination (at harvest), and storage loss are estimated to be between 220 and 265 million metric tons. In the past ten years, the preharvest mycotoxin damage was stable or increased mainly in aflatoxin and fumonisins. The presence of multiple toxins is characteristic. The few breeding programs concentrate on one of the three main toxigenic fungi. About 90% of the experiments except AFB1 rarely test toxin contamination. As disease resistance and resistance to toxin contamination often differ in regard to F. graminearum, F. verticillioides, and A. flavus and their toxins, it is not possible to make a food safety evaluation according to symptom severity alone. The inheritance of the resistance is polygenic, often mixed with epistatic and additive effects, but only a minor part of their phenotypic variation can be explained. All tests are made by a single inoculum (pure isolate or mixture). Genotype ranking differs between isolates and according to aggressiveness level; therefore, the reliability of such resistance data is often problematic. Silk channel inoculation often causes lower ear rot severity than we find in kernel resistance tests. These explain the slow progress and raise skepticism towards resistance breeding. On the other hand, during genetic research, several effective putative resistance genes were identified, and some overlapped with known QTLs. QTLs were identified as securing specific or general resistance to different toxicogenic species. Hybrids were identified with good disease and toxin resistance to the three toxigenic species. Resistance and toxin differences were often tenfold or higher, allowing for the introduction of the resistance and resistance to toxin accumulation tests in the variety testing and the evaluation of the food safety risks of the hybrids within 2-3 years. Beyond this, resistance breeding programs and genetic investigations (QTL-analyses, GWAM tests, etc.) can be improved. All other research may use it with success, where artificial inoculation is necessary. The multi-toxin data reveal more toxins than we can treat now. Their control is not solved. As limits for nonregulated toxins can be introduced, or the existing regulations can be made to be stricter, the research should start. We should mention that a higher resistance to F. verticillioides and A. flavus can be very useful to balance the detrimental effect of hotter and dryer seasons on aflatoxin and fumonisin contamination. This is a new aspect to secure food and feed safety under otherwise damaging climatic conditions. The more resistant hybrids are to the three main agents, the more likely we are to reduce the toxin losses mentioned by about 50% or higher.

Optimization of the cocoa shell, inoculum, and water mixture for biogas production with 40-70% methane concentrations

Biomass has been a valuable source of energy over the years and its application includes many areas, whether for cooking, heating, or electricity generation. In Honduras, especially in the rural sector, biomass, mainly firewood, became the main source of energy, which has led to a high consumption of firewood and, consequently, to an increase in the rate of deforestation. In this study, we proposed to use a more specific biomass, cocoa husk, as feedstock for biogas generation. It is important to note that biogas does not only consist of methane; it also contains carbon dioxide (CO2), nitrogen (N2), hydrogen sulfide (H2S) and oxygen (O2). However, to be considered of quality, the concentration of methane in the biogas must range between 40% and 70%. The main objective of this research has been to optimize the mixture of raw materials, including cocoa husk, water and inoculum, with the purpose of obtaining a methane (CH4) concentration in the biogas produced, located in the range of 40%-70%. To achieve biogas production, several tests were carried out in four biodigesters, each with different proportions of water, inoculum, cocoa husk and grinding level. This made it possible to obtain varying amounts of biogas and to measure the methane gas concentration in each test. During the operation of the biodigesters, the temperature and pH of the mixture were constantly monitored. This was possible because methanogenic bacteria, responsible for methane generation, thrive at temperatures between 30 and 40 degrees Celsius and in a pH range of 6 to 8. The results obtained have the potential to demonstrate that cocoa shells can be a viable feedstock for biogas generation in Honduras. Furthermore, these findings could serve as a basis for future research in other cities around the world, thus contributing to the search for energy generation solutions.

Cultivating Resilience in Dryland Soils: An Assisted Migration Approach to Biological Soil Crust Restoration.

Land use practices and climate change have driven substantial soil degradation across global drylands, impacting ecosystem functions and human livelihoods. Biological soil crusts, a common feature of dryland ecosystems, are under extensive exploration for their potential to restore the stability and fertility of degraded soils through the development of inoculants. However, stressful abiotic conditions often result in the failure of inoculation-based restoration in the field and may hinder the long-term success of biocrust restoration efforts. Taking an assisted migration approach, we cultivated biocrust inocula sourced from multiple hot-adapted sites (Mojave and Sonoran Deserts) in an outdoor facility at a cool desert site (Colorado Plateau). In addition to cultivating inoculum from each site, we created an inoculum mixture of biocrust from the Mojave Desert, Sonoran Desert, and Colorado Plateau. We then applied two habitat amelioration treatments to the cultivation site (growth substrate and shading) to enhance soil stability and water availability and reduce UV stress. Using marker gene sequencing, we found that the cultivated mixed inoculum comprised both local- and hot-adapted cyanobacteria at the end of cultivation but had similar cyanobacterial richness as each unmixed inoculum. All cultivated inocula had more cyanobacterial 16S rRNA gene copies and higher cyanobacterial richness when cultivated with a growth substrate and shade. Our work shows that it is possible to field cultivate biocrust inocula sourced from different deserts, but that community composition shifts toward that of the cultivation site unless habitat amelioration is employed. Future assessments of the function of a mixed inoculum in restoration and its resilience in the face of abiotic stressors are needed to determine the relative benefit of assisted migration compared to the challenges and risks of this approach.

Evaluation of Spraying Machine for Silage Production

Silage production requires a mixture of molasses, inoculum, and water to store forage. Inoculum or microbes is mixed into the forage to inhibit the reproduction of bacteria and organisms that could damage the silage. Silage processing requires workforces to manually prepare and measure liquid additives to formulate the solutions. In MARDI, a machine that accurately mixes an inoculum, water, and molasses has been developed. The machine eliminates the need for manual operation and can reduce the labor involved in preparing a liquid formulation. Besides, the machine enables agricultural input to be handled efficiently. This machine can increase silage production's productivity for ruminant feed preparation. The machine's accuracy is 99.63% for measuring water and inoculum, while 98.58% for measuring molasses solution. The machine's capacity is 30 barrels/hour for preparing a mixture of additive materials into 25 liters of water while 60 – 120 barrels/hour for preparing a mixture of additive materials into a 30kg silage barrel.

Bioaugmentation potential of inoculum derived from anaerobic digestion feedstock for enhanced methane production using water hyacinth

The utilisation of water hyacinth for production of biogas is considered to be a solution to both its control and the global renewable energy challenge. In this instance, an investigation was conducted to evaluate the potential of water hyacinth inoculum to enhance methane production during anaerobic digestion (AD). Chopped whole water hyacinth (10% (w/v)) was digested to prepare an inoculum consisting mainly of water hyacinth indigenous microbes. The inoculum was incorporated in the AD of freshly chopped whole water hyacinth to set up different ratios of water hyacinth inoculum and water hyacinth mixture with appropriate controls. The results of batch tests with water hyacinth inoculum showed a maximal cumulative volume of 211.67 ml of methane after 29 days of AD as opposed to 88.6 ml of methane generated from the control treatment without inoculum. In addition to improving methane production, inclusion of water hyacinth inoculum reduced the electrical conductivity (EC) values of the resultant digestate, and, amplification of nifH and phoD genes in the digestate accentuates it as a potential soil ameliorant. This study provides an insight into the potential of water hyacinth inoculum to enhance methane production and contribute to the feasibility of the digestate as a soil fertility enhancer.

The manifestation of diseases and phytophages of weeds associated with the cultivation of flax, the possibility of their use as biological plant protection agents

Materials on the study of diseases and phytophages of weeds associated with flax cultivation and on the results of their use in biological plant protection are presented. It has been established that the developed biopreparation (a mixture of inoculum of smut / urocystosis / couch-grass (the disease causative agent Urocystis agropyri / P./ S.) and rust /puccinia / yellow thistle (pathogen Puccinia suaveollens /Pers./) reduces the sowings contamination with these weeds. When sowing flax in regions new to this crop (for example, in the Tula region), phytophages unusual for this crop (for example, rapeseed flea) can significantly damage not flax, but cruciferous weeds. Studies have established that Cirsium setosum in flax sowings is often affected by a specific rust /puccinia / (pathogen Puccinia suaveollens /Pers./ R. [= P. obtegens /Lk./ Tul.]), causing on average about 20% of cases of its destruction without the formation of seeds.

Biodegradation of total petroleum hydrocarbons in oily sludge: a comparative study of biostimulation, bioaugmentation, and combination of methods

AbstractBACKGROUNDOne of the major parts of global environmental pollution is petroleum‐derived products. The purpose of this study was the biodegradation of total petroleum hydrocarbons (TPH) in oily sludge using biostimulation and bioaugmentation methods. The oily sludge was dredged from the bottoms of kerosene and oil gas storage tanks, and it was characterized according to American Society for Testing and Materials D1796 and the CHNS (equipment for determination Carbon, Hydrogen, Nitrogen and Sulfour) elements analysis. The TPH biodegradation potential of the indigenous bacteria in the oily sludge was investigated via biostimulation applying mineral salt medium(N). Besides it was compared with bioaugmentation with two oil degrader bacterium, namely Arthrobacter citreus (strain E) and Rhodococcus jostii (strain D), being separated from the oil‐contaminated soil. The gravimetric and GC (Gas Chromatography) methods were used for TPH removal assays.RESULTSThe results indicated that the biodegradation efficiency was dependent on treatment time and microbial species. Increasing pH and TPH biodegradation % for samples were observed over time. The highest removal degradations of hydrocarbons (75.1%) was reported using the inoculum mixture of strains D & E (pH = 7.02) at the 5th week.CONCLUSIONThis method could be used for bioremediation purposes at petroleum hydrocarbon‐contaminated sites as a biological technique. © 2020 Society of Chemical Industry

Application of ultrasonic disintegration to waste activated sludge for increasing of biogas production by anaerobic digestion

The municipal wastewater treatment is the source of significant amounts of primary and secondary sludge which is under the present legislation referring to quality and management aspects. It is estimated that a half of wastewater treatment plant costs are due to the sludge management. Anaerobically sludge stabilization, capitalization as energy source, in order to diminish the costs and sludge volume decreasing, are the aims of the main operational steps of sludge treatment, as a part of wastewater treatment plant. The improvement of sludge anaerobically stabilization process must be possible by acting in the rate limiting step - hydrolysis in order to rise the organic carbon solubilization. The increase of soluble carbon can be possible by adding a pretreatment step of waste biological sludge, ultrasonic disintegration being one option. This paper emphasized the experimental results regarding anaerobically stabilization of the thickened waste biological sludge by ultrasonication taking into account the results of blank test, without ultrasonication. Experimental tests show that ultrasonic disintegration of the sludge having initial dried substances content (d.w) 2.72% and soluble organic load COD of 598 mg O2/L led to soluble COD concentration of 4950-6710 mg O2/L after sonication with specific energy in the range of 3.06 - 14.24 kWh/kg d.w. Anaerobically stabilization during 25 test days at 36 0C of the mixture 40% disintegrated biological sludge and 60% digested sludge (inoculum) mixture led to 30-38.6% increase of biogas production comparing with parallel test with non-sonicated sludge.

Enhanced Methanization of Long-Chain Fatty Acid Wastewater at 20°C in the Novel Dynamic Sludge Chamber–Fixed Film Bioreactor

Lipid-containing wastewaters, such as those arising from dairy processing, are frequently discharged at temperatures ≤20°C. Their valorization at low ambient temperatures offers opportunities to expand the application of high-rate anaerobic wastewater treatment towards achieving energy neutrality by minimizing the energy demand for heating. Lipid hydrolysis generates long chain fatty acids (LCFA), which incur operational challenges and hinder stable bioreactor operation by inducing sludge flotation and washout, coupled with the added challenge of treatment at lower temperature (20°C). These challenges are tackled together uniquely during the treatment of LCFA-rich synthetic dairy wastewater (SDW) (33% COD-LCFA) through de-novo formed microbial granular sludge within the dynamic sludge chamber fixed film (DSC-FF) reactor. The novel reactor design facilitated sludge retention for the entire operational period of 150 days by containing settled, floating and LCFA-encapsulated granular sludge and biofilm within a single module. High COD removal efficiencies (87-98%) were achieved in the three replicated DSC-FF reactors, along with complete LCFA removal at 18-72 h HRT (LCFA loading rate of 220-890 mgCOD-LCFA/L·d) and partial LCFA removal at 12 h HRT (LCFA loading rate of 1333 mgCOD-LCFA/L·d). The high removal efficiencies of unsaturated and saturated LCFAs achieved are reported for the first time during continuous anaerobic wastewater treatment at low temperatures (20°C). Moreover, de novo granulation was achieved within 8 d from a combination of inoculum mixtures at a high LCFA concentration (33% COD-LCFA) in SDW. The results demonstrate the feasibility of the DSC-FF reactor for treating LCFA-rich wastewaters at discharge temperatures and offer potential for expanded and more energetically productive anaerobic valorization of lipid-rich wastewater.

Genomic recombination between infectious laryngotracheitis vaccine strains occurs under a broad range of infection conditions in vitro and in ovo.

Gallid alphaherpesvirus 1 causes infectious laryngotracheitis (ILT) in farmed poultry worldwide. Intertypic recombination between vaccine strains of this virus has generated novel and virulent isolates in field conditions. In this study, in vitro and in ovo systems were co-infected and superinfected under different conditions with two genomically distinct and commonly used ILTV vaccines. The progeny virus populations were examined for the frequency and pattern of recombination events using multi-locus high-resolution melting curve analysis of polymerase chain reaction products. A varied level of recombination (0 to 58.9%) was detected, depending on the infection system (in ovo or in vitro), viral load, the composition of the inoculum mixture, and the timing and order of infection. Full genome analysis of selected recombinants with different in vitro phenotypes identified alterations in coding and non-coding regions. The ability of ILTV vaccines to maintain their capacity to recombine under such varied conditions highlights the significance of recombination in the evolution of this virus and demonstrates the capacity of ILTV vaccines to play a role in the emergence of recombinant viruses.

Examination of mycorrhizal inoculum for improving maize tolerance to water stress in pot culture using zeolite and Andisol

Arbuscular mycorrhiza (AM) is known as beneficial microsymbiont that capable to support plant growth by increasing nutrient uptake and improving plant tolerance toward diverse adverse conditions, such as water stress. The present study examined single and mixture mycorrhizal inoculum sources for improving maize tolerance to water stress in pot culture using zeolite and Andisol. Pot culture experiment was conducted using a Factorial Completely Randomized Design with three factors: A: Media type (A0: zeolite, A1: Andisol), B: AM Inoculum sources (B0: No inoculum, B1: Inoculum from Andisol, B2: Inoculum from eight soil types), C: Media moisture level (C1: 50%, C2: 70% of field capacity), with three replications. Each pot contained 300 g of media that sterilized using formaldehyde 2%, Maize were grown until maximal vegetative phase (77 days after planting). The results showed that maize growth on Andisol was higher than on zeolite, inoculum from Andisol were resulted in higher effect than a mixture of inoculum from eight soil types. On zeolite media (A0), inoculum B1 showed to improve plant tolerance to water stress at moisture level of C1 as indicated by plant dry weight (PDW) that 38.6% higher than B2 and 31.9% higher than B0, whereas on Andisol (A1), inoculum B1 resulted PDW 13.4% higher than B2 and 38.4% higher than B0. By AM inoculation in pot culture, maize growth on zeolite media at C1 was lower than at C2, whereas maize growth on Andisol at C1 was higher than at C2 conditions.

Induced biological soil crust controls on wind erodibility and dust (PM10) emissions

ABSTRACTInducing biological soil crust (biocrust) development is an appealing approach for dust mitigation in drylands due to the resistance biocrusts can provide against erosion. Using a portable device, we evaluated dust emissions from surfaces either inoculated with biocrust, amended with a plant‐based soil stabilizer, or both at varying wind friction velocities. Four months after application, emissions from all treatments were either indistinguishable from or greater than controls, despite evidence of biocrust establishment. All treatments had greater surface roughness and showed more evidence of entrapment of windblown sediment than controls, factors which may have been partially responsible for elevated emissions. There was a synergistic effect of inoculation and stabilizer addition, resulting in a nearly two‐fold reduction in estimated emissions compared to either treatment alone. Stepwise regression analysis indicated that variables associated with surface crust strength (aggregate stability, penetration resistance) were negatively associated with emissions and variables associated with sediment supply (sand content, loose sediment cover) were positively associated with emissions. With more time to develop, the soil‐trapping activity and surface integrity of biocrust inoculum and soil stabilizer mixtures is expected to increase with the accumulation of surface biomass and enhancement of roughness through freeze–thaw cycles. © 2019 John Wiley & Sons, Ltd.

Inoculación de hongos micorrízicos arbusculares en el cultivo de Heliconia stricta

La inoculación con hongos micorrízicos arbusculares ha permitido un desarrollo y crecimiento controlado en especies hortícolas; sin embargo, no se ha evaluado su efecto en algunos cultivos ornamentales tropicales como las heliconias. El objetivo fue evaluar la aplicación de hongos micorrízicos arbusculares (HMA) en el desarrollo de Heliconia stricta, teniendo como hipótesis general que el uso de HMA incrementa la absorción de nutrientes como nitrógeno, fósforo, potasio y favorecer su aclimatación y crecimiento. Se evaluó el desarrollo fisiológico de las plantas de H. stricta como respuesta a su inoculación con cuatro HMA: Rhizophagus intraradices, Zac-19, mezcla de cepas e inóculo nativo en México. Se determinó la altura de las plantas, número de brotes, tasa fotosintética con un analizador de fotosíntesis IRGA, LI-COR 6400XT y colonización micorrízica por el método de Phillips y Hayman. Los resultados evidenciaron incrementos estadísticamente significativos por efecto del inóculo no nativo, en la altura de la planta, el número de brotes por planta, la tasa fotosintética y la colonización micorrízica (p≤ 0.05). El inóculo nativo produjo efectos estadísticamente significativos en la colonización de las raíces (p≤ 0.05). Se concluye que existe un efecto benéfico estadísticamente significativo (p≤ 0.05) de la inoculación micorrízica sobre el crecimiento de las plantas debido a su mayor altura, número de brotes por planta y tasa fotosintética.

Potential of Palm Oil Empty Fruit Bunch as Biogas Substrate

Natural gas is a source of energy that comes from the earth which is depleting every day, an alternative source of energy is needed and one of the sources comes from biogas. There is an abundance of empty fruit bunch (EFB) that comes from palm oil plantation that can become a substrate for biogas production. A methodology of fermentation based on Verein Deutscher Ingenieure was used to utilize EFB as a substrate to produce biogas using biogas sludge and wastewater sludge as inoculum in wet fermentation process under mesophilic condition. Another optimization was done by adding a different water ratio to the inoculum mixture. In 20 days, an average of 6gr from 150gr of total EFB used in each sample was consumed by the microbes. The best result from 20 days of experiment with both biogas sludge and wastewater sludge as inoculum were the one added with 150gr of water that produced 2910ml and 2185ml of gas respectively. The highest CH 4 produced achieved from biogas sludge and wastewater sludge with an addition of 150gr of water to the inoculum were 27% and 22% CH 4 respectively. This shows that biogas sludge is better in term of volume of gas that is produced and CH percentage.

First Report of Fusarium brasiliense Causing Root Rot of Dry Bean in the United States

Michigan is the second largest dry bean (Phaseolus vulgaris L.) producer in the United States and is ranked first in the production of black beans. Stand establishment and root rots are constant constraints in dry bean cultivation owing to susceptibility of germplasm. To determine which pathogens are responsible, surveys were conducted on Michigan State University research farms and in commercial dry bean fields in Michigan during 2014 to 2017. Fungi were isolated from symptomatic dry bean roots on water agar amended with metalaxyl (15 µg/ml) and streptomycin (300 µg/ml) at room temperature (22°C) under laboratory lighting conditions for 7 to 10 days. Single spore isolates were obtained from sporodochia, which developed on cultured root tissue. Fusarium isolates F-14-42, F-15-46, and F-15-174 were collected from Montcalm, Huron, and Gratiot Counties in Michigan, respectively. Colony morphology and color of isolates grown on full-strength potato dextrose agar at 25°C under dark conditions for 10 days displayed undulated margins, with variations in color of white, with tints of yellow, pink, or greyish-blue. On spezieller nahrstoffarmer agar or carnation leaf agar medium at 25°C under dark conditions for 10 days, sporodochia were a yellowish-white to pale yellow, and macroconidia were falcate, mostly four-septate, apex rounded or hooked ventrally, and base with a distinct foot cell (45.8 to 52.0 × 5.0 to 6.4 μm on average). DNA of each isolate was extracted using a cetyltrimethylammonium bromide method (Cubero et al. 1999), and the ribosomal intergenic spacer (IGS) region and partial translation elongation factor (EF-1α) were amplified by polymerase chain reaction with primer pairs NL11/CNS1 (Aoki et al. 2003) and EF1/EF2 (O’Donnell et al. 1998), respectively. A BLAST search of IGS and EF-1α sequences from the three isolates showed they were 100 and 99% identical with Fusarium brasiliense NRRL 22678 (GenBank accession nos. FJ919501 and AY320158). Phylogenetic analysis of IGS sequences of Fusarium solani species complex clade 2 revealed that the sequences of three isolates and two strains of F. brasiliense (NRRL 22678 and NRRL 31757) were clustered together in a group, which was supported by a bootstrap value of 97%. Based on morphological and sequence analysis, the isolates were identified as F. brasiliense (Aoki et al. 2005). All sequences obtained in this study were deposited into GenBank (accession nos. MG967556 to MG967561). To determine pathogenicity of isolates to dry bean, a seedling pathogenicity screening was performed on dark red kidney (cv. Red Hawk) and black (cv. Zorro) seed types. Each isolate was grown on Nash–Snyder medium at room temperature under laboratory lighting conditions for 21 days and inoculated to sterilized sorghum grain and incubated for 4 weeks to generate inoculum. Twelve grams of infested inoculum mixed with 250 ml of vermiculite was poured into a pot, with an additional 70 ml of vermiculite placed over the inoculum mixture. Six bean seeds were sown in each pot and covered with 70 ml of vermiculite. After 14 days, roots were harvested and washed for disease severity rating and measurement of dried root mass. Roots infected by F. brasiliense exhibited a large lesion of rot on the tap root, 20 to 50% reduction of root mass, and a disease severity rating of 4 on a 1 to 7 scale. The experiment was conducted twice with five replicate pots (six seeds in each pot) per experiment. The fungus was reisolated from the diseased roots and confirmed to be F. brasiliense. Soybean sudden death syndrome caused by F. brasiliense has been reported in Brazil and Argentina (Aoki et al. 2005; O’Donnell et al. 2010) and South Africa (Tewoldemedhin et al. 2017). Significantly, this is the first record of F. brasiliense causing root rot of dry bean in the United States.

Biogas from Fresh Spring and Summer Grass: Effect of the Harvesting Period

Yard trimmings, landscape management and agricultural practices determine the collection of biomass currently destined mainly to the production of a valuable soil amendant by composting. While composting requires energy, especially for the turning/aeration phases and for air treatment (i.e., biofilters in the case of enclosed systems), anaerobic digestion represents an energy positive process that results in production of biogas and digestate, which can be used as fuel and fertilizer, respectively. The focus of the present research was the evaluation of biogas and methane potential of grass collected in two different periods of the year (spring and summer) from riverbanks located in Northern Italy. The conversion to biogas of feedstocks is greatly influenced by the composition of the organic matter, content of cellulose, and lignin in particular. The production of biomass per hectare and the consequent biogas production were also evaluated. The experimental tests were performed on both samples of fresh grass in laboratory scale batch reactors, characterized by 4.0 L of volume and operated in mesophilic conditions (38 °C), for 40 days per cycle. The anaerobic digestion process was performed on a mixture of inoculum and grass, characterized by inoculum:substrate VS (volatile solids) ratio equal to 2. The inoculum was represented by digestate from a full-scale anaerobic digestion plant fed with dairy cow manure. The results in terms of biogas production, biogas quality (CH4, CO2, H2S), and emissions from digestates (NH3, CO2 and CH4) are presented in the paper. Total solids (TS), volatile solids (VS), pH, volatile fatty acids (VFA), alkalinity, acidity vs. alkalinity ratio, fibers (cellulose, lignin), and total Kjieldahl nitrogen (TKN) were determined both on input and output of the process. The biogas yield obtained from grass resulted higher than expected, quite similar to the yield obtained from energy crops, with Biomethane Potential (BMP) of 340.2 NL·kg−1VS and of 307.7 NL·kg−1VS, respectively, for spring and summer grass. Biogas quality was slightly lower for summer grass, perhaps in relation to the higher content of fibers (lignin). Alternatively, the yield of grass per surface was significantly different between spring and summer with the highest production in the summer. In fact, the results revealed a methane yield of 263 Nm3·ha−1 and of 1181 Nm3·ha−1, respectively for spring and summer grass.

Inoculum mixture optimization as strategy for to improve the anaerobic digestion of food waste for the methane production

Food waste (FW) represents the highest proportion of municipal solid waste (MSW), which due to its high biodegradability can be treated and recycled via anaerobic digestion (AD). Although in Latin America there is a high availability of flocculent sludges, they present deficiencies that limit their use as potential inoculum. In this study, the influence of incorporating a granular inoculum on the production of methane by the AD of FW, in combination with a flocculent inoculum from a sludge digester of a municipal wastewater treatment plant (inoculum A) was evaluated by biochemical methane potential (BMP) tests. The granular sludge was obtained from a methanogenic reactor that treats cattle slaughterhouse wastewater (inoculum B). The evaluated A:B mixtures (100:00, 75:25, 60:40, 50:50, 40:60, 25:75 and 00:100), showed that the incorporation of inoculum B (granular) improved the hydrolytic activity of the mixtures (values from 0.16–0.91 gCODGlucose) and provided adequate equilibrium between the specific acidogenic activity (SAA: 3.6–0.88 g CODGlucose gVS−1 d−1) and the specific methanogenic activity (SMA: 0.047–0.19 gCODCH4 gVS−1 d−1). The 75:25 and 50:50 inoculum mixtures produced superior BMP and physicochemical characteristics and microbiological activities. The expected Kh behavior was not observed due to the extended lag-phase that occurred in the experiment (8–12 days) and the presence of particulate organic matter, which is common for this type of substrate. With respect to the stability determination factor (If), the inoculum mixtures with higher proportions of granular sludge demonstrated greater stability during the AD process.

Influence of Organic Loading Rates (OLR) in Treatment of Pulp and Paper Mill Wastewater with Hybrid Upflow Anaerobic Sludge Blanket Reactor (HUASBR) with Hexagonal Polypropylene Inert Material

Abstract The present work illustrates the effective treatment of raw pulp and paper mill effluent using a model hybrid upflow anaerobic sludge blanket reactor (HUASBR). The physico-chemical and biological characteristics of wastewater were observed to be critical from the pollution potential aspect. The design features of model HUASBR had a respective total and effective working capacity of 7.5 and 6.5l, together with 25 cm depth of packing by polypropylene hexagonal inert material at the top of the reactor. Start-up of the reactor was carried out using an inoculum mixture containing rumen liquid of goat and cow dung slurry at an appropriate ratio of 3 : 1(v/v). Also, the reactor was effectively started up at the end of 36 days. Based on the performance of model HUASBR, under the respective variations of organic loading rates (OLRs) of 1, 2 and 4 kg COD m−3 d−1, the stepwise COD removals were found to be about 41, 69 and 87%. However, a hydraulic loading rate (HRT) of 20 h was appropriately maintained throughout the studies.

Arbuscular Mycorrhizal Fungal Composition Affects the Growth and Nutrient Acquisition of Two Plants from a Karst Area

How the composition of the arbuscular mycorrhizal (AM) fungal community affects plant traits of different plant species in karst environments is poorly understood. Broussonetia papyrifera (a woody shrub) and Bidens pilosa (a herbaceous plant) growing in pots in limestone soil were inoculated with an AM fungus, either Funneliformis mosseae (FM), Diversispora versiformis (DV) or Glomus diaphanum (GD) or with an inoculum mixture of all three AM fungi (bn). B. papyrifera and B. pilosa seedlings inoculated with AM fungi showed a significant increase in biomass and nitrogen and phosphorus acquisition compared with the controls, which lacked mycorrhiza. Mixed fungal inoculations significantly enhanced biomass and nitrogen and phosphorus acquisition by B. papyrifera seedlings compared with single fungal inoculations. Nitrogen and phosphorus acquisition by B. papyrifera mycorrhizal seedlings was significantly greater than that of B. pilosa mycorrhizal seedlings. Fungal composition significantly influenced the mycorrhizal benefits of biomass and phosphorus acquisition and mixed fungal inoculations enhanced nitrogen acquisition. Plant species significantly affected nitrogen acquisition but did not have an effect on biomass and phosphorus benefits. We concluded that AM fungal associations increased plant growth and nutrient absorption and that in general a mixed inoculation of AM fungi enhanced biomass and nutrient acquisition more than a single AM fungal inoculation. In addition, a mycorrhizal association was more beneficial for B. papyrifera seedlings in terms of biomass and nutrient acquisition than for B. pilosa seedlings.