Digestibility Yield Research Articles

Impact of biochar prepared at different pyrolysis temperatures on the methane production and microbial community structure of food waste anaerobic digestion

Biochars were prepared through the pyrolysis of sawdust at 300 °C, 500 °C, and 700 °C, respectively, under oxygen-limited conditions. The basic physicochemical properties of biochars were explored by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), surface area and porosity analyzer (BET), and Fourier-transform infrared spectrometer (FTIR). The effects of biochar addition on the methane yield and microbial community structure of anaerobic digestion of food waste were also investigated. SEM images showed that biochar had a honeycomb-like pore structure, EDS analysis showed that the C content in the biochar tended to increase, and the O contents tended to decrease with the increasing temperature. The specific surface area of biochars increased from 1.2014 m2/g (300 °C) to 326.8435 m2/g (700 °C). FTIR analysis showed that the number of different surface functional groups decreased with the increasing temperature. The addition of biochar could increase the cumulative methane volume by 11.63%–25.18%. High-throughput sequencing results showed that biochar addition could increase the relative abundance of Bacteroidetes, Chloroflexi, Firmicutes, Proteobacteria, and Spirochaetota, which were associated with the degradation of refractory organic matters. Meanwhile, biochar addition could enrich the relative abundance of methanogens participating in direct electron transfer (Methanosaeta and Methanosarcina), and methanogens producing methane through multiple pathways (Methanobacterium and Methanosarcina). The addition of biochar derived at 700 °C significantly increased the relative abundance of Methanobacterium and Methanosarcina from 1.96% and 0.70% (control group) to 32.68% and 64.69%, respectively and improved methane production by transforming acetoclastic/hydrogenotrophic methanogenic pathways to more metabolically diverse methanogenic pathways.

Feeding frequency efficacy on biogas yield of oily substrate anaerobic digestion in continuous stir tank reactor.

Anaerobic treatment of oily substrate, known as grease trap waste (GTW), was investigated for its practicability via continuous stirred tank reactor (CSTR) at different operating conditions and selected recovery strategies of feeding frequency efficacy. This study determine the performance of feeding frequency efficacy, namely feeding every 24 hours (R24H) and feeding every 12 hours (R12H). Under organic loading rate (OLR) of 2.2 gCOD/L.day, R12H exhibited methane composition of 57%, methane production rate of 0.27 LCH4/L.day, and methane yield of 0.14 LCH4/gCODremoved. At the same OLR, R24H recorded methane composition of 60%, methane production rate of 0.29 LCH4/L.day and similar methane yield as R12H. Findings indicated that R24H showed performance comparable to that of R12H. Given minor variation observed in performance, it is recommended that plant operators may consider scheduling two feedings per day for low loading conditions and switch to one feeding per day for higher loading conditions. This strategy is designed to balance the system and prevent shock loads, which could lead to plant shutdowns. This mechanism will induce their conversion to volatile fatty acids (VFAs); thus, reducing the risk of acid accumulation and pH drops, which could inhibit methanogens to produce methane, especially for oily substrate.

Source-Separated Industrial Wastewater Is a Candidate for Biogas Production through Anaerobic Digestion

Anaerobic digestion is a potential treatment for industrial wastewater that provides valuable end-products, including renewable energy (biogas). However, waste streams may be too variable, too dilute at high volumes, or missing key components for stable digestion; all factors that increase costs and operational difficulty, making optimisation crucial. Anaerobic digestion may benefit from process intensification, particularly the novel combination of high-strength source-separated wastewater to minimise volume, together with the use of biosolids biochar as a chemical and microbial stabiliser. This study investigates the stability, yield, and microbial community dynamics of the anaerobic digestion of source-separated industrial wastewater from a food manufacturer and a logistics company, using biosolids biochar as an additive, focusing on gas and volatile fatty acid (VFA) production, process stability, and the microbial community using bench-scale semi-continuous reactors at 30- and 45-day hydraulic retention time (HRT). While gas yields were lower than expected, stability was possible at high HRT. Methane production reached 0.24 and 0.43 L day−1 per litre reactor working volume at 30- and 45-day HRT, respectively, despite high VFA concentration, and was linked to the relative abundance of Methanosarcina in the microbial community. Interactions between substrate, VFA concentration, and the microbial community were observed. Biochar-assisted anaerobic digestion holds promise for the treatment of source-separated wastewater.

Registration of the Oat (Avena sativa) Variety "Walqaa" for Vertisols in the Central Highlands of Ethiopia

In this study, fifteen oat varieties including the standard checks were evaluated for agro-morphological traits, nutritional qualities, disease, and insect pest reactions during the main cropping seasons of 2015- 2018. Based on the overall performance, two best-performing oat varieties (CI-1742 and SRCPX80Ab2596) were selected and verified with the two standard checks at the Kuyu and Ginchi sub-site of Holetta Agricultural Research Center during the main cropping season of 2018. The overall mean result indicated that the released variety, Walqaa (SRCPX80Ab2596), showed the highest mean DM yield followed by the recent check (SRCPX80Ab2291) while the check variety (CI-8251) which was released earlier and commonly used for vertisol gave the lowest DM yield. Walqaa (SRCPX80Ab2596) had the highest percent increase in DM yield, CP yield, and digestible yield advantages over the standard check variety (CI-8251) which was released earlier and commonly used for vertisol conditions. Similarly, the Walqaa (SRCPX80Ab2596) had a relatively better percent increase in DM yield, CP yield, and digestible yield advantages over the recently released variety (SRCPX80Ab2291). Moreover, the Walqaa (SRCPX80Ab2596) had seeds yield advantage over the earlier released variety (CI-8251). The nutritional qualities indicated that the candidate varieties had advantages over the standard check variety (CI-8251) in terms of the leafto-stem ratio, CP, and IVDMD contents. Generally, the Walqaa (SRCPX80Ab2596) had a relatively better leaf-tostem ratio, CP, and IVDMD advantages over the standard check variety (CI-8251). The national variety releasing committee evaluated the varieties at field conditions in October 2018. Based on their evaluation result, oat variety Walqaa (SRCPX80Ab2596) was officially released in November 2019 for production in the high altitude areas and similar agro-ecologies of the country. The pre-basic and basic seeds of the released variety Walqaa (SRCPX80Ab2596) are maintained by the feeds and nutrition research program of Holetta Agricultural Research Center. Keywords: Oat, quality, variety release, variety verification, yield

Cheaper, faster, simpler trypsin digestion for high-throughput targeted protein quantification

IntroductionLC-MS-based methods for protein quantification have a stigma of being relatively expensive and low-throughput. This is partly due to the cost and speed of trypsin digestion, which has primarily focused on advancements in research-based biomarker discovery applications that rely on protein/peptide identifications rather than clinical biomarker quantification. However, there is a need for simple, fast, and reproducibly efficient surrogate peptide recovery in clinical biomarker quantification. MethodsMultiple methodologies were evaluated to enhance tryptic digestion for the analysis of thyroglobulin, a prototypical serum protein biomarker. The main criteria for assessment were the yield and speed of formation of surrogate peptides. Various factors such as different additives, types of trypsin, microwave- and pressure-assisted systems, and enzyme concentration were considered as key variables, in addition to digestion time. ResultsIt was observed that digestion additives/denaturants had a significant impact on the speed and yield of digestion for each surrogate peptide. Increasing the concentration of trypsin alone was found to accelerate digestions appreciably for most surrogate peptides, without affecting the yield. However, the use of sequencing-grade trypsins and microwave/pressure-assisted systems did not offer significant advantages over the use of 'standard-grade' TPCK-treated trypsin in combination with a conventional incubator, once digestion time and additive had been optimized. ConclusionWe have dispelled the notion that trypsin digestion is inherently slow and expensive for targeted quantification of serum proteins. Additionally, we have established a groundwork for experimentation that can pave the way for the creation of efficient trypsin digestion protocols, aiming to optimize yield, speed, and cost. It is our hope that these advancements will promote the wider incorporation of such assays in clinical laboratories.

Effects of Tenebrio molitor protein emulsion on the properties, and structure of myofibrillar protein gel

In this study, the effects of Tenebrio molitor protein (TMP) emulsions (TMPEs) on the gel properties, and protein structure of chicken myofibrillar proteins (MPs) were investigated. The gaps in the gel were filled by the addition of TMPs, and the stability of the gel structure was optimized using the close combination of TMPs and MP. Furthermore, the viscoelasticity, gel strength, gel whiteness, water holding capacity, and digester yield of the MP gel were enhanced after adding 4–8%TMPEs. Specifically, 8%TMPEs improved the energy storage modulus of the gel, and the MP gel exhibited thorough and uniform three-dimensional network structure. Moreover, the addition of 8%TMPEs induced protein structure development, its β-sheet content reached 45.13 ± 1.40%, and WHC reached 80.82%. Moreover, the addition of 8% TMPEs enhanced the hydrophobic interactions in the MP gel. However, the introduction of excess TMPEs (10%) reduced the continuation of the gel network and shaped the gel structure. Overall, TMPEs can enhance the molecular structure of the MP gels and promote intermolecular interactions, offering significant potential for applications in the meat industry.

Hydrothermal pretreatment based on biogas slurry recycling to improve methane yield of typical plant wastes from South China

Lignin content of feedstock contributed more for the biomass recalcitrance despite of the comprehensive effect from multiple physical and chemical characteristics based on the anaerobic digestion analysis of 16 plant wastes from South China. With the objective of improving anaerobic digestion performance of mixed fruit shell, hydrothermal pretreatment based on biogas slurry recycling (HPBSR) was proposed. Compared with traditional hydrothermal pretreatment, the lignin content of mixed fruit shell was reduced by 4.51–21.13% after HPBSR. The soluble chemical oxygen demand of liquid fraction under 200 ℃ increased by 87.45% relative to the control group with biogas slurry. And the cumulative methane yield of anaerobic digestion was 129.97 mL/gVS, which was 45.01% and 18.78% higher than the control group without treatment and the hydrothermal pretreatment group, respectively. Moreover, the HPBSR experimental group did not produce anaerobic digestion inhibitors (furfural and 5-hydroxymethylfurfural), and the higher humic acid concentration would be another possible reason for the improvement of methane yield. The related results will provide insights into the resource utilization of biogas slurry.

Microstructural diversity and digestion yields of select bituminous and subbituminous coals as raw material candidates for carbon fiber precursor production

This work investigates the use of coals as raw materials for carbon fiber precursor production as a new alternative to coal utilization. Coal being a highly complex and heterogeneous material with different macerals and minerals complicates this task. Extensive microstructural characterization as well as preliminary digestion studies are performed on three bituminous coals (Herrin and Springfield from the Illinois Basin and the Blue Gem from the Central Appalachians) and one subbituminous coal from the Powder River Basin (Monarch), as raw material candidates. The subbituminous coal was richer in oxygen, lower in sulfur, and had a higher volatile matter yield. Microstructural investigations were performed using X-ray diffraction, X-ray/neutron computed tomography, scanning electron microscopy with energy dispersive spectroscopy, and petrology. Mild solvent extraction studies were conducted using creosote and decant oil as solvents in microreactors. The extraction yield was sensitive to temperature and time (350 to 450 °C between 30 and 120 mins.) for both creosote and decant oil digestions. While the Blue Gem coal had more desirable microstructural properties with less mineral content and cleaner macerals, it had the lowest coal conversion to quinoline soluble ‘liquid’ (of the bituminous coals). The lower coal conversion yield was hypothesized to be connected to the lack of FeS2 which could act as a catalyst when Fe is liberated from the structure under solvent extraction conditions. The Herrin and Springfield coals revealed similar microstructures and coal conversion efficiencies (higher than Blue Gem). These coals were the most promising candidates for further examination from this first approximations study. The subbituminous Monarch coal, however, was deemed less suitable due to poor coal conversion and less desirable microstructures. Additionally, the presented results with combined microstructural data from multiple length scales established a framework necessary for a first approximations study in this new coal utilization approach.

Biochemical and biohythane production from anaerobically digested water plant by hydrothermal liquefaction/gasification

Water hyacinth (Eichhornia crassipes) was anaerobically digested with waste sludge in a batch system at varying total solid (TS) contents (3.3–8.3%) and temperatures (35–55 °C). Then, the high organic content of digested biomass was utilized for hydrothermal liquefaction/gasification in the batch reactor system at different temperatures (200–600 °C) to yield biofuels and biochemicals. Hydrothermal liquefaction/gasification was performed in sub- and super-critical water (above 374 °C and 221 bar) conditions. Prevailing products are some biochemical compounds (carboxylic acids, furfurals, aldehyde/ketones, phenols etc.) at lower temperatures (200–300 °C) while biohythane (total of hydrogen and methane) gaseous fuel are produced at higher temperatures (400–600 °C). The highest carbon gasification efficiency (73 g C in product/g C in feed) was obtained at 600 °C with the sample that has a high anaerobic digestion efficiency (digested at 6.3 TS% at 35 °C). The highest carbon liquefaction efficiency (37.2 g C in product/g C in feed) was obtained at 200 °C with the sample which has a low anaerobic digestion yield (digested at 8.3 TS% at 35 °C).

Precise control of water stress in the field reveals different response thresholds for forage yield and digestibility of maize hybrids.

With dwindling global freshwater supplies and increasing water stress, agriculture is coming under increasing pressure to reduce water use. Plant breeding requires high analytical capabilities. For this reason, near-infrared spectroscopy (NIRS) has been used to develop prediction equations for whole-plant samples, particularly for predicting dry matter digestibility, which has a major impact on the energy value of forage maize hybrids and is required for inclusion in the official French catalogue. Although the historical NIRS equations have long been used routinely in seed company breeding programmes, they do not predict all variables with the same accuracy. In addition, little is known about how accurate their predictions are under different water stress-environments. Here, we examined the effects of water stress and stress intensity on agronomic, biochemical, and NIRS predictive values in a set of 13 modern S0-S1 forage maize hybrids under four different environmental conditions resulting from the combination of a northern and southern location and two monitored water stress levels in the south. First, we compared the reliability of NIRS predictions for basic forage quality traits obtained using the historical NIRS predictive equations and the new equations we recently developed. We found that NIRS predicted values were affected to varying degrees by environmental conditions. We also showed that forage yield gradually decreased as a function of water stress, whereas both dry matter and cell wall digestibilities increased regardless of the intensity of water stress, with variability among the tested varieties decreasing under the most stressed conditions. By combining forage yield and dry matter digestibility, we were able to quantify digestible yield and identify varieties with different strategies for coping with water stress, raising the exciting possibility that important potential selection targets still exist. Finally, from a farmer's perspective, we were able to show that late silage harvest has no effect on dry matter digestibility and that moderate water stress does not necessarily result in a loss of digestible yield.

Potential of hydrochar/pyrochar derived from sawdust of oriental plane tree for stimulating methanization by mitigating propionic acid inhibition in mesophilic anaerobic digestion of swine manure

VFAs accumulation in anaerobic digestion systems can lead to disturbance of the acid base balance, which has brought major challenges for methane production. Meanwhile, less research explored the potential of biochar derived from wood wastes of oriental plane tree (Platanus orientalis L.) for stimulating methanization in mesophilic anaerobic digestion. In this study, the effects of pyrochar and hydrochar derived from sawdust of oriental plane tree on mesophilic anaerobic digestion of swine manure were compared for the first time. Fourier infrared transform analysis indicated that more functional groups existed on the surface of hydrochar, whereas higher ash content and BET specific surface area were found in pyrochar. The maximum methane production rate during anaerobic digestion was observed in the pyrochar treatment, which increased by 59.5% compared with the control without biochar. Although stimulative effects on dissolved organic carbon and volatile fatty acids production were both observed in the pyrochar and hydrochar treatments, the pyrochar treatment was much easier to trigger multipath methanogenesis and direct interspecific electron transport and subdue propionic acid accumulation compared to the hydrochar treatment. Moreover, redundancy analysis indicated that the variations in acetic acid and dissolved organic carbon were mostly associated with microbial succession. These results suggest that pyrochar has better promoting effects than HC in terms of methane generation and propionic acid inhibition alleviation owing to its special porous structures, functional groups (e.g., C=O, C–O and O–H), and physicochemical properties. These excellent properties play a greater role in recruiting functional archaea and bacteria to regulate the levels of volatile fatty acids and dissolved organic carbon to enhance the methane yield of anaerobic digestion. This study provides novel and valuable information for further engineering applications of pyrochar and hydrochar derived from sawdust of oriental plane tree in energy production and environmental waste treatment.

Effect of the season on the production and chemical properties of fish protein hydrolysates and high-quality oils obtained from gurnard (Trigla spp.) by-products

Currently valorization of fish discards by-products is becoming fundamental for the sustainable management of fisheries and seafood transforming industries. Thus, we have studied the changes in the production and chemical properties of fish protein hydrolysates (FPH) and oils from by-products (heads (He) and skins + bones (SB)) of gurnard (Trigla spp.) captured at different seasons. Hydrolyses were performed by Alcalase (2.5 mL/kg of by-product) at pH 8.60, 60.6 °C, 200 rpm, for 3 h. Seasonality effect was not significant in the majority of FPH properties, obtaining high digestion yields and excellent amino acid contents (more than 43% of essential amino acids per total amino acids in He). However, the maximum degree of hydrolysis for He were higher (24–26.5%) than observed for SB (19–23.6%). In the case of oil, concomitantly recovered to the production of hydrolysates, the yield of recovery was largest in SB landing on autumn (89 mL/kg SB) and winter (67 mL/kg SB), and the best content in ω-3 fatty acids was also found in autumn (257 g/kg oil). In general, FPH and oil from gurnard residues were excellent in productive, compositional and nutritional terms, indicating their valuable interest as potential food and nutraceutical ingredient.

Enhanced conversion mechanism of Al-goethite in gibbsitic bauxite under reductive Bayer digestion process

The conversion mechanism of Al-goethite under the action of different additives (lime or reductant for typical or reductive Bayer digestion) was investigated by thermodynamic calculation, XRD, and SEM−EDS. The results show that the formation of Fe-substituted hydrocalumite is crucial to converting Al-goethite to hematite during Bayer digestion by adding lime. However, the conversion proceeds more easily under the action of reductant due to the rapid formation of magnetite. Additionally, Bayer liquor composition significantly affects the product composition and also the conversion rate of Al-goethite. Compared to typical Bayer digestion with Al-goethite containing gibbsitic bauxite as raw material, the red mud yield of reductive Bayer digestion decreases from 39.02% to 31.19%, and the grade of TFe in red mud increases from 41.66% to 53.80%.

Methanosarcina thermophila bioaugmentation and its synergy with biochar growth support particles versus polypropylene microplastics in thermophilic food waste anaerobic digestion

Both biochar supplementation as well as bioaugmentation have been shown in literature to improve the methane yield of anaerobic digestion. In this study, the combination of both are evaluated by growing Methanosarcina thermophila on biochar support particles prior to augmentation of thermophilic food waste anaerobic digestion. Biochar stand alone, bioaugmentation solely, a combination of both added separately or grown together, and utilizing polypropylene (PP) microplastics as growth support instead were all tested when starting up a thermophilic process from mesophilic inoculum. Methanosarcina thermophila and biochar supplementation displayed synergy, with 5% M. thermophila on 1 g/L biochar presenting a 32% increase in specific methane yield over the control. Double the bioaugmentation dosage/concentration was also trialled with a thermophilic inoculum, and 10% M. thermophila grown on 2 g/L biochar displayed the best results with a 20% increase specific methane yield from its control standard.

Doses and Timing of 2, 4-D Application for Broadleaf Weed Control, Botanical Compositions, Productivity, and Nutritive Value of Natural Pasture

2,4-Dichlorophenoxyacetic acid (2,4-D) is among the most common and inexpensive herbicides used to control broadleaf weeds in natural pasture. However, different studies have pointed out the risk of forage injury. Consequently, no research data on the productivity and nutritive value of natural pasture in response to different rates and times of 2,4-D application exists in Ethiopia. Therefore, this study was conducted to investigate natural pasture yield and nutritive response to 2,4-D application at different rates (1, 1.5, and 2 L·ha−1) and time (mid-July, early, and mid-August) with control. The experiment was designed as a factorial randomized complete block design with three replicates for two years. Grasses and legume proportions in the pasture were significantly influenced by the rate and time ( P < 0.05 ) of 2, 4-D application and their interaction ( P < 0.001 ). Interaction of rate and time of 2, 4-D application had a significant ( P < 0.05 ) influence on dry matter yield of legumes and non-significant ( P > 0.05 ) effect on forage portions (grasses + legumes) and grasses. Crude protein and in vitro dry matter digestible yield of pasture forage portions were not significantly ( P > 0.05 ) influenced by the rate and time of 2, 4-D application and their interaction. Weed dry matter yield was significantly affected by the interaction of rate and time of 2, 4-D application and mid-July application at 1.5 and 2 L·ha−1 gave the lowest yield. Therefore, to produce optimum quality and quantity of forage from natural pasture, the application of 2, 4-D in mid-July at 1.5 L·ha−1 is recommended.

Methane Production Potential from Apple Pomace, Cabbage Leaves, Pumpkin Residue and Walnut Husks

Circular economy aims to eliminate organic waste through its transformation, composting and processing into other products or energy. The main aim of the study was to determine the specific methane yield (SMY) of anaerobic digestion (AD) of four different fruit and vegetable residues (FVR). In addition, the reduction in greenhouse gas (GHG) emissions was calculated based on the assumption that maize will be replaced by the FVR as a feedstock for biogas production. The SMY of four residues (apple pomace, cabbage leaves, pumpkin peels and fibrous strands and walnut husks) was measured in the biomethane potential test (BMP) in wet anaerobic digestion technology. The highest SMY (297.81 ± 0.65 NL kgVS−1) was observed for cabbage leaves while the lowest SMY (131.07 ± 1.30 kgVS−1) was found for walnut husks. The concentrations of two inhibitory gasses (NH3 and H2S) in biogas were low and did not affect the AD process. Only biogas produced from cabbage leaves was characterised by higher NH3 and H2S concentrations resulting from the highest protein concentration in this waste. FVR used as feedstock in biogas production may decrease the area of maize cultivation. Therefore, the GHG emissions from maize cultivation will be reduced. In Poland only, the use of four studied FVR as feedstock for biogas production would contribute to the reduction of GHG emissions by 43,682 t CO2 eq.

Effect of exogenous protease on growth performance and meat quality in broilers reared on fishmeal-based diets

This study determined the effect of protease supplementation in fishmeal-based diets on growth performance and meat quality of commercial broiler birds. Four hundred and thirty-two (432) day-old broiler chicks were divided into 36 experimental units of 12 chicks each. Nine experimental diets were formulated using three levels (0%, 25%, and 50%) of the fishmeal as protein source, on protein equivalent basis, with or without alkaline protease (CIBENZA® DP100), and with overestimation of nutritional value based on the enhanced digestibility coefficient (EDC) concept because of the use of alkaline protease. Feed consumption and bodyweight were measured weekly. On the last day of the trial, two birds from each pen were picked and processed for carcass and meat quality parameters. Data were analysed by analysis of variance in a 3 x 3 factorial arrangement of completely randomized design. Weight gain and feed conversion ratio (FCR) were improved in the birds with 25% fishmeal as a replacement for soybean meal (SBM) and enzyme supplementation. Similarly, higher protein digestibility, dressing percentage and thigh meat yield were observed in birds fed diets with 25% fishmeal with added enzyme. In the blood biochemical profile, uric acid levels were lower, and cholesterol and triglyceride were higher in the group fed diets with 25% fishmeal with EDC and enzyme. The addition of protease enzyme to the diet with 25% fishmeal improved growth performance, crude protein digestibility and carcass characteristics.

Artificial Neural Network (ANN) Modelling for Biogas Production in Pre-Commercialized Integrated Anaerobic-Aerobic Bioreactors (IAAB)

The use of integrated anaerobic-aerobic bioreactor (IAAB) to treat the Palm Oil Mill Effluent (POME) showed promising results, which successfully overcome the limitation of a large space that is needed in the conventional method. The understanding of synergism between anaerobic digestion and aerobic process is required to achieve maximum biogas production and COD removal. Hence, this work presents the use of artificial neural network (ANN) to predict the COD removal (%), purity of methane (%), and methane yield (LCH4/gCODremoved) of anaerobic digestion and COD removal (%), biochemical oxygen demand (BOD) removal (%), and total suspended solid (TSS) removal (%) of aerobic process in a pre-commercialized IAAB located at Negeri Sembilan, Malaysia. MATLAB R2019b was used to develop the two ANN models. Bayesian regularization backpropagation (BR) showed the best performance among the 12 training algorithms. The trained ANN models showed high accuracy (R2 > 0.997) and demonstrated good alignment with the industrial data obtained from the pre-commercialized IAAB over a 6-month period. The developed ANN model is subsequently used to create the optimal operating conditions which maximize the output parameters. The COD removal (%) was improved by 33.9% (from 68.7% to 92%), while the methane yield was improved by 13.4% (from 0.23 LCH4/gCODremoved to 0.26 LCH4/gCODremoved). Sensitivity analysis shows that COD inlet is the most influential input parameters that affect the methane yield, anaerobic COD, BOD and TSS removals, while for aerobic process, COD removal is most affected by mixed liquor suspended solids (MLSS). The trained ANN model can be utilized as a decision support system (DSS) for operators to predict the behavior of the IAAB system and solve the problems of instability and inconsistent biogas production in the anaerobic digestion process. This is of utmost importance for the successful commercialization of this IAAB technology. Additional input parameters such as the mixing time, reaction time, nutrients (ammonium nitrogen and total phosphorus) and concentration of microorganisms could be considered for the improvement of the ANN model.

Dry anaerobic digestion of ammoniated straw: Performance and microbial characteristics

This paper explores the influence of the mixing ratio of ammoniated straw to biogas residue on the stability and methane yield of dry anaerobic digestion and analyzes the structure of the microbial community with digestion time. Five reactors containing ammoniated straw and swine manure biogas residue at ratios of 5:1, 4:2, 3:3, 2:4 and 1:5 (total solids) were constructed, and neither total ammonia nitrogen nor free ammonia nitrogen was inhibited. Three reactors produced gas successfully. The reactor with a ratio of 3:3 (R3-3) yielded the best methane production, with a cumulative methane production of 115.13 mL/(g·VSadded). Analysis of the R3-3 microbial community showed that bacteria were dominant species. Archaea, mainly Methanosarcina, played an important role in anaerobic digestion and methane production. Methanobacterium, with high acid tolerance, was positively related to total volatile fatty acids (TVFA), playing a key role in preventing the acidification of the anaerobic digestion system.

Genetic Dissection and Quantitative Trait Loci Mapping of Agronomic and Fodder Quality Traits in Sorghum Under Different Water Regimes.

Livestock provides an additional source of income for marginal cropping farmers, but crop residues that are used as a main source of animal feed are characteristically low in digestibility and protein content. This reduces the potential livestock product yield and quality. The key trait, which influences the quality and the cost of animal feed, is digestibility. In this study, we demonstrate that sorghum breeding can be directed to achieve genetic gains for both fodder biomass and digestibility without any trade-offs. The genotypic variance has shown significant differences for biomass across years (13,035 in 2016 and 3,395 in 2017) while in vitro organic matter digestibility (IVOMD) showed significant genotypic variation in 2016 (0.253) under drought. A range of agronomic and fodder quality traits was found to vary significantly in the population within both the control and drought conditions and across both years of the study. There was significant genotypic variance (σg2) and genotypic × treatment variance (σgxt2) in dry matter production in a recombinant inbred line (RIL) population in both study years, while there was only significant σg2 and σgxt2 in IVOMD under the control conditions. There was no significant correlation identified between biomass and digestibility traits under the control conditions, but there was a positive correlation under drought. However, a negative relation was observed between digestibility and grain yield under the control conditions, while there was no significant correlation under drought population, which was genotyped using the genotyping-by-sequencing (GBS) technique, and 1,141 informative single nucleotide polymorphism (SNP) markers were identified. A linkage map was constructed, and a total of 294 quantitative trait loci (QTLs) were detected, with 534 epistatic interactions, across all of the traits under study. QTL for the agronomic traits fresh and dry weight, together with plant height, mapped on to the linkage group (LG) 7, while QTL for IVOMD mapped on to LG1, 2, and 8. A number of genes previously reported to play a role in nitrogen metabolism and cell wall-related functions were found to be associated with these QTL.