Addition Of Inoculum Research Articles

Chemical characteristics of beddings for swine: Effects of bedding depths and of addition of inoculums in a pilot-scale

The effect of depths and of addition of inoculums on the chemical content of swine beddings was evaluated. For beddings 0.25m (25D) and 0.50m (50D) deep, three treatments were tested in two repeats with the same beddings: control (no inoculums); T1 (250g of Bacillus cereus var. toyoii at 8.4×107CFU/g); and T2 (250g of a pool of Bacillus sp. at 8.4×107CFU/g) (250g for 25D and 500g for 50D). For 25D, the C:N ratio was lower, but N, K and C contents were greater than for 50D (P<0.05). The inoculums did not benefit any chemical parameter (P>0.05). In the second repeat, beddings presented lower C:N ratio and greater N, P and K contents than in the first repeat (P<0.05). Thus, the compost produced after using 25D twice had greater fertilizer value than that of 50D.

Effects of Resident Soil Fungi and Land Use History Outweigh Those of Commercial Mycorrhizal Inocula: Testing a Restoration Strategy in Unsterilized Soil

Arbuscular mycorrhizal fungi (AMF) have numerous effects on temperate grassland ecosystems, but prairie restorations are frequently located in sites with depauperate AMF communities. In this greenhouse study, four native species (Schizachyrium scoparium, Elymus canadensis, Monarda punctata, and Aster ericoides) and an invasive grass (Bromus inermis) were grown in unsterilized field soils and treated with two types of commercial AMF inoculum. Inocula were applied at one and two times the manufacturers' suggested rate. Soil was collected from a meadow enrolled in the Conservation Reserve Program (CRP), and from an active agricultural field. Inoculum addition had no effect on biomass or percent colonization by AMF for any grass species, regardless of soil type. Inoculum type significantly affected Aster biomass and percent colonization, although pairwise comparisons of treated individuals and controls were not significant. The overall lack of effectiveness of the commercial inocula may reflect the small number of propagules added, even when used at twice the recommended rate. Higher rates of fungal colonization in all three grasses and increased biomass in the native grasses were observed in individuals grown in the CRP soil. Plants were also colonized by dark septate endophytic fungi; for Schizachyrium, endophyte colonization was significantly greater in tilled than CRP soil. Our results indicate that an existing soil fungal community promotes colonization by AMF more than the addition of commercial inocula, and that soil characteristics associated with land use history significantly affect the growth of native species in a restoration setting.

Addition of Bacillus sp. inoculums in bedding for swine on a pilot scale: Effect on microbial population and bedding temperature

Thermal and microbiological characteristics of beddings for swine were compared according to their depth and of addition of inoculums. Bedding was added to boxes at 0.25 (25D) and 0.50m (50D), with three treatments: control (no inoculums); T1, with 250g of Bacillus cereus var. toyoii at 8.4×107 CFU; and T2, with 250g of a pool of B. subtilis, Bacillus licheniformis and Bacillus polymyxa at 8.4×107 CFU (250g for 25D and 500g for 50D). Mean temperatures were 28.5±3.9 at the surface and 35.2±8.9 inside the beddings. The most probable number (MPN) of thermophilic bacteria was higher for T1 and T2 than for the control (P<0.05). The MPN of thermophilic bacteria and fungi was greater for D50 than for D25 (P<0.05). The use of 25D without inoculums is recommended due to the reduction of thermophilic microbiota.

Bioaugmented composting of Jatropha de‐oiled cake and vegetable waste under aerobic and partial anaerobic conditions

This study was conducted to assess the effect of microbial inoculation in Jatropha cake composting with different vegetable waste. The microbial inoculums composed of fungal strains (Aspergillus awamori, Aspergillus nidulans, Trichoderma viride, Phanerochaete chrysosporium) and bacterial inoculums (Pseudomonas striata as phosphorus solublizer and Azotobacter chroococcum as nitrogen fixer) were added to the compost mixture after the thermophilic phase was over for bioaugmenting of Jatropha cake under aerobic and partial anaerobic conditions. Addition of both fungal and bacterial inoculum with mixed substrate (Jatropha cake + vegetable waste) during composting (aerobic and partial anaerobic) showed, better results as compared to compost with only fungal inoculants. Increased enzymatic activity initially, during composting (like dehydrogenase, alkaline phosphatase activity and FDA) proved role of inoculated microbes in rapid decomposition. Analysis of compost (with both bacterial and fungal inoculum) showed presence of high humus (12.7%), humic acid (0.5%), fulvic acid (5.68%), soluble protein content and low C/N ratio. Decreased in concentration of extractable metals (Cu, Fe and Mn) were recorded at maturity in all the substrate composts. The C/N ratio was significantly correlated to parameters like humic acid, humus, fulvic acid, protein and also microbial activity parameters. We conclude that the composting of de-oiled Jatropha cake with different vegetables waste could be feasible and sustainable approach in recycling of agricultural and industrial residues in huge quantities.

Optimizing biohydrogen production from mushroom cultivation waste using anaerobic mixed cultures

The mushroom bag is a polypropylene bag stuffed with wood flour and bacterial nutrients. After being used for growing mushroom for one to two weeks this bag becomes mushroom cultivation waste (MCW). About 150 million bags (80,000 tons) of MCW are produced annually in Taiwan and are usually burned or discarded. The cellulosic materials and nutrients in MCW could be used as the feedstock and nutrients for anaerobic biohydrogen fermentation. This study aims to select the inoculum from various waste sludges (sewage sludge I, sewage sludge II, cow dung and pig slurry) with or without adding any extra nutrients. A batch test was operated at a MCW concentration of 20 g COD/L, temperature 55 °C and an initial cultivation pH of 8. The results show that extra nutrient addition inhibited hydrogen production rate (HPR) and hydrogen production yield (HY) when using cow dung and pig slurry seeds. However, nutrient addition enhanced the HPR and HY in case of using sewage sludge inoculum and without inoculum. This related to the inhibition caused by high nutrient concentration (such as nitrogen) in cow dung and pig slurry. Peak HY of 0.73 mmol H2/g TVS was obtained with no inoculum and nutrient addition. However, peak HPR and specific hydrogen production rate (SHPR) of 10.11 mmol H2/L/d and 2.02 mmol H2/g VSS/d, respectively, were obtained by using cow dung inoculum without any extra nutrient addition.

Hydrolysis and acidification of grass silage in leaching bed reactors

Hydrolysis and acidification of grass silage (GS) was examined in leaching bed reactors (LBRs) under organic loading rates (OLRs) of 0.5, 0.8 and 1.0kg volatile solids (VS)/m3/day. The LBRs were run in duplicate over five consecutive batch tests (Batch tests 1–5) to examine the effects of pH, leachate dilution and addition of inoculum on the process of hydrolysis and acidification. The highest GS hydrolysis yields of 52–58%, acidification yields of 57–60% and VS removals of 62–66% were obtained in Batch test 4. Increasing OLRs affected the hydrolysis yield negatively. In Batch test 4, the reduction of lignocellulosic materials was up to 74.4% of hemicellulose, 30.1% of cellulose and 9.3% of lignin within 32days. Cellulase activity can be used as an indicator for the hydrolysis process. Methane production from the LBRs only accounted for 10.0–13.8% of the biological methane potential of GS.

The role of nutrients in the biodegradation of 2,4,6-trinitrotoluene in liquid and soil

The widely used explosive 2,4,6-trinitrotoluene (TNT) has residues that are potentially explosive, toxic, and mutagenic. TNT and other explosives can be degraded by microorganisms; however, biostimulation is needed for process efficiency. To investigate the effectiveness of using biostimulation to degrade TNT, we added varying concentrations of a nutrient amendment consisting of inorganic salts, plant extracts, and molasses to soil and liquid media. For the inoculum we used a consortium of bacteria AM 06 that had exhibited the ability to degrade TNT and which had been previously isolated from explosives-contaminated soils. Phylogenetically, the clones clustered into seven different genera: Klebsiella, Raoultella, Serratia, Stenotrophomonas, Pseudoxanthomonas, Achromobacter and Pseudomonas. The addition of AM 06 consortium to a liquid environment along with 100% nutrient amendment decreased the amount of TNT (and its degradation products) by up to 90% after 14 days incubation. At the total amount of TNT was less than 100 mg/l, the concentration of TNT did not influence the amount of sugar consumed by the bacteria consortium. In soil media, the TNT degradation process was dependent on the concentration of nutrient amendment added. At higher initial concentrations of TNT (500 mg/kg), bioaugmentation (i.e., addition of bacteria inoculum) had a demonstrated effect, especially when nutrient concentrations of 50% and 100% were added to the soil. Findings of this study could further the understanding of the TNT biodegradation processes in water and soil and provide for optimization of the technological conditions for bioremediation.

Relationship between Incidence of Cephalosporium Stripe and Yield Loss in Winter Wheat

Cephalosporium stripe (caused byCephalosporium gramineum) can be a serious disease of winter wheat (Triticum aestivumL.) in the Pacific Northwest of the USA. Effects of Cephalosporium stripe on yield, test weight, protein, and kernel characteristics were examined using 12 winter wheat varieties in field plots inoculated and not inoculated with the pathogen. Averaged over varieties, inoculation decreased yield, test weight, kernel weight, and kernel diameter; grain protein and the standard deviations of kernel weight and kernel diameter were increased by inoculation. Grain yield of the susceptible check was reduced by as much as 41% with addition of inoculum. The most resistant and the most susceptible varieties performed similarly for yield in the two environments, while varieties with intermediate levels of resistance were sometimes inconsistent. There was a linear relationship between yield and % whiteheads (sterile heads caused by disease) in one environment and a curvilinear relation in the other.

Anthracene Removal using Activated Soil Reactors

The aim of this study was to evaluate anthracene removal using activated soil reactors, previously inoculated, under both aerobic and anaerobic conditions. In the reactors, the soil was maintained at 60% moisture (weight basis), room temperature, in the dark, and under constant agitation at 100 rpm. Two experiments were run during and after acclimatization to evaluate anthracene removal under both aerobic and anaerobic conditions. The first one took place during inoculum acclimatization using three different concentrations of anthracene (50, 100, and 500 mg anthracene/L per day) during 90 days. The second experiment took place after acclimatization (during 132 days). The results of anthracene removal were compared with controls in which no additional inoculum was added. During the two experiments, the behavior of pH, chemical oxygen demand (COD), and biogas production was evaluated. Results indicate that the bacterial community adapted for removal of anthracene became enriched through the acclimatization process. Anthracene biodegradation occurred in the soil model with both types of reactors (aerobic and anaerobic), but the rates and extent of biodegradation in the aerobic reactor were higher (95%) than those in anaerobic conditions (74%). Microbial activity also contributed to enhancing bioremediation in the soil by reducing anthracene sorption.

Manejo racional de resíduos da cultura do fumo (Nicotiana tabacum L.) para obtenção de composto orgânico

Crop residues may be used to produce organic composts for agricultural use. The aim of this study was to evaluate the effect of two inoculums on the decomposition speed of tobacco residues (stems). The experiment was carried out in a completely randomized design, with three treatments and six replications. The residue used in the study was passed through a forage chopper and mixed to the inoculums in a concrete truck mixer. The treatments evaluated were: TF + EB + RB - tobacco residue, bovine manure and bovine rumen; TF + EB + MP - tobacco residue, bovine manure and Microsept-Dust and TF + EB - tobacco residue and bovine manure. The temperature and humidity of the piles were monitored weekly. The piles were initially turned up side down every seven days, and then every fourteen days till closing 60 days. Samples for chemical analysis of the composted material were collected at 30, 60 and 90 days after the beginning of the composting process. The temperature of the piles stayed around 57 to 60 ºC in the period between the 20 to 40 days after the beginning of the composting process. The mix containing cattle rumen (RB) presented the lowest temperature after forty days. At the end of the composting the mix containing Microsept-Dust (MP) presented the lowest humidity. The C/N relation of the composts obtained was around 10/1 and 11/1. The three treatments presented pH values close to the neutrality in the mature stage. A period of sixty days seems to be sufficient to obtain a mature and stable biocompost of tobacco waste using manure independent of the addition of inoculums.

Growth response of Pterocarpus soyauxii and Lophira alata seedlings to host soil mycorrhizal inocula in relation to land use types

Deficiency in mycorrhizal inoculum in soils due to land use types (LUT) can be alleviated by quantity and quality inoculum addition. A bioassay was carried out to determine how host soil mycorrhizal inoculum influenced mycorrhizal colonization, carbon allocation and partitioning of seedlings of two native timber species of Cameroon humid forest. Seedlings ofPterocarpus soyauxii and Lophira alata were raised for six months on surface soils (0 - 20 cm) collected from early secondary forests and LUT derived from slash-and-burn agriculture and selective logging. Mycorrhizal inoculation effect (MIE) was derived. Seedlings were mainly colonized by members of the Glomaceae and Gigasporaceae, respectively, as shown by molecular typing. They generally performed poorly in soils with indigenous inoculum. But addition of soil inoculum from P. soyauxii trees favored nodulation, significantly increased mycorrhizal colonization and total biomass but decreased root-to-shoot ratios, resulting in large and positive MIE, irrespective of LUT. ln contrast, host soil inoculum of L. alata did not affect fractional mycorrhizal colonization but significantly increased total biomass and resulted in high carbon allocation to roots in low and sometimes negative MIE. Therefore, seedlings' responses to mycorrhizal inoculum depend on host soil inoculum and that could be critical for successful rejuvenation of tropical trees. Key words: Arbuscular, mycorrhiza-host, soil, inoculum-Iand use types, Pterocarpus soyauxii, Lophira alata, Cameroon.

Growth response of &lt;i&gt;Pterocarpus soyauxii&lt;/i&gt; and &lt;i&gt;Lophira alata&lt;/i&gt; seedlings to host soil mycorrhizal inocula in relation to land use types

Deficiency in mycorrhizal inoculum in soils due to land use types (LUT) can be alleviated by inoculum addition. Inoculum effects may depend both on quantity and on quality of inoculum applied. A greenhouse bioassay was carried out to determine the effect of host soil mycorrhizal inoculum on mycorrhizal colonization, carbon allocation and partitioning of seedlings of two native timber species of Cameroon humid forest, raised on surface soils (0-20 cm) collected from early secondary forests, LUT derived from slash-and-burn agriculture and selective logging. Host soil mycorrhizal inoculum was collected from the root zones of con-specific tree species. Mycorrhizal inoculation effect (MIE) was estimated as percent difference of average total biomass between seedlings grown on inoculated and non-inoculated soils. Six months-old seedlings of Pterocarpus soyauxii and Lophira alata were mainly colonized by members of the Glomaceae and Gigasporaceae, respectively, as shown by molecular typing. They generally performed poorly in soils with indigenous inoculum. But addition of soil inoculum from P. soyauxii trees favored nodulation, significantly increased mycorrhizal colonization and total biomass but decreased root-to-shoot ratios, resulting in large and positive MIE, irrespective of LUT. ln contrast, host soil inoculum of L. alata did not affect fractional mycorrhizal colonization but significantly increased total biomass, resulted in high carbon allocation to roots, in low and sometimes negative MIE. Therefore, seedlings' responses to mycorrhizal inoculum depend on host soil inoculum and that could be critical for successful rejuvenation of tropical trees. Key words. Arbuscular mycorrhiza-host soil inoculum-Iand use types- Pterocarpus soyauxii-Lophira alata -Cameroon

Natural inducement of hydrogen from food waste by temperature control

An easy and simple method of producing H 2 from food waste was devised. Although there was no inoculum addition or pretreatment, food waste was naturally decomposed and converted to H 2 when cultivated at 50–60 °C in anaerobic state. Both the highest H 2 yield of 1.79 mol H 2/mol hexose added and a production rate of 369.1 ml H 2/L/h were observed at 50 °C. While butyrate was the main by-product of the food waste cultivated at 50 °C, lactate whose producing-reaction is non-hydrogenic was dominant at 35 °C where the worst performance was observed. The degradation efficiency of volatile solids and carbohydrate was similar to 50% and 90%, respectively, at both temperatures. Polymerase chain reaction-denaturing gradient gel electrophoresis analysis clearly revealed that the role of temperature control was the microbial selection. At high temperature, the activity of indigenous lactic acid bacteria was suppressed while H 2-producing bacteria, such as Clostridium sp., Acetanaerobacterium elongatum, and Caloramater indicus, were predominantly cultivated.

Fermentation quality and nutritive value of rice crop residue based silage ensiled with addition of epiphytic lactic acid bacteria.

Silage is the feedstuff resulted from the preservation of forages through lactic acid fermentation. The aim of this study was to evaluate nutritive value, fermentation characteristics and nutrients digestibility of rice crop residue based silage ensiled with epiphytic lactic acid bacteria (LAB). The mixture of rice crop residue (RC), soybean curd residue (SC) and cassava waste (CW) in a 90: 5: 5 (on dry matter basis) ratio was used as silage material. Three treatments silage were (A) RC + SC + CW as a control; (B) RC + SC + CW + LAB inoculums from rice crop residue; (C) RC + SC + CW + LAB inoculums from king grass. Silage materials were packed into plastic silo (1.5 kg capacity) and stored for 30 days. The results showed that crude protein content in B and C silage was higher than that of silage A, but NDF content in silages B and C was lower than that of silage A. Lactic acid concentration was higher (P < 0.01) in silage C compared to silage B and A, thus pH value of silage C was lower (P < 0.01) than silage B and A. Silage C had the highest Fleigh point than that of other silages. Dry matter and organic matter digestibilities were higher in silages B and C (P < 0.01) than that of control silage. It was concluded that the addition of LAB inoculums from king grass to rice crop residue based silage resulted a better fermentation quality compared to LAB inoculums from rice crop residue. Key Words : Silage, Rice Crop Residue, Lactic Acid, In Vitro

Differential Response by Melaleuca quinquenervia Trees to Attack by the Rust Fungus Puccinia psidii in Florida.

Melaleuca quinquenervia (melaleuca) is an exotic invasive tree in Florida, Hawaii, and some Caribbean islands (1,2). Puccinia psidii (rust fungus) attacks melaleuca as well as other plants in a few genera of the Myrtaceae and Heteropyxidaceae, both members of the Myrtales (1,2). Disease occurs on succulent stems and foliage of melaleuca, causing twig dieback and defoliation (3). Melaleuca trees growing under similar field conditions exhibit susceptible or resistant reactions toward this fungus. To document this differential susceptibility of melaleuca to P. psidii, we visually evaluated 331 field-grown melaleuca trees from southeast Florida for occurrence of disease attributes: pustules (susceptible), nonpersistent halos (resistant), or asymptomatic (no macroscopic symptoms) conditions on leaves and succulent twigs during February and March when symptoms were at their peak. Percentages of trees manifesting susceptible, resistant, and asymptomatic responses to this fungus were 85.8, 13.0, and 1.2%, respectively. A screenhouse study was conducted to corroborate these observations by raising plants from composite seed sources and maintaining them in seven 3.8-liter plastic pots that were filled with commercial potting media. Nine to eleven plants per pot (with new foliage) were individually tagged, grown to 30 to 45 cm high, and spray inoculated (during February and March) with uredospores (~2 × 106/ml) obtained from melaleuca trees and suspended in water. Inoculated plants were placed on a screenhouse bench under infected trees and subjected to additional inoculum, thereby simulating field conditions. Evaluations made weekly during a 4-week period revealed that susceptible, resistant, and asymptomatic seedlings constituted 63.3, 33.6, and 3.2%, respectively, of the tagged plants. To assess the stability of these fungal and host attributes over time and space, we multiplied two P. psidii susceptible and two resistant plants from cuttings. We spray inoculated 6 to 13 rooted cuttings from each plant types with uredospores (0.8 to 2 × 106/ml) obtained from diseased melaleuca trees and suspended in water. These plants were incubated in a dew chamber for 72 to 96 h under 100% relative humidity at 19 to 23°C maintained with a 12-h fluorescent light cycle. After incubation, plants were placed randomly on a bench in a screenhouse (21 to 23°C) and evaluated weekly for symptom development during a 4-week experimental period. Noninoculated controls were maintained as well. The experiment was repeated twice. Foliage of the resistant plants developed a few incipient halos whereas 100% of the susceptible plants developed erupted uredinia and were defoliated in both replications. No detectable change in P. psidii virulence and melaleuca susceptibility patterns was observed. Despite wide host range within Myrtales, resistance to P. psidii exists within M. quinquenervia. Other P. psidii susceptible host systems of economic and environmental importance may have host/pathogen relationships similar to that of melaleuca and the selection of resistant individuals from their affected populations may be possible. Additional studies will be needed to ascertain the attributes of virulence or resistance in this rust fungus-melaleuca association.

Plant–soil feedback: experimental approaches, statistical analyses and ecological interpretations

Summary 1. Feedback between plants and soil organisms has become widely recognized as a driving force of community composition and ecosystem functioning. However, there is little uniformity in quantification and analysis of plant–soil feedback effects. Meta‐analysis suggested that the various experimental methods tend to result in different feedback values. Yet, a direct comparison of the different experimental approaches and their statistical analyses is lacking. 2. We used currently applied methods to calculate plant–soil feedback value ranges and compared their statistical analyses to those based on actual biomass data. Then, we re‐analysed a case study to compare plant–soil feedback values obtained under the same environmental conditions, but using different experimental approaches: soil sterilization, addition of soil inoculum, and soil conditioning by ‘own’ vs. ‘foreign’ plant species. 3. Different measures to calculate plant–soil feedback values were more variable in positive than in negative feedback values. Analysis of calculated feedback values that are based on treatment averages can lead to a serious inflation of type I errors. 4. In our case study, both the strength and the direction of the feedback effects depended on the experimental approach that was chosen, leading to diverging conclusions on whether feedback to a certain soil was positive or negative. Soil sterilization and addition of soil organisms yielded larger feedback than comparison of own and foreign soil. 5. Synthesis. The ecological interpretation of plant–soil feedback effects strongly depends on the experimental procedure. When the research question focuses on the strength and the sign of plant–soil feedback, soil sterilization (presumed that the side effect of increased nutrient availability can be controlled) or addition of soil inoculum is to be preferred. When the research question concerns the specificity of soil feedback effects, plant performance can be better compared between own and foreign soil. We recommend that when using calculated feedback values, the original data need to be presented as well in order to trace the cause of the effect.

Grey water biodegradability

Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different conditions in the biodegradation test. The maximum aerobic and anaerobic biodegradability and conversion rate for the different COD fractions is determined. The results show that, on average, dormitory grey water COD fractions are 28% suspended, 32% colloidal and 40% dissolved. The studied factors incubation time, inoculum addition and temperature are influencing the determined biodegradability. The maximum biodegradability and biodegradation rate differ between different COD fractions, viz. COD(ss), COD(col) and COD(diss). The dissolved COD fraction is characterised by the lowest degradation rate, both for anaerobic and aerobic conditions. The maximum biodegradability for aerobic and anaerobic conditions is 86 and 70% respectively, whereas the first order conversion rate constant, k₂₀, is 0.119 and 0.005 day⁻¹, respectively. The anaerobic and aerobic conversion rates in relation to temperature can be described by the Arrhenius relation, with temperature coefficients of 1.069 and 1.099, respectively.

Parâmetros de dimensionamento para biodigestores batelada operados com dejetos de vacas leiteiras com e sem uso de inóculo

Objetivou-se avaliar a adição de inóculo na biodigestão anaeróbia de dejetos de vacas leiteiras reciclados em biodigestores bateladas pela quantidade de biogás produzida, pela redução dos sólidos voláteis e pelos potenciais de produção de biogás para obtenção de parâmetros de dimensionamento. Foram utilizados 12 biodigestores bateladas de campo de 60 L, cujos substratos continham dejetos de vacas leiteiras, água e quatro adições de inóculo (0; 20; 30 e 40% v/v). Adotaram-se tempos médios de retenção hidráulica de 75 e 150 dias para os tratamentos contendo inóculo e sem inóculo, respectivamente, nos períodos intermediário, chuvoso e seco do ano. Maiores produções de biogás ocorreram com maiores temperaturas médias do ar. Maiores potenciais de produção de biogás foram obtidas com uso de 40% de inóculo, de 0,07 m³ de biogás por kg de dejetos, com a utilização rápida do biogás, a partir de quatro dias. Tempos de retenção hidráulica de 45 dias podem ser adotados, o que reduz o volume do biodigestor e custos de implantação.

Continuous fermentative hydrogen production from coffee drink manufacturing wastewater by applying UASB reactor

The feasibility of continuous H 2 production from coffee drink manufacturing wastewater (CDMW) was tested in two different types of reactors: a completely-stirred tank reactor (CSTR) and an up-flow anaerobic sludge blanket reactor (UASBr). While the performance in CSTR was limited, it was significantly enhanced in UASBr. The maximum H 2 yield of 1.29 mol H 2/mol hexose added was achieved at HRT of 6 h in UASBr operation. Non-hydrogenic, lactic acid was the dominant in CSTR, while butyric and caproic acids in UASBr. As caproic acid is generated by consuming acetic and butyric acids, all of which are related to H 2 production, the presence of caproic acid in the broth also indicates H 2 production, yielding 1.33 mol H 2/glucose. It was speculated that the enhanced performance in UASBr was attributed to the high concentration of biomass over 60,000 mg VSS/L in the blanket zone, which provided insufficient substrate for indigenous lactic acid bacteria (LAB) to survive. The abundance of LAB in CDMW was confirmed by natural fermentation of CDMW. That is without the addition of external inoculum, CDMW was mainly fermented into lactic acid under mesophilic condition. For the first time ever, H 2 producing granules (HPG) with diameters of 2.1 mm were successfully formed by using actual waste as a substrate.

Impact of armillaria root disease and the effect of thinning in a late‐rotation Pinus radiata plantation

SummaryIn a search for alternative methods for managing armillaria root disease in Pinus radiata plantations in New Zealand, a thinning trial was established in a 1985 planted stand infested by Armillaria novae‐zelandiae. The incidence of chronic (non‐lethal) infection rose significantly following a first thinning at age 7 years that provided additional inoculum in the form of colonized stumps. However, this effect diminished before age 19 years when the small stumps had decomposed and, contrary to expectations, a further increase in infection did not follow a second thinning at age 13.5 years, despite a high incidence of larger colonized second thinning stumps. Apparently the increased vigour and associated resistance in the released older trees was sufficient to counter any increase in inoculum potential following treatment. It therefore now appears that thinning may not be detrimental to the final crop volume in contemporary diseased second‐rotation plantations. However, this treatment furnishes no disease control benefit, and should still be deployed judiciously in heavily infested stands. There was a small, but significant reduction in volume growth on the more severely infected trees during the first 13 years in this trial, but on the larger trees later in the rotation at age 19 years there was no difference in stem volume between infection severity categories. A previous assessment based only on the earlier data therefore overestimates the impact of Armillaria in present and future pine plantations in New Zealand. Nevertheless, its widespread distribution and its demonstrated pathogenicity indicate that forest owners should be conscious of the presence of Armillaria during plantation management.