Agricultural Substrates Research Articles

Model‐Based Analysis to Increase the Substrate Efficiency of a Biogas Plant

AbstractA biogas plant is fed with agricultural substrates at an average organic loading rate of 6 kgVS per m3 fermenter volume per day and substrates with relatively high nitrogen content. This situation results in a below‐average methane yield, so the aim is to increase the substrate efficiency. An analysis of the actual condition of the plant was performed and compared with reference values. A dynamic simulation model of the biogas plant was created and adjusted with data over an operating year. The model adjustment provided a good approximation of the simulation results to the key operating variables and thus allows the evaluation of different operating variations. The effect of various measures was analyzed by simulation and it showed a potential increase in substrate efficiency of up to 15 %.

The impact of indigenous soil yeasts inoculation on bean (Phaseolus vulgaris) growth.

To determine whether the use of soil yeasts as inoculum would intervene in improving bean (Phaseolus vulgaris) growth and its symbiotic parameters, various experiments have been carried out. The effect of inoculation by soil yeasts Meyerozyma guilliermondii GP MT258984, Debaryomyces hansenii DFA MT259039, Rhodotorula mucilaginosa LIA MT259358, Rhodotorula mucilaginosa LC MT252049, along with the strain Saccharomyces cerevisiae in their cell or metabolite forms, was investigated in non-sterile (sand) and agricultural substrates (soil), in association or not with mycorrhizal fungi. The results showed that the yeast could have a beneficial effect on the bean biomass directly without increasing its nodulation and mycorrhization, or indirectly by improving those symbiotic parameters. They also revealed a very important ecological aspect and the possibility of inoculating with indigenous soil yeasts to increase the number of fertilising microorganisms, such as mycorrhizae and rhizobia, without resorting to introducing exogenous strains.

Evaluation of different substrates on growth and yield of oyster mushroom (Pleurotus florida)

An experiment was carried out to investigate the effect of different substrates on growth and yield of oyster mushroom (Pleurotus florida). Four different agricultural substrates viz., wheat straw, wheat straw + water hyacinth (1:1), maize straw, maize straw + bajra straw (1:1) were used to evaluate growth period, growth parameters and yield potential of three strains of oyster mushroom (PL-20-204, PL-20-205 and PL-20-206). Maximum average weight of fruiting bodies were recorded in bags where wheat straw+ water hyacinth was used as substrate and it was 19.30 g in case of PL-20-206 followed by 18.03 g and 16.09 g in PL-20-204 and PL-20-205 strains, respectively. Wheat straw + water hyacinth substrate showed best results among all substrates with a total yield of 900.1 kg bag−1 for PL20-206, 795.1 kg bag−1 for PL-20-204 and 731.9 kg bag−1 for PL-20-205 in three harvests. The results would be useful to mushroom growers in selecting suitable substrate for higher yield.

Cultivation of Pleurotus ostreatus on Agricultural Wastes and Their Combination

Background. Mushrooms are increasingly becoming an important component of diets worldwide, and it is of paramount importance to choose appropriate substrates to grow them. The objective of this study was to grow Pleurotus ostreatus mushroom using different agricultural substrates. Methods. Corncobs, finger millet straw, and bamboo waste were collected from different sites of the Awi Zone. The substrates were chopped into small pieces, and 500 g of their dry mass alone and their combination was measured, packed in a polythene bag, moistened, and pasteurized. The cooled substrates were inoculated with a spoon of P. ostreatus spawn brought from Debre Berhan University. The bags were placed in the growing room, and growth parameters were recorded continuously with environmental variables. The experimental setup was a complete randomized design, six treatments with three replicates. Results. The fastest spawn running phase of P. ostreatus was 28.71 ± 0.80 days, pinhead formation was 32.36 ± 0.26 days, and fruiting bodies’ formation was 5.19 ± 0.74 days after the pinhead was recorded on the corncob substrate. The highest fresh weight and biological efficiency with the significant statistical association were obtained from P. ostreatus grown on finger millet straw (253.07 ± 1.05 and 50.20 ± 0.47, respectively). The highest average number of pinheads and fruiting bodies (29.60 and 11.44, respectively) was recorded on finger millet straw. The lowest biological efficiency (20.80 ± 0.41), fresh weight (101.48 ± 0.91), number of pinheads (14.40), and number of fruiting bodies (4.25) were recorded from a mixture of corncob and bamboo waste (50% each) substrates. Conclusion. Finger millet straw is recommended as the best substrate for the cultivation of P. ostreatus. The mixed substrate of corncob and bamboo waste (1 : 1) for P. ostreatus cultivation is not encouraged due to poor growth performance.

Effect of Milky Mushroom (Calocybe indica) in Different Agricultural Residues with Different Casing Materials

Present study entitled was carried out in field irrigation lab, Department of Agricultural Engineering, Aditya Engineering College, Surampalem. In the present experiment locally available agricultural substrate paddy straw, sugarcane bagasse and cocopeat were tested with black soil and farm yard manner as casing materials. For parameters such as days required for spawn run, pinhead formation, harvest days, total yield and biological efficiency were determined. Significant results were obtained for all the experimental parameters and also for the stem length and cap diameter. Best substrate found was the paddy straw in the recent experiment with days required for spawn run (14 days), pin head formation (11.2 days), days for first harvest(50 days), stem length (8.07 cm), capdiameter (8.67 cm), first harvest (489.45 gm), second harvest (453.68 gm), total yield (925.24 gm), biological efficiency (94.31%). The next best in the order was coco peat followed by sugarcane bagasse. Hence this study confirms the suitability of paddy straw for cultivation to mushroom growers and farmyard manure with 15 cm casing thickness as substrate for its cultivation for achieving higher yield. The benefit cost ratio was estimated as 1.57.

Forage-Fed Insects as Food and Feed Source: Opportunities and Constraints of Edible Insects in the Tropics

Farmed insects can provide an alternative protein source for humans, livestock, and fish, while supporting adaptation to climate change, generating income for smallholder farmers, and reducing the negative impacts of conventional food production, especially in the tropics. However, the quantity, nutritional quality and safety of insects greatly relies on their feed intake. Tropical forages (grasses and legumes) can provide a valuable and yet untapped source of feed for several farmed insect species. In this perspective paper, we provide a viewpoint of how tropical forages can support edible insect production. We also highlight the potential of tropical forage-based diets over those using organic agricultural or urban by-product substrates, due to their versatility, low cost, and lower risk of microbial and chemical hazards. The main bottlenecks relate to dependence on the small number of farmed insect species, and in public policy and market frameworks regarding the use of edible insects as food, feed and in industrial processes. This perspective will serve interested stakeholders in identifying urgent issues at the research, ethical, marketing and policy levels that can prevent the emergence of new, insect-based value chains and business models, and the nutritional, economic and environmental benefits they promise.

Perchlorate and Agriculture on Mars

Perchlorate (ClO4−) is globally enriched in Martian regolith at levels commonly toxic to plants. Consequently, perchlorate in Martian regolith presents an obstacle to developing agriculture on Mars. Here, we assess the effect of perchlorate at different concentrations on plant growth and germination, as well as metal release in a simulated Gusev Crater regolith and generic potting soil. The presence of perchlorate was uniformly detrimental to plant growth regardless of growing medium. Plants in potting soil were able to germinate in 1 wt.% perchlorate; however, these plants showed restricted growth and decreased leaf area and biomass. Some plants were able to germinate in regolith simulant without perchlorate; however, they showed reduced growth. In Martian regolith simulant, the presence of perchlorate prevented germination across all plant treatments. Soil column flow-through experiments of perchlorate-containing Martian regolith simulant and potting soil were unable to completely remove perchlorate despite its high solubility. Additionally, perchlorate present in the simulant increased metal/phosphorous release, which may also affect plant growth and biochemistry. Our results support that perchlorate may modify metal availability to such an extent that, even with the successful removal of perchlorate, Martian regolith may continue to be toxic to plant life. Overall, our study demonstrates that the presence of perchlorate in Martian regolith provides a significant challenge in its use as an agricultural substrate and that further steps, such as restricted metal availability and nutrient enrichment, are necessary to make it a viable growing substrate.

Systematic simplification of the Anaerobic Digestion Model No. 1 (ADM1) – Laboratory experiments and model application

Due to a limited number of available measurements on agricultural biogas plants, established process models, such as the Anaerobic Digestion Model No. 1 (ADM1), are rarely applied in practise. To provide a reliable basis for model-based monitoring and control, different model simplifications of the ADM1 were implemented for process simulation of semi-continuous anaerobic digestion experiments using agricultural substrates (maize silage, sugar beet silage, rye grain and cattle manure) and industrial residues (grain stillage). Individual model structures enable a close depiction of biogas production rates and characteristic intermediates (ammonium nitrogen, propionic and acetic acid) with equal accuracy as the original ADM1. The impact of different objective functions and standard parameter values on parameter estimates of first-order hydrolysis constants and microbial growth rates were evaluated. Due to the small number of required model parameters and suitable system characteristics, simplified model structures show clear advantages for practical application on agricultural biogas plants.

Development of a heat pulse sensor for measuring matric suction on soilless substrates

Crops cultivated in greenhouse normally use soilless substrates as a growing medium. In this production process, strict control of the application of water and fertilizers is required. The availability of sensors that measure accurately and at low cost the matric suction in the culture medium enables the automation of irrigation. Currently available sensors have deficiencies such as reduced sensitivity at low suctions, interference from ambient temperature and being affected by the salinity of the substrate. The cost of commercially available sensors is also a challenge. In this context, the objective of this study was to develop a heat dissipation sensor for measuring matric suction in the range of 0 to 5 kPa, as required by most agricultural substrates. The sensor consists of two parts, the first being an active core comprised of a heat source and a temperature sensor. The second part is a specially designed porous body that comes to hydraulic equilibrium with the medium in which the sensor is inserted. The porous body was produced using sintered glass microspheres. The data acquisition system uses the Arduino Uno platform. Sensors were calibrated and tested using a coconut fiber substrate submitted to water tensions between 0 and 10 kPa, using Haines’ funnels. Good correlations were observed between temperature variations in the sensor and water tension variations in the substrate between 0 and 5 kPa. The low cost and the adequate sensitivity of the sensor indicate that it can be used in the automatic control of irrigation systems in cultivation of plants in substrates.

Maturity and stability assessment of composted tomato residues and chicken manure using a rotary drum bioreactor

ABSTRACT The efficiency of the composting process for tomato residues and chicken manure was estimated after monitoring of the rotary composting system. Physicochemical parameters and Compost Quality Index were evaluated. The tomato residues (leaves, stems, and some green and damaged fruits) were collected, cut into small pieces, moistened approximately (60–65%), and mixed with 20% chicken manure then distributed into three rotary drum bioreactors. The obtained results showed that, the temperature above 50°C was maintained for more than two days. Carbon: nitrogen (C:N) ratio was reduced from 30:1 to 19.13:1. The pH value ranged between 7 and 8.80 during the composting process, while the electrical conductivity (EC) ranged between 2.67 to 4.53 dS/m. Both compost quality parameters (Dewar and germination index) and (Solvita-CO2 and Solvita-NH3) indicated that, the final compost is stable and mature. Implications: The idea of this research revolves around assessing the maturity and stability of the compost resulting from mixing tomato residues with chicken manure, using a rotary drum bioreactor which is characterized by reducing the time of the active phase to several hours or days instead of weeks or months. Several tests related to the maturity and stability of mixture have been used to judge its quality. Also, many parameters related to this topic were monitored and discussed with many previous researches to determine the importance of benefiting from mixing the different wastes together and obtaining a good fertilizer ready for application as an agricultural substrate or a soil conditioner.

Assessment of the suitability of agricultural waste-based substrate for vermicompost production

Assessment of the suitability of agricultural waste-based substrate for vermicompost production

Biotechnology of co-fermentation of sugar by-products with typical agricultural substrates

Anaerobic digestion (AD) is a promising option for the environmentally friendly recycling of agricultural by-products. However, overloading of the digester with sugar, starch or protein might cause inhibition of the anaerobic processes. The aim of the present project was to investigate the influence of sugar beet by products on biogas yield from a typical mixture of energy crops and animal manure. The investigated substrates have been: cattle slurry, maize, sorghum and grass silage, sugar beet pulp e (SBP) and sugar beet tail silage (SBT). The difference between untreated SBT to processed SBP. All substrates were digested in 1 l eudiometer-batch digesters at 37.5°C during 28 to 38 days. The specific methane yield of mixtures and various substrates exanimated. The experiments showed that edition of sugar beet by product to energy crop and slurry mixture results in high methane yield even the achieved methane yield of the mixture was lower the expected.

Cellulase immobilized magnetic nanoparticles for green energy production from Allamanda schottii L: Sustainability research in waste recycling.

This study presents ethanol's fabrication by fermenting the golden trumpet flower (Allamanda schottii L) with the yeast strain Saccharomyces cerevisiae. The changes in different parameters during fermentation were studied and optimized while producing the ethanol and the end product was subjected to emission test study by blending petrol and ethanol. The Allamanda floral substrate contains 65% polysaccharides. The strain S. cerevisiae was obtained in the form of baker’s yeast from a domestic shop. For 100 ml of slurry, the highest bioethanol yield recorded was about 18.75 ml via optimization of different culture conditions, including a 1:8 ratio for slurry preparation, maintained under 35 ⁰C, 5.5 pH, 72 h. old inoculum with a quantity of 3.75 g 100 ml−1, fermented for120 h. The highest yield of bioethanol was acquired under the addition of urea. This technique & design is capable of industrial-scale fabrication of bioethanol by using A. schottii floral substrates. This research was conducted to fabricate ethanol by fermentation (A. schottii L) floral substrate with S. cerevisiae. The optimum physiochemical parameters required to obtain the highest yield of bioethanol from A. schottii flower by fermentation was studied. The immobilization strategy with a cheap agricultural substrate and magnetic nanoparticles were also studied. The engine performance and emission studies were done with different blends of petrol and bio-ethanol.

Optimization of xylanase production by Bacillus tequilensis strain UD-3 using economical agricultural substrate and its application in rice straw pulp bleaching

Thermo-alkali-stable xylanase producing Bacillus tequilensis strain UD-3 was isolated from the hot spring, and the biobleaching effect on rice straw pulp was evaluated. Bacillus tequilensis strain UD-3 produced xylanase (8.54 IU mL−1) employing on wheat bran. The xylanase production was increased about 2 fold after optimization of media via central composite design. The maximum xylanase activity was achieved at 8.0 pH, 50 °C temperature, and boosted at 1.0 mM concentration of metal ions such as Mn+2, Fe+3, Cu+4, and Zn+4. Furthermore, Zn+4 concoction with xylanase was evaluated for pre-bleaching of rice straw pulp in which xylanase significantly reduce the Kappa number (17.24 ± 0.02) after Xyl + Zn bleaching. A significant reduction was also observed in the reducing sugars (50%), phenolic (29.19%), hydrophobic (33.20%), and lignin compounds (35.86 and 40.48%) during the Xyl + Zn treatment of pulp samples in comparison to the only xylanase.

Innovative Hydrodynamic Disintegrator Adjusted to Agricultural Substrates Pre-treatment Aimed at Methane Production Intensification—CFD Modelling and Batch Tests

The study objective was to adjust the hydrodynamic disintegrator dedicated to sewage sludge pre-treatment (HDS) to work with agricultural substrate. This involved the development and implementation of a mathematical model of flow via the device’s domain. An innovative disintegrator (HAD—hydrodynamic disintegrator for agriculture) was designed, built, and tested based on the obtained results. The main improvements to the HDS include the implementation of shredding knives in order to overcome clogging by crushed substrate, and the application of ribs in the recirculation zone, contributing to the development of an additional structure damage zone. The challenge of this study was also to determine the operating parameters of the HDA that would provide for an increase in methane production with positive energy balance. The testing procedures, for which maize silage was selected, involved batch disintegration tests and biochemical methane potential tests. No clogging of rotor or spontaneous shutting off of the device, in other words, problems that had occurred in the HDS, were observed. The applied pre-treatment method permitted an increase in the methane potential of maize silage by 34.4%, 27.0%, and 21.6%, respectively for samples disintegrated at energy densities of 10 kJ/L, 20 kJ/L, and 35 kJ/L with net energy profit.

PRODUCTION AND CHARACTERIZATION OF AN Aspergillus niger GS1S6 PHYTASE CULTIVATED IN PHYTIC ACID-RICH AGRICULTURAL SUBSTRATES

In animal farming, improvement of growth performance through successful nutrient uptake and digestibility is critical. Phytases hydrolyze the anti-nutritive phytic acid present in grains to lesser derivatives and release the phosphorus trapped therein. Twenty-eight fungi obtained from poultry droppings, cereal-rich soils and garden soils were screened for phosphate solubilization and phytase production using Pikovskaya agar and phytase screening medium. Out of the fungi, 61% were positive for phytase producing abilities and the most proficient, isolate GS1S6 with a solubilization index of 121%, was identified as Aspergillus niger GS1S6. Optimum phytase production was achieved at a fermentation period of 120 h, pH 5.5, glucose, (NH4)2SO4 using 72 hour old fungal inoculum. Mineral supplementation of natural agricultural substrates enhanced phytase production (1000U/L) the most in milled sesame seed medium. The ~31-38 KDa partially purified and characterized enzyme demonstrated optimum activities at 55oC and pH 6.0, while cationic inclusions reduced phytase activities. The Km and Vmax were low (1.308 mM and 0.077 mM/mL/min) from Linear-weaver plot with increasing substrate concentration implying that A. niger GS1S6 phytase may efficiently mineralize phytic acid and therefore hold great prospect for its commercialization.

Effect of codon optimization and promoter choice on recombinant endo-polygalacturonase production in Pichia pastoris

Pectinase is one of the most widely used enzymes in different fields of food industry for different purposes, such as clarification of fruit juice, extraction of vegetable oil and saccharification of agricultural substrates. The aim of this study is to produce recombinant pectinase and evaluate the effect of codon optimization and promoter selection on production.In this study, the gene encoding pectinase in Aspergillus niger was optimized according to the codon usage of Pichia pastoris. Within the scope of the study, codon-optimized and native (non-codon-optimized) pectinase genes were transferred to P. pastoris X33 strain and expressed under the regulation of methanol-inducible AOX1 and ethanol-inducible ADH2 promoter.As a result of the study, the promoter and codon combination which exhibited the highest production level was determined as the ADH2 and codon-optimized pectinase yielding an enzyme activity of 42.33 U/mL. The best producer clone was cultured in 400 mL media in 2 L shake-flask and the enzyme was purified by His-tag method. The optimum working conditions of the purified enzyme was 50 °C and pH 5.0, and after incubation at 60 °C for 1 -h, enzyme activity was maintained at 60% level. The Michelis–Menten constant (Km) and maximal velocity (Vmax) of the purified recombinant pectinase were 6.9 mg/mL and 67.57 μmol/mg/min, respectively.

Composition of Synthesized Cellulolytic Enzymes Varied with the Usage of Agricultural Substrates and Microorganisms.

We evaluated various agricultural lignocellulosic biomass and variety of fungi to produce cellulolytic enzymes cocktail to yield high amount of reducing sugars. Solid-state fermentation was performed using water hyacinth, paddy straw, corn straw, soybean husk/tops, wheat straw, and sugarcane bagasse using fungi like Nocardiopsis sp. KNU, Trichoderma reesei, Trichoderma viride, Aspergillus flavus, and Phanerochaete chrysosporium alone and in combination to produce cellulolytic enzymes. Water hyacinth produced (Uml-1) endoglucanase (51.13) and filter paperase (0.55), and corn straw produced (Uml-1) β-glucosidase (4.65), xylanase (113.32), and glucoamylase (41.27) after 7-day incubation using Nocardiopsis sp. KNU. Production of cellulolytic enzymes was altered due to addition of various nitrogen sources, metal ions, vitamins, and amino acids. The maximum cellulolytic enzymes were produced by P. chrysosporium (endoglucanase; 166.32Uml-1 and exoglucanase; 12.20Uml-1), and by T. viride (filter paperase; 1.57Uml-1). Among all, co-culture of T. reesei, T. viride, A. flavus, and P. chrysosporium showed highest β-glucosidase (17.05Uml-1). The highest xylanase (1129Uml-1) was observed in T. viride + P. chrysosporium co-culture. This study revealed the dependency on substrate and microorganism to produce good quality enzyme cocktail to obtain maximum reducing sugars.

Evaluating the validity of rice straw as a suitable agricultural substrate for common bean plants under net house conditions

Evaluating the validity of rice straw as a suitable agricultural substrate for common bean plants under net house conditions

Evaluating the validity of rice straw as a suitable agricultural substrate for common bean plants under net house conditions

This research paper was carried out in the net house at the Central Laboratory for Agricultural Climate (CLAC), throughout two tested seasons of 2017/2018 and 2018/2019 to investigate the effect of using rice straw as a growing substrate (bale & ditch) on vegetative growth, yield and water use efficiency (WUE) of two cultivars of common bean (Phaseolus vulgaris L.), Hilda as indeterminate variety and Nebraska determinate variety compared to conventional cultivation in soil. Seedlings were cultivated at 1st September in two growing seasons. Study was included three treatments with 4 replicates arranged in a randomized complete block design. Results indicated that plants grown on ditch rice straw treatment as substrate reflected the highest positive effect on vegetative growth characters (plant length, number of leaves/plant and stem diameter), leaves mineral content of N. P. K and yield and its components (total yield/plant, and fiber content on pods) at both studied cultivars. While, the lowest negative effect on those characters was observed with bale rice straw treatment. Moreover, raised bed clay (control) treatment was replaced in second place after the treatment of ditch rice straw. In addition, cultivation into straw ditch consumed lower quantities of water than other treatments. Finally, straw ditch substrate may be recommended for increasing common bean productivity and decreasing water utilization beneath net house conditions.