Plant Productivity Research Articles

Pinpointing the causal influences of stomatal anatomy and behavior on minimum, operational, and maximum leaf surface conductance.

Leaf surface conductance to water vapor and CO2 across the epidermis (gleaf) strongly determines rates of gas exchange. Thus, clarifying the drivers of gleaf has important implications for resolving mechanisms of photosynthetic productivity and leaf and plant responses and tolerance to drought. It is well recognized that gleaf is a function of the conductances of the stomata (gs) and of the epidermis + cuticle (gec). Yet, controversies have arisen around the relative roles of stomatal density (d) and size (s), fractional stomatal opening (α; aperture relative to maximum) and gec in determining gleaf. Resolving the importance of these drivers is critical across the range of leaf surface conductances, from strong stomatal closure under drought (gleaf, min), to typical opening for photosynthesis (gleaf, op), to maximum achievable opening (gleaf, max). We derived equations and analyzed a compiled database of published and measured data for approximately 200 species and genotypes. On average, within and across species, higher gleaf, min was determined ten times more strongly by α and gec than by d, and negligibly by s; higher gleaf, op was determined approximately equally by α (47%) than by stomatal anatomy (45% by d, and 8% by s), and negligibly by gec; and higher gleaf, max was determined entirely by d. These findings clarify how diversity in stomatal functioning arises from multiple structural and physiological causes with importance shifting with context. The rising importance of d relative to α, from gleaf, min to gleaf, op, enables even species with low gleaf, min, which can retain leaves through drought, to possess high d and thereby achieve rapid gas exchange in periods of high water availability.

ZmPGIP1 regulates stem strength by enhancing lignin and cellulose biosynthesis in Arabidopsis thaliana

Polygalacturonase inhibiting proteins (PGIPs) are typical leucine-rich repeat (LRR) proteins that inhibit the activity of polygalacturonase (PG) in pathogens, but their function in promoting to plant stem development has been less studied. In this study, the PGIP gene from Zea mays was cloned and heterologously expressed in Arabidopsis thaliana, and then the plant phenotypes were observed and a set of physiological and biochemical indicators were measured. The results indicate that the ZmPGIP1 protein is expressed both in the cell membrane and cell wall. Our research observed that the heterologous expression of ZmPGIP1 significantly increased the production of lignin, cellulose and hemicellulose in transgenic lines. The stems of transgenic plants also showed a thicker cortical tissue. The increase in lignin deposition observed during histochemical staining suggests that the ZmPGIP1 gene may improve plant mechanical strength. These were tightly associated with the upregulated expression of lignin/cellulose-synthesis genes (C4H, C3H, F5H, PAL1/3, CCR1, CAD1-3/9, CCOMT, MYB58, CESA1/10) to enhance plant cell wall strength in transgenic lines. Our findings provide new perspectives on the growth regulation mechanisms of PGIP proteins in plant cell walls and provide a potential candidate gene for breeding increased disease-resistance and higher cellulose production in plants.

Implications of bacteria‒bacteria interactions within the plant microbiota for plant health and productivity.

Crop production currently relies on the widespread use of agrochemicals to ensure food security. This practice is considered unsustainable, yet has no viable alternative at present. The plant microbiota can fulfil various functions for its host, some of which could be the basis for developing sustainable protection and fertilization strategies for plants without relying on chemicals. To harness such functions, a detailed understanding of plant‒microbe and microbe‒microbe interactions is necessary. Among interactions within the plant microbiota, those between bacteria are the most common ones; they are not only of ecological importance but also essential for maintaining the health and productivity of the host plants. This review focuses on recent literature in this field and highlights various consequences of bacteria‒bacteria interactions under different agricultural settings. In addition, the molecular and genetic backgrounds of bacteria that facilitate such interactions are emphasized. Representative examples of commonly found bacterial metabolites with bioactive properties, as well as their modes of action, are given. Integrating our understanding of various binary interactions into complex models that encompass the entire microbiota will benefit future developments in agriculture and beyond, which could be further facilitated by artificial intelligence-based technologies.

Application of Nanotechnology in Sericulture: A Review

Nanoparticles (NPs) have emerged as promising tools for enhancing mulberry cultivation and the performance of silkworms, crucial for silk production. Mulberry, a vital plant for silk production, demands proper nutrient management for optimal growth and leaf production. Application of NPs, particularly zinc oxide and iron oxide, has shown significant improvements in mulberry growth parameters. Furthermore, NPs have demonstrated positive effects on silkworm larvae, enhancing feed efficiency and growth parameters, leading to better cocoon traits. Silkworms fed with NPs-treated mulberry leaves exhibited increased body weight, cocoon weight, and silk filament characteristics. Additionally, NPs have shown promise in enhancing silkworm reproduction and fecundity while conferring resistance against diseases like BmNPV. Various NPs, including TiO2, silver and chitosan, have exhibited antibacterial properties against silkworm pathogens, thereby contributing to disease prevention. Overall, NPs offer a sustainable and effective approach to enhance mulberry cultivation, improve silkworm performance and mitigate disease risks, thus potentially revolutionizing silk production practices.

Differential responses of temperature sensitivity of greenhouse gases emission to seasonal variations in plateau riparian zones

Riparian zones, regarded as hotspots for greenhouse gas (GHG) emissions, where the variation in temperature sensitivity (Q10) of GHG emissions is crucial for assessing GHG budgets under global warming. However, the seasonal Q10 of GHG emissions from high-elevation riparian zones and underlying microbial mechanisms are poorly documented. This study focuses on seasonal Q10 patterns of GHG emissions from riparian zones along the Lhasa River on the Tibetan Plateau. CO2 and CH4 emissions from riparian soils were more sensitive to temperature in spring than in summer. The opposite trend was observed for Q10 of N2O emissions. Soil organic carbon (SOC) had relatively large direct effects on the Q10-CO2 value in summer, whereas soil nitrate nitrogen (SNO3−-N) was the determinant of Q10-CO2 value in spring. mcrA:pmoA and soil microbial biomass C (SMBC) had strong direct effects on the Q10 of CH4 emissions in summer; the Q10-CH4 value in spring was significantly affected by the mcrA abundance. SMBC and the nirK + nirS abundance were key factors affecting the Q10-N2O value. Q10-CO2 and Q10-CH4 values exhibited strong seasonalities in the lower reaches of riparian soils, mainly due to the seasonalities of SNO3−-N and mcrA:pmoA, respectively. The Q10-N2O value in the middle and upper reaches of riparian soils presented seasonality, which was largely due to the seasonalities of soil ammonia nitrogen and microbial biomass carbon. During thawing, plant productivity increased, substrate carbon was sufficient, microbial biomass increased, and inorganic nitorgen and denitrifier abundance decreased, causing 29.67% and 37.47% decreases in the Q10-CO2 and Q10-CH4 values, respectively, and a 70.85% increase in the Q10-N2O value, indicating that the potential release of N2O from riparian zones along the plateau river was more susceptible to seasonal variations. Our findings are conducive to accurately evaluating the potential contribution of GHG emissions from high-elevation riparian zones to global warming.

Salmonella Typhimurium caused an unprecedentedly large foodborne outbreak in Finland in 2021.

Salmonella infections are significant causes of foodborne outbreaks in the European Union. This study investigates a sudden increase in gastroenteritis patients in the hospital district of Central Finland in June 2021. The primary aim was to study the outbreak's magnitude and source of the outbreak. Epidemiological, microbiological, environmental and traceback investigations were conducted. Over 700 persons fell ill during the outbreak caused by Salmonella Typhimurium associated with a daycare lunch. Similar S. Typhimurium was found in the patients and a vegetable mix containing iceberg lettuce, cucumber and peas served during lunch. The traceback investigation revealed that the batch information of vegetables from the wholesaler was not complete. The wholesaler had received quality complaints about the iceberg lettuce from the central kitchen. The manufacturer did not test the suspected batch for Salmonella since the production plant had given a certificate declaring it Salmonella negative. The most suspect ingredient was one batch of iceberg lettuce due to quality complaints. The lettuce had not been served in two daycare centres without cases. We recommend that in order to enable thorough microbiological investigation, institutional kitchens store the food samples separately as part of the internal quality control and that food items should always be tested when Salmonella contamination in an outbreak is suspected.

Investigating sexual and asexual modes of reproduction in Palmer Amaranth (Amaranthus palmeri)

Abstract Palmer amaranth (Amaranthus palmeri S. Watson), a dioecious wind-pollinated plant, is one of the most troublesome crop weeds in the United States and is spreading northwards. The prodigious production of seed contributes to establishment of populations and spread across the landscape. Sexual reproduction via outcrossing is likely the primary mode of seed production for this dioecious plant. However, A. palmeri may also be capable of autonomous asexual seed production (apomixis), which could be beneficial during colonization. We conducted two studies of female isolation from pollen to investigate the propensity for autonomous seed production in 19 populations across eastern North America. In the first we observed low frequency seed production on many isolated females. Using flow cytometry of seed samples (FCSS) we primarily found patterns of ploidy consistent with sexual reproduction; no significant differences in ploidy between seeds produced on isolated females (putative apomicts) and non-isolated females (putatively sexual) were detected. We also investigated patterns of DNA content and found no evidence for polyploidy in 153 samples, which is often observed in apomictic species. The second female isolation trial utilized sex-specific molecular markers to identify and remove males prior to flowering, and we observed zero seed production. Overall, we did not detect evidence in support of apomixis in these populations of A. palmeri, suggesting that apomixis is unlikely to have played a role in the northward advance of this species in eastern North America. We also investigated whether there is variation between females and males in size and secondary reproductive traits. We found evidence for sexual dimorphism in three of six traits investigated: females are taller at senescence, produce longer secondary branches, and more axillary flowers than males. Differences in cost of reproduction and strategies for pollen release vs. pollen capture are likely factors shaping the evolution of sexual dimorphism in this wind-pollinated dioecious plant.

Mitigation of Karenia brevis Cells and Brevetoxins Using Curcumin, a Natural Supplement

Curcumin, a natural plant product, was investigated as a mitigation tool against Karenia brevis, the toxic dinoflagellate responsible for Florida red tides. A series of laboratory bench-top studies were conducted with additions of 0.1, 1, 2, 3, 5, 10, 20, 30, and 40 mg/L curcumin to K. brevis at an average of 1.0 × 106 cells/L to determine the efficacy of curcumin against K. brevis cells and brevetoxins and to optimize treatment dosage. Treatment with 5 mg/L of curcumin reduced K. brevis cell abundance by 89% and total brevetoxins by 60% within 24 h. Lower concentrations of curcumin (0.1–3 mg/L) exhibited between a 2 and 45% reduction in K. brevis and a reduction in brevetoxins of between 2 and 44% within 24 h. At the highest curcumin doses, 30 and 40 mg/L, a 100% reduction in cell abundance was observed by 6 h, with reduction in total brevetoxins by at least 64% in 48 h. These results suggest that curcumin, used alone or potentially in combination with other technologies, is a promising K. brevis bloom mitigation option.

Rapid and In-Field Sensing of Hydrogen Peroxide in Plant by Hydrogel Microneedle Patch.

The rapidly changing climate is exacerbating the environmental stress that negatively impacts crop health and yield. Timely sensing of plant response to stress is beneficial to timely adjust planting conditions, promoting the healthy growth of plants, and improving plant productivity. Hydrogen peroxide (H2O2) is an importantmolecule of signal transduction in plants. However, the common methods for detecting H2O2in plants are associated with certain drawbacks, such as long extraction time, cumbersome steps, dependence on large instruments, and difficulty in realizing in-field sensing. Therefore, it is urgent to establish more efficient detection methods to realize the rapid detection of H2O2 content in plants. In this research, poly (methyl vinyl ether-alt-maleic acid) (PMVE/MA) hydrogel microneedle (MN) patch for rapid extraction of leaf sap are prepared, and the extraction mechanism of PEG-crosslinked PMVE/MA hydrogel MN patch isstudied. A method of rapid detection of H2O2 content in plants based on MN patch with optical detection technology is constructed. The hydrogel MN patch can be usedfor timely H2O2 analysis. This application enables new opportunities in plant engineering, and can be extended to the safety and healthmonitoring of other plants and animals.

Industry 4.0 Solutions as Enablers for the Sustainability of the Italian Ceramic Tiles Sector

The Italian ceramic tiles district has a long tradition but is called to face new sustainability challenges related to the profitability, the environmental impact, and the capability to offer pleasant and motivating working conditions for new young employees. New Industry 4.0 approaches are emerging to evolve the current industrial organization and are expected to enhance the overall economic, environmental, and social viability. In this context, this paper aims at demonstrating the positive correlation between the new technologies and the sustainability of the sector. It outlines the main achievements of a 4-year project financed by the Italian government, involving the entire chain made up of research centers, technology providers, and tiles producers. The presented approach is concretized in several technological innovations based on the Industry 4.0 paradigm. Furthermore, a pilot line was created to test the new systems and collect data on the process. The main results are reported in terms of improved sustainability KPIs, such as extended possibility of control of production plants, waste reduction, lower consumption of raw materials and chemical additives. Finally, a sensible increase in the operators’ digitalization level is registered, making a shift from a physical and hard working environment towards more conceptual and attractive job conditions.

Fungal behavior and recent developments in biopulping technology.

Biological pretreatment of wood chips by fungi is a well-known approach prior to mechanical- or chemical pulp production. For this biological approach, a limited number of white-rot fungi with an ability to colonize and selectively degrade lignin are used to pretreat wood chips allowing the remaining cellulose to be processed for further applications. Biopulping is an environmentally friendly technology that can reduce the energy consumption of traditional pulping processes. Fungal pretreatment also reduces the pitch content in the wood chips and improves the pulp quality in terms of brightness, strength, and bleachability. The bleached biopulps are easier to refine compared to pulps produced by conventional methodology. In the last decades, biopulping has been scaled up with pilot trials towards industrial level, with optimization of several intermediate steps and improvement of economic feasibility. Nevertheless, fundamental knowledge on the biochemical mechanisms involved in biopulping is still lacking. Overall, biopulping technology has advanced rapidly during recent decades and pilot mill trials have been implemented. The use of fungi as pretreatment for pulp production is in line with modern circular economy strategies and can be implemented in existing production plants. In this review, we discuss some recent advances in biopulping technology, which can improve mechanical-, chemical-, and organosolv pulping processes along with their mechanisms.

Possible Factors of Poplar Susceptibility to Large Poplar Borer Infestation

Poplars (Populus spp.) are of significant ecological and economic importance. Long-term breeding efforts were aimed mainly at obtaining fast-growing and productive plants and less considered resistance to pests. This study aimed to identify patterns of susceptibility or resistance to Saperda carcharias (Linnaeus, 1758) (Coleoptera: Cerambycidae) infestation among clones of Populus hybrids and pure species, focusing on the influence of their placement, seasonal development, stem diameter, height increment, and crossing combinations. Among 34 clones of poplar species and hybrids of Ukrainian and foreign selection, in 2019–2023 S. carcharias infested 14 clones every year. Six clones (‘Ivantiivska’, ‘Kytaiska × pyramidalna’, ‘Volosystoplidna’, ‘Novoberlinska-3’, ‘Robusta’, and ‘Lada’) were the most susceptible to the infestation by S. carcharias. The clones of all presented poplar sections and their crossing combinations, except the Tacamahaca and Leucoides cross, were infested. Greater height increment promoted the infestation by S. carcharias. Ambiguous results were obtained regarding the susceptibility of Populus hybrids compared to pure species to S. carcharias infestations. Considering infestation by S. carcharias and plant placement in the site, it can be concluded that the clones ‘Sakrau45-51’, ‘Deltopodibna’, ‘Rosijska’, ‘Slava Ukrayiny’, ‘Lubenska’, ‘Rohanska’, and ‘Nocturne’ are resistant to this pest. Selecting native species clones or creating mixed clone plantations could enhance the resilience of poplar plantations to pest threats.

Digital model of hydraulic drive for solar tracker rotary control

An important area in the field of solar energy is considered, focusing on the use of a hydraulic drive in high-power solar trackers. In the context of the relevance of environmental problems and the commitment to energy efficiency, the role of solar trackers in increasing the productivity of solar power plants is investigated. An analysis of current trends in the field of hydraulic drive is presented, highlighting the prospects for its application. The analysis of the directions of improvement of the drives of the solar tracker is carried out. The hydraulic drive of the tracker is considered as an object of regulation. Disturbing loads of various types acting in the process of changing the position of the tracker are determined. The main load acting on the tracker drive is positional, caused by the gas–dynamic effect of the wind flow impinging on the tracker plane or the ambiguity of the behavior of the snow and ice cover. It is determined that the inertial load, when turning a high-power tracker, has a significant effect on the friction forces in the attachment points of the hinge support mechanisms. Options for the implementation of new circuit solutions for the tracker hydraulic drive are considered. Using information from sensors of movement of the rods of hydraulic motors of the tracker position drive, the sun position sensor, the control electronic module positions the solar tracker platform by supplying control signals to the electric hydraulic distributors of the drive. The hydromechanical regulators of the pump adjust the characteristics of the system to a random change in external loads on the tracker. A mathematical model of the hydraulic drive of the basic circuit tracker has been developed. The digital model of the tracker drive is designed to optimize the operation of the hydraulic drive, taking into account various factors such as inertia, viscous damping, hydraulic losses, system nonlinearities, thermal losses, elasticity of elements and the impact of external factors. The results obtained emphasize the efficiency and accuracy of the control system, making the hydraulic drive an important element in the development of clean and efficient energy.

Understanding the Molecular Mechanism of PGPR Strain Priestia megaterium from Tea Rhizosphere for Stress Alleviation and Crop Growth Enhancement

The study aimed to assess the plant growth-promoting (PGP) capabilities and abiotic stress tolerance of strain IHB B 7164 with a focus on identifying associated genes through genomic analysis. Isolated from the tea rhizosphere, strain underwent screening for multiple PGP traits and stress tolerance against various abiotic factors. Taxonogenomic analysis of the complete genome identified the bacterium as Priestia megaterium exhibiting high similarity (97.04 % ANI, 74.3 % in silico DDH) to P. megaterium ATCC 14581. Functional annotations of the genome highlighted gene clusters associated with PGP traits and stress tolerance substantiating the strain's potential in promoting plant growth under stress conditions. The strain demonstarted robust growth and PGP activities under stressed culture conditions such as acidity, temperature fluctuations, desiccation, salinity, and exposure to calcium, aluminum, and iron salts, affirming its status as a stress-tolerant rhizobacterium. Screening of PGP traits under acidic conditions revealed phosphate solubilization, ACC-deaminase activity and production of IAA-like auxins. Notably gluconic and oxalic acids were consistently detected during solubilization of tri-calcium phosphate (TCP), aluminum phosphate (Al-P), and iron phosphate (Fe-P). Inoculation with the strain led to significant enhancements in tea nursery plants including a 9 % increase in plant height, 10 % increase in leaf number, and substantial improvements in leaf fresh and dry weights. Similarly, pea and wheat yields recorded notable increases of 16.9 % and 18.3 %, respectively under field conditions. These findings underscore the efficacy of P. megaterium strain IHB B 7164 as an abiotic stress-tolerant and broad-spectrum plant growth promoting rhizobacteria (PGPR) capable of enhancing plant growth and productivity across diverse agricultural settings.

Carrabiitol®, a Novel Oligosaccharide Polyol Composition, Mitigates the Impact of Flooding, Drought, Salinity, and High Temperature in Tomato.

Abiotic stress results in various physiological and biochemical changes in plants. Osmolytes play a pivotal role in improving the tolerance to abiotic stress in plants. This study evaluated the effectiveness of a commercial formulation, Carrabiitol®, an oligosaccharide polyol composition, in alleviating adverse impacts of abiotic stress in tomato (Solanum lycopersicum L. var. Arka Rakshak) plants. Plants were raised from seed and treated with 1 mL/L, 2 mL/L, and 3 mL/L of Carrabiitol®. The foliage of developing plants was treated at the 2-3 leaf stage (T2, T3, and T4) and at pre-flowering stage (T5, T6, and T7). Growth conditions were compared with those of plants developed from untreated seed (T1). Developing tomato plants were then exposed to flooding, salinity (50 mM NaCl), high temperature (41.1 °C), or drought at the flowering stage. Plants were evaluated for their dry weight, leaf water potential, stomatal conductance, transpiration rate, antioxidant potential, chlorophyll, carotenoid, glucose, sucrose, malondialdehyde, and proline contents. Pre-treated seed, which received a booster treatment at the 2-3 leaf stage (T4 = seed treatment and booster at the 2-3 leaf stage with 3 mL/L Carrabiitol®) and pre-flowering stages (T5, T6, and T7 = seed treatment and booster doses at the pre-flowering stage with 1, 2, and 3 mL/L Carrabiitol®, respectively), was effective in mitigating negative impacts on various growth parameters of stressed tomato plants (p < 0.05). Carrabiitol® may be an effective, sustainable, and bio-rational organic osmolyte formulation for reducing the effects of abiotic stress on plant growth and productivity.

The Altai endemic &lt;i&gt;Sibiraea altaiensis&lt;/i&gt; (Laxm.) Schneid.: possible use and methods of conservation

The article provides a review of data on the Altai endemic Sibiraea altaiensis (Laxm.) Schneid., one of the archaic species of the genus Sibiraea Maxim. The species is included in the Red Books of the Altai Republic, the Altai Territory, and of Kazakhstan as a rare species, whose numbers are decreasing, mostly due to the influence of anthropogenic factors in its habitats. At the same time, S. altaiensis belongs to agriculturally important species, which is valued for its decorative, medicinal and other useful properties. The species is reproduced by seed, layering shoots, root and summer stem cuttings; however, these methods do not always give good results, and also require large areas for growing plants and are confined to a certain season of the year.Microclonal propagation of plants can become a promising method for the propagation and conservation of S. altaiensis. It consists in the use of in vitro techniques of rapid asexual production of plants that are genetically identical to the original specimen, with a significant saving of time and space required for growing planting material. The use of microcloning for the conservation and reproduction of rare and endangered species is highly justified, since it allows a significant increase in the reproduction rate of plant species, which are difficult or impossible to reproduce vegetatively, or those with low viability or seed productivity.Using in vitro protocols for the propagation of S. altaiensis, 10-28 microshoots were obtained from one lateral bud, which was used as an explant, when cultivated on a modified and a classic Murashige and Skoog (MS) nutrient media supplemented with 1.0 mgL-1 6-benzylaminopurine (6-BAP). These works confirm that in vitro cloning ensures a high reproduction rate of S. altaiensis and, thus, makes it possible to preserve the gene pool of the species and obtain planting material on a commercial scale without causing damage to natural populations.

Practical Guidelines for Farm Waste Utilization in Sustainable Kale Production

Natural amendments from agricultural waste to improve soil physicochemical properties continuously attract research interest in promoting eco-friendly plant production. The present study evaluated the proper use of sawdust, biochar, and compost made from farm waste for kale production from seedling propagation to field conditions. From the seedling propagation process, the results demonstrate that the most suitable growing medium for kale seedings was 0.5:1:1 v/v of sawdust + biochar + compost, which gave the fastest mean germination times (2.71 days) and the highest seed germination percentage (78.33%). In addition to investigating the selected growing media as the soil amendments at five different rates (0, 6.25, 12.50, 18.75, 25.00, and 31.25 t ha−1), the result reveals that the fresh weight of marketable leaves was significantly highest under the 31.25 t ha−1 treatment. The application rate that yielded the highest gross profit margins was eight times higher than the control. Moreover, in some harvesting periods, the kale leaf yields under the treatment of 31.25 t ha−1 showed higher total chlorophyll and carotenoid contents.

Sources of fertilizers on the phytotechnical characteristics, oxidative stress and thymol production of Thymus vulgaris L.

The objective of this study was to assess the effects of different fertilizer sources on the phytotechnical characteristics, oxidative stress, and thymol production of Thymus vulgaris. The experiment was conducted in 3-dm³ pots containing soil:sand (2:1) + treatment (no fertilizer, organic fertilizer, or chemical fertilizer). The organic fertilizer was 8 kg m-2 of an equal mixture of bovine, goat, and quail manures. The variables assessed were leaf, stem, root, and total dry weights; chlorophyll and carotenoid contents; leaf nutrients; total polyphenols; total antioxidant capacity; oxygen radical absorption capacity; DPPH free radical scavenging activity; essential oil content; and thymol production, content, and yield. Organic fertilization significantly increased the variables assessed and reduced oxidative stress indicators. It resulted in gains in the dry weight of the plants and the accumulation of nutrients in dry leaves of T. vulgaris. For the quantitative parameters of the essential oil and thymol, organic fertilization was significantly higher than the other treatments, especially for thymol content and yield. T. vulgaris plants fertilized with organic fertilizer maximize their plant production and their yield of compounds of interest, such as thymol, possibly because these outputs indicate a balance between improved vegetative production and the elimination of reactive oxygen species.

Insight into physico-chemical properties and microbial community structure of biogas slurry from household biogas plants of sub-Himalaya for its implications in improved biogas production.

Numerous metagenomics studies, conducted in both full-scale anaerobic digesters and household biogas plants, have shed light on the composition and activity of microbial flora essential for optimizing the performance of biogas reactors, underscoring the significance of microbial community composition in biogas plant efficiency. Although the efficiency of household biogas plants in the sub-Himalayan region has been reported, there is no literature evidence on the microbial community structure of such household biogas plants in the sub-Himalayan region. The current study evaluated the physico-chemical properties and bacterial community structure from the slurry samples of household biogas plants prevalent in the sub-Himalayan region. The slurry samples were observed to be rich in nutrients; however, their carbon and nitrogen contents were higher than the recommended standard values of liquid-fermented organic manure. The species richness and diversity indices (Chao1, Shannon, and Simpson) of household biogas plants were quite similar to the advanced biogas reactors operating at mesophilic conditions. 16S rRNA gene amplicon sequencing reveals microbial diversity, showing a higher abundance of Firmicutes (70.9%) and Euryarchaeota (9.52%) in advanced biogas reactors compared to household biogas plants. Microbial analysis shows a lack of beneficial microbes for anaerobic digestion, which might be the reason for inefficient biogas production in household biogas plants of the sub-Himalayan region. The lack of efficient bacterial biomass may also be attributed to the digester design, feedstock, and ambient temperatures. This study emphasized the establishment of efficient microbial consortia for enhanced degradation rates that may increase the methane yield in biogas plants.

Analysis of yellow mealworm (Tenebrio molitor) frass as a resource for a sustainable agriculture in the current context of insect farming industry growth

With the ongoing rapid growth of the human population, the industrial development of mass insect rearing for feed and food is gaining momentum. This approach has proved to be a more efficient and effective alternative to traditional livestock to produce animal protein. In this context, the Tenebrio molitor production sector emerges as highly promising in the edible insect market, being among the most commonly bred species in the large-scale insect rearing industry. A recent modification of the European regulatory framework in this matter has authorized insect-produced feed for pigs and poultry, which will boost the creation of new insect industries, resulting in huge quantities of frass, the insect excrement, that could be valorized. This by-product holds substantial amounts of nutrients and advantageous microorganisms that have enormous potential for organic farming. It typically exhibits high organic content and an abundance of essential nutrients like nitrogen (N), phosphorus (P), and potassium (K), alongside a narrow carbon (C) to nitrogen (N) ratio. In addition to providing plants with essential macronutrients, frass has been discovered to boost soil microbial biomass and introduce biomolecules and microbes that foster plant growth. The study of utilizing frass in sustainable agriculture is a relatively new and actively researched field in recent years. By conducting a comprehensive review of peer reviewed works, this article highlights the advantages associated with the effects of its use as organic fertilizer. Among these, the effect of frass as (1) a plant growth promoter and productivity enhancer and as (2) phytofortifyer against biotic and abiotic stresses, has been underlined in recent studies. With regard to its promoting effect, it has been observed that the effects of frass depend very much on its dose and the type of crop, with remarkably favorable results in many of the tests carried out. Hence, frass derived from the mass rearing of yellow mealworm for feed and food, could serve as an important and potent source of organic fertilizer in intensive horticultural crops or in high-value woody crops, contributing to a more sustainable agriculture, which can decrease the use of conventional synthetic agrochemicals.