Improved Biomass Production Research Articles

Mixotrophy in Marine Microalgae to Enhance Their Bioactivity

Photosynthetic microorganisms, such as microalgae, are remarkable for their ability to harness sunlight, fix carbon dioxide, and produce a variety of bioactive compounds. These organisms are pivotal in climate mitigation strategies as they can absorb carbon dioxide while generating valuable biomolecules. Among the diverse cultivation approaches, mixotrophic growth combines light energy with both inorganic and organic carbon sources, offering a unique strategy to enhance biomass production and metabolic diversity in microalgae. Here, microalgal species such as Nannochloropsis granulata, Phaeodactylum tricornutum, and Chlorella sp. were investigated for their potential applications under different cultivation methods, including phototrophy and mixotrophy. Mixotrophic conditions significantly improved biomass production across all tested species. Among these, Phaeodactylum tricornutum, a marine diatom, emerged as a promising candidate for bioactive compound production, exhibiting higher antiproliferative activity against human melanoma cells and antibacterial effects against Staphylococcus aureus. Importantly, Chlorella sp. was also found to possess antibacterial activity against Staphylococcus aureus, broadening its potential applications. Additionally, metabolomics analysis was performed on Chlorella sp. and Phaeodactylum tricornutum to identify the compounds responsible for the observed bioactivity. This study highlights the value of mixotrophic cultivation in enhancing the productivity and bioactivity of microalgae, positioning them as versatile organisms for sustainable biotechnological applications.

Impact of short-term pasture development on soil aggregation, temperature sensitivity of soil organic carbon, and functional diversity in semi-arid ecosystem

Pasture development could be a viable option to restore degraded land in semi-arid region. New knowledge on soil functional diversity, aggregation, and temperature sensitivity (Q 10) of soil organic carbon (SOC) after pasture development would assist to accomplish the scope of global pastureland management for climate change mitigation and land restoration. To understand the impact of pasture development on soil aggregation, SOC stock, and its Q 10, research was undertaken at three development sites (RS1, RS2, RS3) in India with seeding of Cenchrus ciliaris, Megathyrus maximus, and Stylosanthes seabrana (at a line-ratio of 2:2:1). After three years, biomass productivity and for SOC, aggregation, enzyme activities, etc. at 0–20 and 21–40 cm depths were estimated. Pasture development improved biomass productivity from 0.68 mg ha−1 in undeveloped site to 3.62–4.64 mg ha−1. Pasture development enhanced SOC stock from 5.85 to 7.31 mg C ha−1 at the surface layer with an annual accumulation rate of 28–112 kg SOC ha−1 year−1. Greater activities of extracellular enzymes were observed at the surface soil layer in pasture development sites over undeveloped control. The mean weight diameter was ∼23–38% higher at pasture development sites over undeveloped sites. The Q 10 being controlled by the labile carbon was significantly higher (13–29%) at the pasture development sites over undeveloped site. Hence, short-term pasture development could improve the SOC stocks at the surface layer only, but the stocks were vulnerable to C loss at higher temperature. However, long-term pasture development could have a great potential to accrue C to mitigate climate change.

Towards sustainable spirulina farming: Enhancing productivity and biosafety with a salinity-biostimulants strategy.

Arthrospira platensis (spirulina) is pivotal to the global microalgae industry, valued for its nutritional and bioactive properties. However, its sustainable production is challenged by freshwater scarcity and biological contaminants. This study introduces a salinity-biostimulants strategy to adapt a freshwater spirulina strain, CBD05, to near-seawater salinity (3%). Exogenous glycine betaine (GB) and nitric oxide (NO), typical salinity enhancers, improved biomass productivity (0.36g L-1 d-1), C-phycocyanin (C-PC) yield (83mg L-1 d-1), and the economic output-to-input ratio was significantly enhanced. Metabolomic analysis linked salt tolerance to elevated amino acid accumulation, protein synthesis, and glycolysis, while transcriptional evidence highlighted enhanced carbon fixation and nitrogen assimilation towards C-PC synthesis upon addition of GB and NO. This strategy also demonstrated high resistance to Microcystis aeruginosa, a common contaminant in open systems. It provides a sustainable and cost-effective approach for industry-oriented spirulina production in freshwater-limited regions.

Effect of incident light and light gradients on eicosapentaenoic acid distribution between lipid classes in Nannochloropsis oceanica

AbstractCommercial production of eicosapentaenoic acid (EPA) from photoautotrophic microalgae like Nannochloropsis oceanica requires higher productivity and larger scales to reduce costs. Improving productivity can be achieved by increasing biomass concentrations, which creates light gradients in the reactor depending on the culture’s acclimation and the reactor geometry. These light gradients affect physiology, lipid synthesis, but also the distribution of fatty acids between lipid classes. In this study we evaluated the combined effect of the incident light intensity and light gradient on growth, biochemical composition, and fatty acid distribution between lipid classes. A total of 13 cultivations were performed in continuous mode using three different incident light intensities (200, 670, and 1550 μmol photons m−2 s−1) and four dilution rates (from 0.29 to 0.75 day−1). Reducing dilution rates resulted in higher biomass concentrations, steeper light gradients, and lower average light intensities. Increasing incident light intensity improved biomass productivity from 0.5 to 1.8 g L−1 day−1, while the biomass yield on light decreased from 1.05 to 0.44 g mol−1. Lowering average light intensities decreased the triglyceride content from 11.1 to 1.5% w/w, and increased the galactolipid content, mainly monogalactosyldiacylglycerol, up from 3.1 to 5.1% w/w. Total EPA contents did not decrease at low incident light but decreased by 28% at highly saturating light, both relative to medium incident light. The EPA content in polar lipids increased at lower average light intensities, and decreased in the neutral fraction simultaneously. These results highlight the tight regulation of EPA content between lipid polar and neutral fractions under different light regimes. Graphical Abstract

From coffee waste to nutritional gold: bioreactor cultivation of single‐cell protein from Candida sorboxylosa

AbstractBACKGROUNDIndustrial effluents are continuously discharged into the environment. These wastewaters contain valuable compounds that can be reused for biotechnological applications. Coffee wastewater (CWW) is a powerful effluent that can be used for single‐cell protein (SCP) production reaching important content (up to 80%). Several yeast species can be used for SCP production, but Candida species are commonly applied for this purpose (17 species reported including the novel C. sorboxylosa). In addition, SCP can be produced in bioreactors under controlled conditions under three operation modes. Thus, batch mode is frequently used but continuous mode presents interesting advantages in economic terms, although it has been poorly applied in SCP production.RESULTSThe initial evaluation under batch operation mode showed that volumetric oxygen transfer coefficient (kLa of 101 h−1) improved biomass production (1.39 g L−1) and SCP yield (59.9%) in C. sorboxylosa. Thus, continuous mode was established at selected kLa and feeding with optimized medium composed of 87.5% (v/v) CWW, 1.38 g L−1 yeast extract, and 7.24 g L−1 (NH4)2SO4, in order to provided necessary nutrients. In this sense, the process presented higher values in dry cell weight and SCP productivity (0.57 and 0.29 g L−1·h, respectively), achieving a 3.35‐ and 2.90‐fold increase in biomass and protein productivity, respectively, compared to batch mode. The SCP from C. sorboxylosa exhibited an interesting essential amino acid profile under continuous mode (33.704%).CONCLUSIONThe bioprocess highlights several advantages during bioreactor cultivation, including: (i) reduced energy consumption for temperature control; (ii) successful establishment of an initial continuous operation mode with promising performance; and (iii) SCP from C. sorboxylosa exhibited a notable composition of essential amino acids, which could be beneficial for potential use in animal feed. © 2024 Society of Chemical Industry (SCI).

Towards maximizing biomass and lipid productivity: high-throughput screening assay for prospecting heterotrophic growth for new microalgal isolates

BackgroundMicroalgae have emerged as sustainable alternatives to fossil fuels and high-value petrochemicals. Despite the commercial potential of microalgae, their low biomass productivity is a significant limiting factor for large-scale production. In the photoautotrophic cultivation of microalgae, achievable cell density levels depend on the light transmittance of the production system, which can significantly decrease the photosynthetic rate and biomass production. In contrast, the mixotrophic cultivation of microalgae using heterotrophic carbon sources enables high-density cultivation, which significantly enhances biomass productivity. The identification of optimal production conditions is crucial for improving biomass productivity; however, it is typically time- and resource-consuming. To overcome this problem, high-throughput screening (HTS) system presents a practical approach to maximize biomass and lipid production and enhance the industrial applicability of microalgae.ResultsIn this study, we proposed a two-step HTS assay that allows effective screening of heterotrophic conditions compatible with new microalgal isolates. To confirm the effectiveness of the HTS assay, three microalgal isolates with distinctive morphological and genetic traits were selected. Suitable cultivation conditions, including various heterotrophic carbon sources, substrate concentrations, and temperatures, were investigated using a two-step HTS assay. The optimized conditions were validated at the flask scale, which confirmed a significant enhancement in the biomass and lipid productivity of each isolate. Moreover, the two-step HTS assay notably enhanced economic and temporal efficiency compared to conventional flask-based optimization.ConclusionsThese results suggest that our two-step HTS assay is an efficient strategy for investigating and optimizing microalgal culture conditions to maximize biomass and lipid productivity. This approach has the potential to enhance the industrial applicability of microalgae and facilitate the seamless transition from laboratory to field applications.

Piggery wastewater treatment by solar photo-Fenton coupled with microalgae production

Pig farming generates highly polluted wastewater that requires effective treatment to minimize environmental damage. Microalgae can recover nutrients from piggery wastewater (PWW), but excessive nutrient and turbidity levels inhibit their growth. Solar photo-Fenton (PF) offer a sustainable and cost-effective pretreatment to allow microalgal growth for further PWW treatment. This study optimized the concentrations of PF reagents to minimise water and nutrient inputs while maintaining microalgae-based treatment efficiency. PF trials were conducted in pilot-scale raceway ponds under solar radiation, testing different concentrations of FeSO4 (4.48 and 8.95 mM) and H2O2 (77, 154, and 309 mM). Following PF, Tetradesmus obliquus was used in a biological treatment of PWW to recover the remaining nutrients. PF achieved high removal efficiencies for turbidity (97.6-99.5%), total organic carbon (59.2-77.1%), and chemical oxygen demand (83.8-94.7%), but ammonium was not significantly removed. Phosphorus was almost completely removed through iron precipitation during neutralisation. Lowering the H2O2 concentration from 309 to 77 mM did not compromise removal efficiency but reducing FeSO4 below 8.95 mM negatively affected the process. Consequently, 8.95 mM FeSO4 and 77 mM H2O2 were selected for microalgae production. The pretreated PWW could be recycled at least once for microalgal production, without nutrient supplementation, improving biomass productivity and PWW treatment, especially targeting ammonium. Phosphorus supplementation, however, did not significantly boost biomass productivity or treatment efficiency. Moreover, the iron sludge generated from PF pretreatment contained enough NPK to be repurposed as an organic fertilizer boosting sustainable agricultural practices. These findings encourage further investigation of this emerging combined technology towards wastewater treatment at large-scale.

Stress reduction with co-culture of Miscanthus x giganteus and Pelargonium x hortorum in a pb contaminated soil to improve biomass production

The industrial past of most regions in Lorraine and the intensification of activities on soils has increased the number of polluted sites. To rehabilitate these areas, several methods can be employed. In this study, co-culture of Miscanthus x giganteus and Pelargonium x hortorum was used to clean up a soil mainly contaminated by metallic elements including lead. The use of ornamental plants has been little studied, even if these species can be used to rehabilitate a site while improving its esthetics. At the end of the experiment, Pb concentrations were measured in the soil and plants. Furthermore, phytohormones were also measured to evaluate the defense mechanisms of the plants in front of pollutants. The results showed a reduction in Pb concentrations following the phytoremediation process implemented and that PxH was able to extract Pb from the soil. Results showed that co-culture was not beneficial to the development of MxG. Concerning the molecules synthesized by the plants under stress conditions, only salicin was found in MxG roots and aerial parts in particular for plants grown in individual culture. According to the results obtained, it seems that MxG is able to make compromises between the synthesis of protective molecules and its development.

Behaviour of ionic herbicides in different forestry soils derived from volcanic ash

Background: Weed control has been one of the most significant factors in forest establishment practices that can improve biomass production, and herbicides represent the most effective and convenient way to control weeds. The environmental concern about herbicides in this industry is because the herbicide-treated area is often located near water reservoirs or areas where rivers and creeks originate. This study aimed to determine the adsorption and degradation behaviours of seven ionic herbicides used in forestry production in five Chilean forestry soils and their relation to the leaching and to generate information to validate environmental predictive models. Methods: Adsorption and degradation of ionisable herbicides such as simazine, terbuthylazine, hexazinone, metsulfuron-methyl, indaziflam, flazasulfuron and glyphosate were studied in Andisol, Ultisol, Inceptisol, Entisol and Alfisol forestry soils, to be related to their leaching in 100-cm high and 11-cm diameter soil disturbed lysimeters. Herbicides were quantified using high-pressure liquid chromatography and gas chromatography. Relationships between soil physicochemical properties, herbicide adsorption and degradation, and herbicide leaching were determined. Results: In decreasing order, the herbicides were mobile in Entisol>Alfisol>Ultisol>Inceptisol>Andisol soils. On the other hand, the more leachable herbicides, from high to low, were: hexazinone, metsulfuron-methyl, simazine, glyphosate, terbuthylazine, flazasulfuron and indaziflam. The last two herbicides were not detected below 60 cm soil depth. In general, the maximum soil depth herbicide reached and the percentage mass leached up to 90 cm soil depth were inversely related to soil adsorption (1/Kd), soil porosity, humidity, silt, aluminium, and calcium soil content. Herbicide degradations were generally faster than referential published values. Conclusions: The environmental coefficients of ionic herbicides were more related to soil properties than their physicochemical properties. Persistence of herbicides in soil was smaller than that commonly reported in other studies or international databases and soil adsorption averages were generally higher than international reference values. The stronger relationship between ionic herbicide behaviour and forestry soil properties endorses the requirement to determine the environmental herbicides parameters in situ, avoiding using parameters estimated in other soils.

Overexpression of forage millet (Setaria italica) SiER genes enhances drought resistance of Arabidopsis thaliana.

ERECTA (ER) is a type of receptor-like kinase that contributes a crucial mission in various aspects of plant development, physiological metabolism, and abiotic stresses responses. This study aimed to explore the functional characteristics of the SiER family genes in millet (Setaria italica L.), focusing on the growth phenotype and drought resistance of Arabidopsis overexpressed SiER4_X1 and SiER1_X4 genes (SiERs ). The results revealed that overexpression of SiER4_X1 and SiER1_X4 genes in Arabidopsis significantly enhanced the leaf number, expanded leaf length and width, further promoted the silique number, length and diameter, and plant height and main stem thickness, ultimately leading to a substantial increase in individual plant biomass. Compared to the wild-type (WT), through simulated drought stress, the expression level of SiER genes was notably upregulated, transgenic Arabidopsis seeds exhibited stronger germination rates and root development; after experiencing drought conditions, the activities of antioxidant enzymes (superoxide dismutase and peroxidase) increased, while the levels of malondialdehyde and relative electrical conductivity decreased. These results indicate that overexpression of SiERs significantly enhanced both biomass production and drought resistance in Arabidopsis . The SiER4_X1 and SiER1_X4 genes emerge as promising candidate genes for improving biomass production and drought resistance in forage plants.

Carbonic anhydrase encapsulation using bamboo cellulose scaffolds for efficient CO2 capture and conversion

Utilizing carbonic anhydrase (CA) to catalyze CO2 hydration offers a sustainable and potent approach for carbon capture and utilization. To enhance CA's reusability and stability for successful industrial applications, enzyme immobilization is essential. In this study, delignified bamboo cellulose served as a renewable porous scaffold for immobilizing CA through oxidation-induced cellulose aldehydation followed by Schiff base linkage. The catalytic performance of the resulting immobilized CA was evaluated using both p-NPA hydrolysis and CO2 hydration models. Compared to free CA, immobilization onto the bamboo scaffold increased CA's optimal temperature and pH to approximately 45 °C and 9.0, respectively. Post-immobilization, CA activity demonstrated effective retention (>60 %), with larger scaffold sizes (i.e., 8 mm diameter and 5 mm height) positively impacting this aspect, even surpassing the activity of free CA. Furthermore, immobilized CA exhibited sustained reusability and high stability under thermal treatment and pH fluctuation, retaining >80 % activity even after 5 catalytic cycles. When introduced to microalgae culture, the immobilized CA improved biomass production by ∼16 %, accompanied by enhanced synthesis of essential biomolecules in microalgae. Collectively, the facile and green construction of immobilized CA onto bamboo cellulose block demonstrates great potential for the development of various CA-catalyzed CO2 conversion and utilization technologies.

The potential of bacterial endophytes on orchids

Orchids are one of the most exquisite and diverse plant species in nature. The seeds of orchids are non-endospermic and, therefore, dependent on endophytes for germination, growth, and adaptability. Orchids are prized for their beauty and therapeutic and culinary qualities by naturalists and the general public. Many orchid species are now endangered or vulnerable due to collectors' eagerness to take them. Current studies on orchids have concentrated on isolating and identifying the mycorrhizal and non-mycorrhizal endophytes that either directly or indirectly help orchids to grow, develop, and produce beneficial secondary metabolites. In orchids, bacterial endophytes play an essential role in the formation of mycorrhizae and the stability of relationships between plants and fungi. Endophytic bacteria can grow in orchids by producing phytohormones, doing photosynthesis, fixing nitrogen, promoting the mineral nutrition cycle, forming siderophores, and producing diverse beneficial metabolites to improve biomass production, stress tolerance, and biocontrol of potential phytopathogenic fungal species. This article examines how endophytic bacteria are associated with orchids and their potential growth-promoting abilities.

Macronutrients dynamics in copper-contaminated soils: Implications for hemp growth and its phytoremediation potential

Fibrous plants with higher biomass, particularly industrial hemp, have ability to withstand and accumulate significant quantities of heavy metals from contaminated environments. The present study aimed to evaluate the dynamics of different levels (ratios) of macronutrients nitrogen, phosphorus and potassium (NPK) viz., NPK1NPK (1:1:1); NPK2NPK (2:1:1); NPK3NPK (3:1:2); NPK4NPK (4:1:2) on hemp growth and Cu contents under various levels of Cu stress (100, 400 and 800 mg kg−1 on dry soil basis using CuSO4·5H2O). Results revealed that by increasing the Cu stress, growth and biomass decreased linearly and lipid per oxidation and enzymatic antioxidants increased. Balanced application of NPK improved the biomass and decreased the membrane damage by the modulation of malonaldehyde contents. Maximum concentration of Cu in roots (377.47 ± 4.90 mg kg−1), shoots (137.45 ± 5.60 mg kg−1) and (150.07 ± 3.57 mg kg−1) was recorded at Cu3NPK2 treatment as compared to control. Maximum translocation factor (TF) and bioaccumulation coefficients (BAC) in the shoots and leaves of hemp plant were noticed where Cu stress was applied at the rate of 100 mg kg−1. However, BAC and TF were below 1. The NPK2 treatment enhanced biomass and increase Cu content both in leaves and stems, rather than the roots. Our study suggests that balanced application of NPK is a practicable approach to alleviate Cu stress and improve biomass production of industrial hemp plant. These findings indicate that optimum nutrient supply, under Cu stress, can maximize the growth potential and overall health of industrial hemp, making it a viable option for phytoremediation and sustainable agriculture on contaminated soils.

Combined use of digestate and inorganic fertilizer alleviates the burden of class 1 integrons in perennial ryegrass rhizosphere without compromising aerial biomass production.

Antimicrobial resistance (AMR) is one of the main global health challenges. Anaerobic digestion (AD) can significantly reduce the burden of antibiotic resistance genes (ARGs) in animal manures. However, the reduction is often incomplete. The agronomic use of digestates requires assessments of their effects on soil ARGs. The objective of this study was to assess the effect of digestate on the abundance of ARGs and mobile genetic elements (MGEs) in the rhizosphere of ryegrass (Lolium perenne L.) and to determine whether half-dose replacement of digestate with urea (combined fertilizer) can be implemented as a safer approach while maintaining a similar biomass production. A greenhouse assay was conducted during 190days under a completely randomized design with two experimental factors: fertilizer type (unfertilized control and fertilized treatments with equal N dose: digestate, urea and combined fertilizer) and sampling date (16 and 148days after the last application). The results indicated that the digestate significantly increased the abundance of clinical class 1 integrons (intI1 gene) relative to the unfertilized control at both sampling dates (P < 0.05), while the combined fertilizer only increased them at the first sampling. Sixteen days after completing the fertilization scheme only the combined fertilizer and urea significantly increased the biomass production relative to the control (P < 0.05). Additionally, by the end of the assay, the combined fertilizer showed significantly lower levels of the macrolide-resistance gene ermB than digestate and a cumulative biomass similar to urea or digestate. Overall, the combined fertilizer can alleviate the burden of integrons and ermB while simultaneously improving biomass production.

Selection of microalgae in artificial digestate: Strategies towards an effective phycoremediation

Digestate is a complex by-product of anaerobic digestion and its composition depends on the digestor inputs. It can be exploited as a sustainable source of nutrients for microalgae cultivation but its unbalanced composition and toxic elements make the use challenging. Screening algae in a simplified synthetic digestate which mimics the main nutrient constraints of a real digestate is proposed as a reproducible and effective method to select suitable species for real digestate valorisation and remediation.Growth performance, nutrient removal and biomass composition of eight microalgae exposed to high amounts of NH4+, PO4− and organic-C were assessed. Using a score matrix, A. protothecoides, T. obliquus, C. reinhardtii, and E. gracilis were identified as the most promising species. Thus, three strategies were applied to improve outcomes: i) establishment of an algal consortium to improve biomass production, ii) K+ addition to the medium to promote K+ uptake over NH4+ and to reduce potential NH4+ toxicity, iii) P starvation as pretreatment for enhanced P removal by luxury uptake.The consortium was able to implement a short-term response displaying higher biomass production than single species (3.77 and 1.03–1.89 mg mL−1 respectively) in synthetic digestate while maintaining similar nutrient remediation, furthermore, its growth rate was 1.6 times higher than in the control condition. However, the strategies aiming to reduce NH4+ toxicity and higher P removal were not successful except for single cases. The proposed algal screening and the resulting designed consortium were respectively a reliable method and a powerful tool towards sustainable real digestate remediation.

Differential Mechanisms of Tolerance and Accumulation in Cajanus cajan (L.) Millsp. and Canavalia ensiformis (L.) DC in Response to Soil Manganese Concentration

ABSTRACT Cajanus cajan and Canavalia ensiformis are commonly used as cover crops due to their high biomass production, in addition they are also applied in recovery strategies for degraded areas. The objective of this study is to compare the tolerance, accumulation and translocation of Mn in the tissues of C. cajan and C. ensiformis, based on biomass production and the effects on the photosynthetic apparatus between species. The experiment was carried out in Red Latosol, contaminated with MnCl2 in the following concentrations: 0 (control), 80, 100, 120, 140 and 160 mg kg−1. Mn doses resulted in differentiated absorption, translocation and accumulation in plant organs, generating changes in the photosynthetic apparatus, reduction in dry mass and growth, and variations in tolerance and translocation levels between species. According to the results obtained, both species proved to be tolerant Mn and can be used in manganese management systems, they’re able to accumulate Mn in tissues, and not only maintain but also improve biomass production at intermediate doses, C. cajan indicates to be a better option for phytostabilization of Mn, on the other hand C. ensiformis, indicates to be a better option for phytoextraction of Mn in soils with contents up to 160 mg kg−1.

Determination of feed yield and quality parameters of whole crop durum wheat (Triticum durum Desf.) biomass under agrivoltaic system

Agrivoltaics represents a key technology for reaching sustainable development goals by reducing the competition between land used for food, for feed, and for electricity. It has been demonstrated that Agrivoltaics can increase land productivity and play a role in the expansion of renewable energy production. This work aimed to study the yield and nutritional characteristics, as well as feeding value for ruminants of Durum wheat biomass grown under agrivoltaic. Two years of controlled experiments revealed that the reduction in light moderately limited wheat yields in the phenological phase of soft dough in standard agrivoltaic trackers (i.e. with a Ground Coverage Ratio (GCR) = 13%), otherwise under extended trackers (i.e. GCR = 41%), the yields was reduced compared to control in whole light. The digestible neutral detergent fiber evaluated after 24 h of in situ rumen incubations increased with shading, resulting in different ratios of acid detergent lignin. More shaded theses also had superior crude and soluble proteins, acid detergent-insoluble protein, acid and neutral detergent fiber than the control. The biomass in the shaded treatments showed a better Ca: P ratio for ruminant nutrition. These characteristics are strategic in forage production, allowing a more flexible harvesting strategy. This additional contribution of the nutritional characteristics of Durum wheat produced on Agrivoltaic Systems could allow a better inclusion of the different types in diets and better management of silage or hay harvesting sites. These results might be helpful in improving biomass production and give valuable information on Durum Wheat under the Agrivoltaic System.

Detection of QTLs controlling flowering in a cross-pollinated F1 population of Miscanthus sinensis

Miscanthus is a perennial rhizomatous grass belonging to Andropogoneae, which is now used as lignocellulosic biomass crop. Miscanthus has a short history of domestication, so further breeding effort for improved biomass production is needed. Flowering plays a critical role in controlling vegetative growth and physiology of plant, so this study focused on finding quantitative trait locus controlling flowering of Miscanthus for use in marker assisted breeding. A cross-pollinated M. sinensis F1 population consisted of 278 progenies was produced, transplanted to the field and assessed in their flowering traits. Julian dates of flag leaf extension, first heading, half heading, first flowering, and half flowering were assessed in 2019, the third year after transplanting when Miscanthus was well established. The average Julian dates of the flowering traits were 198±9, 224±14, 233±14, 239±15 and 253±12, respectively, and showed a proximal normal distribution. Genotype by sequencing conducted by Illumina-hiseq using leaf DNA samples revealed the genetic map consisted of 1988 SNPs with average distance of 1.35 cM. Nine QTLs controlling flowering were detected exceeded 60% of LOD score threshold. These QTLs were neighboring 16 SNP markers, 5 of which were contained in known functional genes including RGL2 (gibberellin pathway regulation). Genetic map and marker information acquired through this study, including either annotated or not annotated markers, are expected to help understand and help breeding new Miscanthus in the future with desired flowering.

PagARGOS promotes low-lignin wood formation in poplar.

Wood formation, which occurs mainly through secondary xylem development, is important not only for supplying raw material for the 'ligno-chemical' industry but also for driving the storage of carbon. However, the complex mechanisms underlying the promotion of xylem formation remain to be elucidated. Here, we found that overexpression of Auxin-Regulated Gene involved in Organ Size (ARGOS) in hybrid poplar 84 K (Populus alba × Populus tremula var. glandulosa) enlarged organ size. In particular, PagARGOS promoted secondary growth of stems with increased xylem formation. To gain further insight into how PagARGOS regulates xylem development, we further carried out yeast two-hybrid screening and identified that the auxin transporter WALLS ARE THIN1 (WAT1) interacts with PagARGOS. Overexpression of PagARGOS up-regulated WAT1, activating a downstream auxin response promoting cambial cell division and xylem differentiation for wood formation. Moreover, overexpressing PagARGOS caused not only higher wood yield but also lower lignin content compared with wild-type controls. PagARGOS is therefore a potential candidate gene for engineering fast-growing and low-lignin trees with improved biomass production.

Potential of a chicken manure concentrate additive for Arthrospira maxima (Cyanophyceae): biochemical characterization and phycocyanin production

ABSTRACT Livestock manure is an eco-friendly and economical substrate for culturing microalgae. Chicken manure (CM) contains many organic nutrients, such as carbon, nitrogen and phosphorus, that are essential for microalgal growth. However, few studies have used CM to culture Arthrospira maxima, which has broad applications in the biofuel, pharmaceutical, food and feed industries, and is a candidate microalga for the treatment of animal waste. In this study, the use of CM concentrate (CMC) as an additive for A. maxima was evaluated. Zarrouk’s medium was combined with 0.5%, 1% and 1.5% (v/v) CMC. Fed-batch and batch culture methods were applied, and the biomass production and biochemical components of A. maxima were investigated. Fed-batch culture in a medium supplemented with 0.5% CMC resulted in the highest biomass production (1.86 ± 0.06 g l–1) and crude phycocyanin concentration (78.44 ± 0.20 mg g–1) on day 51 of culture, with significant differences compared to those in other groups (P < 0.05). However, significant differences among culture conditions were not observed in other biochemical components. This study demonstrates the newly established CMC-added cultivation method as a highly feasible strategy for industrial applications owing to its improved biomass production and nutritional advantages associated with increased phycocyanin concentration.