Cyanobacterial Inoculation Research Articles

Cyanobacterial biocrust alters soil physical properties reducing soil erosion and aerosol production.

Aerosol emission by wind erosion in the arid and semi-arid areas of the world, is of environmental and health significance. Different methods have been used to mitigate aerosol emission among which the biological methods may be the most efficient ones. Although previously investigated, more research is essential to determine how the use of exopolysaccharide (biocrust)-producing cyanobacteria may affect soil physical properties. The objective was to investigate the effects of the cyanobacteria, Microcoleus vaginatus ATHK43 (identified and registered by the NCBI accession number MW433686), on soil physical properties of a sandy soil 15, 30, 60, and 90 d after inoculation. The effects of cyanobacterial biocrust on soil properties including shear strength, soil resistance, aggregate stability (mean weight diameter (MWD) and geometric mean diameter (GMD)), and wind erosion were determined in trays using a wind tunnel. Cyanobacterial inoculation significantly increased MWD (0-1cm depth, from 0.12mm to 0.47mm) and GMD (from 0.3 to 0.5mm) after a period of 90 d. Biocrust production significantly decreased soil erosion from 55.7 kgm- 2 to 0.3 kgm- 2 (wind rate of 50 kmh- 1), and from 116.42 kgm- 2 to 0.6 kgm- 2 (wind rate of 90 kmh- 1) after 90 d. In conclusion, cyanobacterial biocrust can significantly improve soil physical properties in different parts of the world including the deserts, and reduce aerosol emission by mitigating the destructive effects of wind erosion on soil physical properties.

Co-development of biocrust and herbaceous plant communities in sandy areas after cyanobacterial inoculation

Co-development of biocrust and herbaceous plant communities in sandy areas after cyanobacterial inoculation

Growth enhancement, metabolic profile improvement, and DXR and TPS2 gene expression changes in Thymus vulgaris L. by cyanobacterial inoculation.

In recent decades cyanobacterial species have attracted research attention as potential sources of new biostimulants. In this study, the biostimulant effects of five cyanobacterial suspensions on the growth and essential oil composition of Thymus vulgaris L. were evaluated. The expression of key genes involved in the biosynthesis of thymol and carvacrol, such as DXR and TPS2, were investigated. A pot culture experiment revealed that cyanobacterial application significantly improved T. vulgaris L. growth indices, including plant height, dry and fresh weight, leaf and flower number, leaf area, and photosynthetic pigment content. Total phenol and flavonoid content in inoculated plants also showed a significant increase compared with the control. Anabaena torulosa ISB213 inoculation significantly increased root and shoot biomass by about 65.38% and 92.98% compared with the control, respectively. Nostoc calcicola ISB215 inoculation resulted in the highest amount of essential oil accumulation (18.08 ± 0.62) in T. vulgaris leaves, by about 72.19% compared with the control (10.5 ± 0.50%). Interestingly, the amount of limonene in the Nostoc ellipsosporum ISB217 treatment (1.67%) increased significantly compared with the control and other treatments. The highest expression rates of DXR and TPS2 genes were observed in the treatment of N. ellipsosporum ISB217, with 5.92-fold and 5.22-fold increases over the control, respectively. This research revealed the potential of the cyanobacteria that were studied as promising biostimulants to increase the production of biomass and secondary metabolites of T. vulgaris L., which could be a suitable alternative to chemical fertilizers. © 2024 Society of Chemical Industry.

Interactions between Cyanobacteria and Methane Processing Microbes Mitigate Methane Emissions from Rice Soils.

Cyanobacteria play a relevant role in rice soils due to their contribution to soil fertility through nitrogen (N2) fixation and as a promising strategy to mitigate methane (CH4) emissions from these systems. However, information is still limited regarding the mechanisms of cyanobacterial modulation of CH4 cycling in rice soils. Here, we focused on the response of methane cycling microbial communities to inoculation with cyanobacteria in rice soils. We performed a microcosm study comprising rice soil inoculated with either of two cyanobacterial isolates (Calothrix sp. and Nostoc sp.) obtained from a rice paddy. Our results demonstrate that cyanobacterial inoculation reduced CH4 emissions by 20 times. Yet, the effect on CH4 cycling microbes differed for the cyanobacterial strains. Type Ia methanotrophs were stimulated by Calothrix sp. in the surface layer, while Nostoc sp. had the opposite effect. The overall pmoA transcripts of Type Ib methanotrophs were stimulated by Nostoc. Methanogens were not affected in the surface layer, while their abundance was reduced in the sub surface layer by the presence of Nostoc sp. Our results indicate that mitigation of methane emission from rice soils based on cyanobacterial inoculants depends on the proper pairing of cyanobacteria-methanotrophs and their respective traits.

Erratum to “Rapid artificial biocrust development by cyanobacterial inoculation and clay amendment”

Erratum to “Rapid artificial biocrust development by cyanobacterial inoculation and clay amendment”

Elevated CO2 along with inoculation of cyanobacterial biofilm or its partners differentially modulates C–N metabolism and quality of tomato beneficially

Diazotrophic cyanobacteria are known to influence nutrient availability in soil, however, their benefits under elevated CO2 environment, particularly on fruit quality attributes, is a less investigated aspect. Laboratory developed cyanobacterium-fungal biofilm (An-Tr), composed of Anabaena torulosa (An) as the matrix with the partner as Trichoderma viride (Tr), along with the individual partners were evaluated under ambient (aCO2-400 ± 50 ppm) and elevated (eCO2-700 ± 50 ppm) conditions, with and without tomato plants. An-Tr inoculation exhibited distinct and significantly higher values for most of the soil microbiological parameters, plant growth attributes and antioxidant/defense enzyme activities measured at 30 and 60 DAI (days after inoculation). Significant enhancement in soil nutrient availability, leaf chlorophyll, with 45–50% increase in the enzyme activities related to carbon and nitrogen assimilation, higher yields and better-quality parameters of tomato, with An-Tr biofilm or An inoculation, were recorded, particularly under eCO2 conditions. The fruits from An-Tr treatments under eCO2 exhibited a higher titrable acidity, along with more ascorbic acid, carotenoids and lycopene content, highlighting the superiority of this inoculant. Multivariate analyses revealed significant (p ≤ 0.05) interactions among cultures, DAI, and CO2 levels, illustrating that cyanobacterial inoculation can be advocated as a strategy to gainfully sequester eCO2. Significant improvement in yield and fruit quality along with 50% N savings, further attest to the promise of cyanobacterial inoculants for tomato crop in the climate change scenario.

Improvement in Mine Tailings Biophysicochemical Properties by Means of Cyanobacterial Inoculation

Improvement in Mine Tailings Biophysicochemical Properties by Means of Cyanobacterial Inoculation

Rapid artificial biocrust development by cyanobacterial inoculation and clay amendment

AbstractThe establishment of biological soil crusts is widely perceived as a main strategy to improve the ecological environment in arid and semi‐arid regions. However, artificial biocrusts fail to withstand environmental stresses when using traditional methods for initial establishment. Hence, in this study, kaolin, a common clay mineral, was introduced as a biocrust stabilizer by mixing at different mass ratios with Microcoleus steenstrupii for sand inoculation. The results showed that the addition of kaolin exhibited a significantly positive effect on promoting biocrust formation and accelerating biocrust development. Moreover, the artificial biocrust from 1:500 (algae: kaolin) inoculant achieved the best performance with coverage of 98%, and top layer thickness of 5.62 mm after 86 days of incubation. The highest contents of chlorophyll a, exopolysaccharides, and soluble protein were also observed in 1:500 mass ratio of algae: kaolin throughout the biocrust development process. As for the water retention performance, the results of contact angle, water drop penetration time (WDPT), and repellency index (RI) illustrated that biocrust improved water utilization in kaolin‐treated groups by delaying the time of water infiltration, especially in 1:500 group. After 86 days post inoculation, a series of common bacteria appeared in the biocrusts such as actinobacteria and acidobacteria, and decomposed metabolites from cyanobacteria as an energy source. This study gains new insights into clay minerals on biocrust development and puts forward a new approach for rapid artificial biocrust establishment to reverse desertification.

Plasma Treatment as a Sustainable Method for Enhancing the Wettability of Jute Fabrics

In this paper, raw jute fabric was subjected to atmospheric pressure dielectric barrier discharge (at 150 or 300 Hz) to enhance its wettability, i.e., capillarity and wetting time. Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and Field Emission Scanning Electron Microscopy (FE-SEM) were used to assess the changes in the fabrics’ surface chemistry and morphology induced by plasma treatments. The obtained results revealed that both plasma treatments enhanced the wettability of jute fabrics, which could be ascribed to the changes in the fibers’ surface chemistry (the removal of non-cellulosic components, exposure of the cellulose molecules, and oxidation) and morphology (increased roughness due to etching of the surface layers and partial fibrillation). Capillary rise heights increased by approximately 1.8 and 1.9 times, and wetting times were 35 and 34 times shorter 24 h after the plasma treatment at 150 and 300 Hz, respectively. Special attention was given to the aging effect of plasma treatment indicated no significant changes in the fabrics’ capillarity and wetting time after 28 and 7 days, respectively, proving the durability of the effects of plasma treatment. Plasma-treated raw jute fabrics could be used as water-binding geo-prebiotic polysaccharide supports to provide the necessary water for the initial growth of cyanobacterial biocrusts. The lack of moisture is the main constraint in biocrust development after cyanobacterial inoculation. The combination of such water-supportive fabrics and cyanobacterial strains could be used for the rehabilitation of various degraded lands, sediments, and substrates, as well as for air and water pollution control.

Coupling Sewage Sludge Amendment with Cyanobacterial Inoculation to Enhance Stability and Carbon Gain in Dryland Degraded Soils

Sewage sludge (SS) is widely used as a soil conditioner in agricultural soil due to its high content of organic matter and nutrients. In addition, inoculants based on soil microorganisms, such as cyanobacteria, are being applied successfully in soil restoration to improve soil stability and fertility in agriculture. However, the combination of SS and cyanobacteria inoculation is an unexplored application that may be highly beneficial to soil. In this outdoor experiment, we studied the ability of cyanobacteria inoculum to grow on degraded soil amended with different concentrations of composted SS, and examined the effects of both SS concentration and cyanobacteria application on carbon gain and soil stability. We also explored the feasibility of using cyanobacteria for immobilizing salts in SS-amended soil. Our results showed that cyanobacteria growth increased in the soil amended with the lowest SS concentration tested (5 t ha−1, on soil 2 cm deep), as shown by its higher chlorophyll a content and associated deeper spectral absorption peak at 680 nm. At higher SS concentrations, inoculum growth decreased, which was attributed to competition of the inoculated cyanobacteria with the native SS bacterial community. However, SS significantly enhanced soil organic carbon gain and tightly-bound exopolysaccharide content. Cyanobacteria inoculation significantly improved soil stability and reduced soil’s wind erodibility. Moreover, it led to a decrease in the lixiviate electrical conductivity of salt-contaminated soils, indicating its potential for salt immobilization and soil bioremediation. Therefore, cyanobacteria inoculation, along with adequately dosed SS surface application, is an efficient strategy for improving carbon gain and surface stability in dryland agricultural soil.

Influence of Cyanobacterial Inoculum on the Growth Features and Yield of Peanut Plants in Sandy Soil

Two field experiments were conducted at the Ismailia Agricultural Research Center Station during the summers of 2021 and 2022 to study the effects of cyanobacterial inoculation (Anabaena oryzae and Nostoc mascarum) on peanut plant growth, yield, and certain soil biological activities under different nitrogen fertilisation ratios and conditions. There are three applications: soil drenching, cyanobacterial seed coating, and foliar spray with cyanobacterial strains.The findings demonstrated that cyanobacteria inoculation of peanut plants generally improved peanut plant growth, resulting in significantly higher peanut and grain yields than uninoculated treatments. When compared to other tested treatments and types of applications, N. mascarum + 75% (N) produced the highest peanut yield and plant characteristics, followed by A. oryzae + 75% (N) in soil drench application. Overall, cyanobacteria increased the amount of N, P, K, and Ca in peanut plants. Cyanobacteria inoculation improved soil fertility by increasing total bacterial and cyanobacterial count (CO2) evolution, and indole acetic acid contents in the peanut rhizosphere. In general, peanut growth in sandy soil conditions can benefit from cyanobacteria inoculation with 75% nitrogen amounts.

Impact of Cyanobacterial Inoculant on Growth and Productivity of Peanut Plants in Sandy Soil

During the summer growing seasons of 2021 and 2022, two field experiments were conducted at Ismailia Agricultural Research Center Station(Latitude 30ᵒ 35′ 41.901″ N and Longitude 32ᵒ 16′ 45. 843″E) to study the effect of cyanobacterial inoculation (Anabaena oryzae (A. oryzae) and Nostoc mascarum (N. mascarum)) on peanut yield, quality and certain soil biological activities under various nitrogen fertilization conditions and three types of applications, thefirst treatment was carried out as coating seeds with powder of individual of each cyanobacterial strain and the before planted, second treatment seeds were drenched withsuspension of eachcyanobacterial strain individually andthe last treatment was by foliar doses after 15, 45 and 60 days from seeds planting. Results showed that applying cyanobacteria inoculation to peanut plants generally enhanced peanut plant growth, leading to significantly higher yields of peanut and grains than uninoculated treatments. Treatment of N. mascarum + 75% N recorded the highest peanut yield and plant characteristics followed by N. mascarum+ 75% N in soil drench application compared to other tested treatments and types of applications. Cyanobacteria enhanced the amount of N, P, Kand Ca in peanut plants overall. By increasing the total chlorophyl, carotenoids, dehydrogenase, urease activities and nutrients in the peanut rhizosphere, cyanobacteria inoculation had a favorable impact on soil fertility. In general, cyanobacteria inoculation with 75% nitrogen amounts can benefit under peanut growth in sandy soil conditions.

Cyanobacterial Inoculation Enhances Nutrient Use Efficiency and Grain Quality of Basmati Rice in the System of Rice Intensification

Cyanobacterial Inoculation Enhances Nutrient Use Efficiency and Grain Quality of Basmati Rice in the System of Rice Intensification

Influence of cyanobacterial inoculants, elevated carbon dioxide, and temperature on plant and soil nitrogen in soybean.

Climate change affects nitrogen dynamics in crops and diazotrophic microorganisms with carbon dioxide (CO2 ) sequestering potential such as cyanobacteria can be promising options. The interactions of three cyanobacterial formulations (Anabaena laxa, Calothrix elenkinii and Anabaena torulosa-Bradyrhizobium japonicum biofilm) on plant and soil nitrogen in soybean, were investigated under elevated CO2 and temperature conditions. Soybean plants were grown inside Open Top Chambers under ambient and elevated (550 ± 25 ppm) CO2 concentrations and elevated temperature (+2.5-2.8°C). Interactive effect of elevated CO2 and cyanobacterial inoculation through A. laxa and Anabaena torulosa-B. japonicum biofilm led to improved growth, yield, nodulation, nitrogen fixation, and seed N in soybean crop. Nitrogenase activity in nodules increased in A. laxa and biofilm treatments, with an increase of 55% and 72%, respectively, over no cyanobacterial inoculation treatment. Although high temperature alone reduced soil microbial biomass carbon, dehydrogenase activity, and soil available N, the combined effect of CO2 and temperature were stimulatory; cyanobacterial inoculation further led to an increase under all the conditions. The highest seed N uptake (758 mg plant-1 ) was recorded with cyanobacterial biofilm inoculation under elevated CO2 with control temperature conditions. The positive interactions of elevated CO2 and cyanobacterial inoculation, particularly through A. laxa and A. torulosa-B. japonicum biofilm inoculation highlights their potential in counteracting the negative impact of changing climate along with enhancing plant and soil N in soybean.

Cyanobacterial inoculation in elevated CO2 environment stimulates soil C enrichment and plant growth of tomato

The present study investigated the influence of cyanobacterial inoculants viz., Anabaena laxa (A.laxa) ), Calothrix elenkinii (C. elenkinii) and Anabaena torulosa- Trichoderma viride (An-Tr) under ambient (aCO2) and elevated (eCO2) conditions, on soil and plant parameters, when grown with/without tomato crop. Significant enhancement in soil chlorophyll, proteins, polysaccharide content, total leaf pigments and C-N assimilating enzyme activities was recorded under elevated CO2 conditions with cyanobacterial inoculation, when grown with/without tomato crop. Supplementation with A. laxa led to more than a fold-enhancement in polysaccharides and 40%–45% increment in available nitrogen, while An-Tr recorded 60%–70% increase in soil microbial biomass carbon under elevated CO2 condition. A. laxa treatment also recorded highest plant pigments, glutamine synthetase and carbonic anhydrase activity under elevated CO2 condition. Distinct influence of elevated CO2 condition, cyanobacterial inoculation and plant and their interactions were recorded. Interestingly, plants grown under elevated CO2 showed early flowering, by eight days, compared to ambient conditions. Phospholipid fatty acid profiles of soil samples illustrated significant changes in the total biomass and distribution of notional microbial groups due to inoculation and the presence of plant. Multivariate analyses illustrated the significant interactions among the soil and microbiological attributes, highlighting that cyanobacterial inoculation can be a promising intervention to utilize beneficially the elevated CO2 for enhancing soil nutrients, crop growth and productivity in tomato.

Salinity affects microbial composition and function in artificially induced biocrusts: Implications for cyanobacterial inoculation in saline soils

Cyanobacterial inoculation is a promising technology that can induce biocrust development, for stabilizing degraded soils in dryland environments. However, it is challenging to grow cyanobacteria in dry, saline soils, which limits the application of this technology. In this study, NaCl was added into field-collected induced biocrusts to investigate how salt affects the biocrust community. This fundamental knowledge improves our assessment of microbial salinity preference and adaptation, and can guide researchers to select the appropriate cyanobacterial inoculants for saline soil restoration. The results showed that the biocrusts induced by inoculating Microcoleus vaginatus and Scytonema javanicum could survive 1.0% salinity, although both salt and drought stresses significantly inhibited microbial biomass and metabolism (P < 0.05), and salinity led to an obvious shift in microbial community structure. Compared to salt stress, drought seems to provide a vital ecological protection for the biocrusts, allowing them to be active only under relative low salinity after hydration. In the induced biocrusts, cyanobacteria were always the dominant organisms (even 18 years since inoculation), whereas under elevated salinity, cyanobacterial communities with lower relative abundance had a higher survival percentage of M. steenstrupii and Phormidium sp. Altogether, our results showed that both prokaryotic and eukaryotic communities have obvious salinity preference in the cyanobacteria-induced biocrusts. These results suggest that cyanobacterial inoculation strategies can be adapted in response to the soil salinity conditions. Furthermore, a combined inoculation of M. steenstrupii and Phormidium sp. appears to be favorable approach that is expected to improve cyanobacterial inoculation technology in saline soils.

Physical Disturbance Reduces Cyanobacterial Relative Abundance and Substrate Metabolism Potential of Biological Soil Crusts on a Gold Mine Tailing of Central China.

As the critical ecological engineers, biological soil crusts (biocrusts) are considered to play essential roles in improving substrate conditions during ecological rehabilitation processes. Physical disturbance, however, often leads to the degradation of biocrusts, and it remains unclear how the physical disturbance affects biocrust microorganisms and their related metabolism. In this study, the photosynthetic biomass (indicated by chlorophyll a), nutrients, enzyme activities, and bacterial communities of biocrusts were investigated in a gold mine tailing of Central China to evaluate the impact of physical disturbance on biocrusts during the rehabilitation process of gold mine tailings. The results show that physical disturbance significantly reduced the photosynthetic biomass, nutrient contents (organic carbon, ammonium nitrogen, nitrate nitrogen, and total phosphorus), and enzyme activities (β-glucosidase, sucrase, nitrogenase, neutral phosphatase, and urease) of biocrusts in the mine tailings. Furthermore, 16S rDNA sequencing showed that physical disturbance strongly changed the composition, structure, and interactions of the bacterial community, leading to a shift from a cyanobacteria dominated community to a heterotrophic bacteria (proteobacteria, actinobacteria, and acidobacteria) dominated community and a more complex bacterial network (higher complexity, nodes, and edges). Altogether, our results show that the biocrusts dominated by cyanobacteria could also develop in the tailings of humid region, and the dominants (e.g., Microcoleus) were the same as those from dryland biocrusts; nevertheless, physical disturbance significantly reduced cyanobacterial relative abundance in biocrusts. Based on our findings, we propose the future work on cyanobacterial inoculation (e.g., Microcoleus), which is expected to promote substrate metabolism and accumulation, ultimately accelerating the development of biocrusts and the subsequent ecological restoration of tailings.

Cyanobacterial persistence and influence on microbial community dynamics over 15 years in induced biocrusts.

Biocrusts provide numerous ecological functions in drylands. Recovering biocrusts via cyanobacterial inoculation recently gathered interest for ecological restoration, yet it still lacks long-term experiments to unravel biocrust community dynamics. To examine how cyanobacterial inoculants influenced local microbial community and biocrust development, we observed a 2 km2 (Qubqi Desert, China) inoculation experiment after 10 and 15 years, following biocrust formation. Our results revealed that biocrust development was in line with ecological regime shift, providing evidence for biocrust community succession, from cyanobacteria- to moss-dominated types. Associated with biocrust development, microbial communities differed significantly with less specialists compared to shifting sands. Cyanobacterial community analysis showed that Microcoleus vaginatus and Scytonema javanicum are an ideal inoculating model, as they were still dominating the community after 15 years since inoculation, while other nitrogen-fixing cyanobacteria occurred profusely with biocrust development. Biocrust community composition combined with thickness, Chl-a and exopolysaccharide measurements revealed the large variation of cyanobacterial ecological functions along biocrust development, suggesting a main function shift: from carbon fixation associated with exopolysaccharide secretion in bare sandy soils to nitrogen fixation in developed biocrusts. This large-scale field study verifies that cyanobacterial inoculation accelerates biocrust development and forwards succession, shaping the biocrust community composition over a long time.

Biocrust cyanobacteria inoculants biomineralize gypsum and preserve indigenous bacterial communities in dryland topsoil

Biocrust cyanobacteria are ubiquitous organisms in dryland environments that can enhance soil stability and improve nutrient conditions in reconstructed or disturbed soils. Despite the demonstrated benefits of cyanobacterial inoculation for promoting soil fertility, there is limited knowledge about the impacts of introducing cultured cyanobacteria on the indigenous microbial communities. Here, we conducted a microcosm experiment under controlled conditions using indigenous biocrust cyanobacteria and locally sourced topsoil substrate commonly used in dryland restoration in the Australian arid zone. We inoculated the topsoil with a consortium composed of Leptolyngbya sp. and Scytonema sp. cyanobacteria, to assess the effects of the inoculated cyanobacteria on (i) the soil chemical properties, i.e., pH, electrical conductivity (EC), total organic carbon (TOC), and nitrogen (TN) of the inoculated topsoil, (ii) the early formation of an artificial soil biocrust and iii) the composition and diversity of the resident bacterial community. Our results showed that the inoculated cyanobacterial consortia decreased the EC, but changes in the TOC and TN were not significant after 80 days. A higher content of chlorophyll a in the inoculated samples compared to the control, confirmed the survival of the cyanobacterial inoculants after 80 days. The inoculated cyanobacteria promoted gypsum formation on the soil surface indicating that they are actively modifying the upper layers of the soil profile and improving habitability. Although immediately after inoculation cyanobacteria dominated the abundance of bacterial phylotypes, these were replaced by other phyla such as Actinobacteria, after 80 days. The Shannon diversity and Simpson diversity indexes between control and inoculated soils differed at the time of inoculation but were similar at the end of the experiment. These results suggest that, in the short term, the introduced cyanobacteria do not significantly affect the native resident bacterial communities and are capable of colonizing the topsoil without affecting the natural community.

Unprecedented biodesalination rates–Shortcomings of electrical conductivity measurements in determining salt removal by algae and cyanobacteria

Phormidium keutzingianum performed biodesalination of brackish water (10 g/L). The electrical conductivity (EC) was measured to evaluate the salt concentration over 80 days of cyanobacterial inoculation. Anion concentrations were measured using ion chromatography to estimate salt removal. EC-based measurements showed ∼8–10% removal efficiency in the first 20 days. However, the removal efficiency based on chloride ion concentration showed ∼40% removal in the same time frame. The pH increase was observed with growth of algal biomass. The increasing pH proposes the formation of hydroxyl and carbonate ions. Sulfuric acid was added at day 110 to neutralize them. At pH 4, the EC reduced significantly to about ∼37% confirming the chloride removal. EC should not be used to measure salt reduction as it is an obscure parameter, and therefore, EC is not the best choice to measure salinity removal using algae. Some recently published studies used only EC to estimate biodesalination, and it is anticipated that salt removal is misrepresented in those studies.