Search Results (69)

Aeroponics efficiently conserves water and fertilizer but faces energy sustainability challenges in maintaining high productivity and quality. This study aimed to identify critical growth phases of lettuce affected by management modes and assess resource/energy efficiency (cost per unit yield) to inform the development of sustainability strategies for lettuce production in a lettuce-dominant aeroponics system integrated with radish. Three management modes were tested: M1 (constant nutrient solution concentrations), M2 (variable nutrient solution concentrations), and M3 (combined variable nutrient solution concentrations and preharvest short-duration continuous light for 48 h). Plant parameters were dynamically measured in a 30-day cultivation cycle. The results showed that the intercropped lettuce exhibited peak growth at 15–25 days after transplanting, and nutrient solution adjustment enhanced the shoot weight and quality, with synergistic quality improvements under M3. However, preharvest lighting reduced the net photosynthetic rate via stomatal closure and lowered the effective quantum yield of photosystem II, preventing biomass increase. The preharvest short-duration continuous light elevated the soluble protein, ascorbic acid, and soluble sugar contents. For yield-focused systems, M2 alone achieved comparable shoot weight to M3 with higher energy efficiency. However, when simultaneously considering lettuce quality enhancement and the yield boost of radish in the intercropping system, M3 demonstrated potential for greater marginal benefits. Full article

Coke production generates up to 400 m³/min of flue gases containing 4% CO₂. This study evaluated the capacity of the microalga Halochlorella rubescens_UFPS013 to capture CO₂ from emissions generated by Excomin SAS (Colombia). A Central Composite Design and response surface methodology were employed to analyze the effects of CO₂ concentration and light–dark cycles on biomass production. The statistical model explained 99% of the observed variability, suggesting a robust foundation with room for further improvement. In situ test showed that H. rubescens_UFPS013 tolerated a flue gas flow rate of up to 0.587 L/min, achieving an optimal predicted biomass yield of 2 g/L under a 12.6 h photoperiod on day 20. The generated biomass exhibited significant protein (48.5%) and lipid (9.6%) content, highlighting its potential for industrial applications in the food and energy sectors. These findings underscore the role of H. rubescens_UFPS013 as a viable biotechnological tool for CO₂ capture in industrial processes, with prospects for scale-up and continuous optimization, contributing to sustainable solutions in emission reduction and the production of high-value bioproducts. Full article

The sustainable and economically viable production of microalgae biomass for biofuels and high-value bioproducts is highly dependent on precise, multi-parametric monitoring of cultivation systems. This review provides a comprehensive overview of current approaches and technological advances in multi-sensor systems applied to photobioreactors, including flow cytometry, IR spectroscopy, RGB sensors, in situ microscopy, and software-based sensors. The integration of artificial intelligence (AI), the Internet of Things (IoT) and metaheuristic algorithms into monitoring systems is also discussed as a promising way to optimise key ecological, physicochemical, and biological parameters in real time. The report highlights critical factors that influence biomass growth and product yield, such as nutrient concentrations, light intensity, CO₂ levels, pH and temperature. In addition, current technological limitations are highlighted, and future strategies for improving monitoring accuracy, automating cultivation, and improving the biosynthesis of metabolites are outlined. Through a synthesis of the literature and technological trends, this work contributes to the development of smart photobioreactor systems and provides actionable insights to improve large-scale, highly efficient microalgae cultivation in energy and environmental biotechnology. Full article

This study systematically investigated two ecotypes of Ulva prolifera, the dominant species responsible for green tides in the Yellow Sea, classified as Subtype I (strain I08-1) and Subtype II (strain QD-7). Both subtypes produce positively phototactic biflagellate gametes with oval/pear-shaped morphology but exhibit distinct cellular dimensions. Subtype I gametes demonstrated significantly larger cell sizes, with long and short axes measuring 6.55 μm and 4.62 μm, respectively, compared to Subtype II’s dimensions of 6.46 μm (long axis) and 3.03 μm (short axis). Developmental analysis revealed striking morphological divergence at the 6-day germling stage: Subtype I attained an average length of 1301.14 μm, more than doubling Subtype II’s 562.25 μm. Superior growth kinetics were observed in Subtype I, exhibiting enhanced specific growth rates (SGRs) across multiple parameters—main stem length (8.58% vs. 3.55%), primary branch elongation (19.17% vs. 12.59%), main stem width expansion (17.29% vs. 5.00%), and biomass accumulation (41.90% vs. 40.96% fresh weight). Chlorophyll quantification confirmed significantly higher pigment content in Subtype I. Pre-co-culture photosynthetic profiling demonstrated Subtype I’s superior quantum efficiency (α = 0.077 vs. 0.045) with marked differences in regulated energy dissipation (YNPQ) and non-photochemical quenching (NPQ). Post-co-culture physiological adaptation was evident in Subtype II, showing significant elevation of non-regulated energy dissipation quantum yield (YNO) and eventual surpassing of maximum electron transport rate (ETRmax) compared to Subtype I. These findings establish that U. prolifera employs robust photoprotective and thermal adaptation strategies under natural photothermal conditions. Crucially, YNO-based analysis revealed Subtype II’s enhanced high-light protection mechanisms and superior adaptability to intense irradiance environments. This research elucidates ecotype-specific environmental adaptation mechanisms in U. prolifera, providing critical insights for optimizing green tide mitigation strategies and advancing ecological understanding of algal bloom dynamics. Full article

Plant factories offer a promising opportunity for fresh food production due to their minimal land requirements. Among the adjustable factors in the production system of plant factories, light serves as a critical element, significantly influencing both crop yield and quality. Cilantro, a prevalent culinary herb and a traditional flavoring agent, plays a crucial role in Taiwanese gastronomy. This research investigated cilantro plants grown under nine different light treatments with varying red to far-red ratios and green light percentages over a 49-day period. Results demonstrate that maximum fresh and dry biomass accumulation in both shoot and root tissues occurred under treatments with red to far-red ratios of approximately of 1.8 combined with medium green light intensity. Conversely, medium far-red ratios negatively affected lutein and carotenoid concentrations in foliar tissues. Carotenoid biosynthesis exhibited an inverse relationship with green light intensity, with lower green light percentages corresponding to significantly higher carotenoid concentrations. In terms of energy efficiency, a red to far-red ratio of approximately 1.8 yielded the highest energy yield (g kWh⁻¹) and photon yield (g mol⁻¹), indicating optimal energy conversion efficiency under this spectral composition. In conclusion, this study demonstrates that cilantro cultivation under R53G05B13FR29 spectral composition (53% red, 5% green, 13% blue, 29% far-red) with a 49-day production cycle maximizes biomass while optimizing energy utilization efficiency. Full article

The alterable light/dark cycle in a plant factory with artificial lighting eliminates the traditional concept of day and night in nature. Adjusting the light/dark cycle to closely align with the inherent circadian rhythm of plants can enhance biomass accumulation. In this study, we examined the effects of different light/dark cycles on the photosynthetic performance, growth, and energy use efficiency of two hydroponic lettuce cultivars (Lactuca sativa L. cv. ‘Frillice’ and ‘Crunchy’). The lettuces were subjected to four light/dark cycle treatments—16 h light/8 h dark (L₁₆D₈, as control), 12 h light/6 h dark (L₁₂D₆), 8 h light/4 h dark (L₈D₄), and 4 h light/2 h dark (L₄D₂), all under LED lamps with white combined red chips at the same light intensity of 250 μmol m⁻² s⁻¹. Photosynthetic performance and growth index were measured during the slow and rapid growth stages, corresponding to days 9 and 21 after transplanting, respectively. For Frillice, L₁₂D₆ achieved the highest shoot dry weight and light and electricity energy use efficiencies on days 9 and 21 after transplanting, primarily due to the largest leaf area, leaf number, and net photosynthetic rate. For Crunchy, L₁₂D₆ and L₈D₄ increased shoot fresh and dry weights due to larger leaf area and leaf number on day 9 after transplanting compared with L₁₆D₈. Subsequently, the lettuces in L₁₆D₈ exhibited a rapid increase in leaf area and leaf number, along with a high net photosynthetic rate during the rapid growth stage, resulting in fast shoot biomass accumulation. There were no significant differences in the shoot dry weight and energy use efficiency between L₁₆D₈ and L₁₂D₆ on day 21 after transplanting. Two lettuce cultivars in L₁₆D₈ both exhibited the highest water use efficiency on day 21 after transplanting. In conclusion, the light/dark cycle lighting can alter lettuce biomass accumulation by modifying plant morphology and leaf net photosynthetic rate. Additionally, the physiological response to the light/dark cycle was cultivar-dependent. Our findings provide valuable insights for optimizing hydroponic lettuce production to achieve high yield in LED plant factories. Full article

Marine environments provide a unique opportunity to blend offshore wind energy production and marine fishery activities as complementary technologies. This study investigated the morphological characteristics (length and weight) and biomass yield of seaweed (Undaria pinnatifida) in a model marine environment with mariculture within an offshore wind farm in southwestern Korea. The mean lengths in the first cultivation trials of U. pinnatifida sporophytes increased from 1.8 ± 0.1 cm in November 2021 to 120–170 cm in March 2022 (density, 39.8 plants m⁻¹; final wet weight, 98.6–249.1 g (mean 146.8 ± 20.4 g, n = 20 ind.); yield 5842 g m⁻¹). Further, for the second cultivation trial, the length of the sporophytes increased from 1.5 ± 0.1 cm in November 2021 to 120–150 cm in April 2022 (density, 49.3 plants m⁻¹; final wet weight, 83.0–251.6 g (mean 155.7 ± 19.0 g; n = 20 ind.); yield, 7676 g m⁻¹), and, owing to the increase in water temperature and light intensity due to seasonal changes around the offshore wind power farm, the second cultivation trials showed signs of chlorosis. Considering the environment, we judged seaweed growth to be normal. Therefore, when applying this model to grow U. pinnatifida, seasonal temperature changes, the purpose of the product, and the nutritional status of the open-sea area should be considered. These results may improve seaweed farming in offshore wind farms in the future. Full article

Microalgae offer significant potential in diverse fields, including biofuels, carbon capture, and high-value bioproducts. However, optimizing and scaling microalgae cultivation systems present several challenges due to the dynamic interactions among environmental factors such as light intensity, temperature, pH, nutrient concentration, and CO₂ levels, as well as species-specific biological variability. Recent advancements in artificial intelligence (AI), particularly machine learning (ML) and automation, have provided innovative solutions to these challenges. This review explored the role of AI in enhancing microalgae technology, focusing on optimizing cultivation conditions, improving CO₂ capture, maximizing biomass production, and automating system processes. Key case studies highlight successful applications of AI in biofuel production, carbon capture projects, and high-value compound manufacturing. Key case studies demonstrate that AI-driven models can increase biomass productivity by up to 15–57%, improve CO₂ biofixation efficiency, and enhance lipid and high-value compound yields by more than 20–43% compared to traditional methods. Additionally, we discussed the limitations of current AI models, particularly in data availability and species-specific variability, and suggested future research directions to enhance the integration of AI and microalgae systems. By leveraging AI’s potential, microalgae technologies can become more efficient, scalable, and economically viable, addressing global sustainability challenges such as energy production and climate change mitigation. Full article

The increasing soil pollution has accelerated the implementation of new agricultural regulations that significantly limit the use of synthetic nitrogen (N) fertilizers. Consequently, plants are likely to experience nutrient stress, leading to decreased productivity and potential threats to food security. To address these critical challenges, microbial-based biostimulant (BS) products, which utilize metabolites from microorganisms, offer a sustainable and eco-friendly solution to mitigate plant nutrient stress. This study evaluated the effects of the radicular application of a microbial-based BS containing L-α-amino acids on lettuce and pepper crops under two nitrogen regimes: optimal N availability and N stress (NS). Various parameters, including growth, production, soluble proteins, photosynthetic pigment content, and oxidative stress markers, were assessed. Under optimal N conditions, BS application enhanced commercial biomass in lettuce and vegetative biomass in pepper, indicating that BSs can reduce the need for nitrate uptake and endogenous amino acid synthesis, thereby conserving energy for other physiological processes. Despite BS application, NS conditions significantly reduced vegetative and reproductive growth in both species. However, BS treatment in pepper plants increased chloroplast pigments, improving light absorption and photosynthetic efficiency. The reduction in the carotenoid/chlorophyll ratio suggests efficient N allocation to growth and production. Thus, BS application proved effective in mitigating NS in pepper plants, enhancing pepper production, while under optimal conditions, it improved lettuce yield, particularly commercial biomass. These findings underscore the potential of symbiotic microbial-based BSs as a promising tool for sustainable agriculture under reduced N availability. Full article

Fodder soybean (Glycine max L.) with high protein and yield is a popular forage grass in northeast China. Seasonal drought inhibits its growth and development during seedling stage. The objective of this study was to observe morpho-physiological changes in fodder soybean seedlings under melatonin (MT) treatments and identify appropriate concentration to alleviate the drought damage. Two varieties commonly used in northeast China were treated with 0, 50, 100, and 150 μM melatonin at soil water content of 30%. The results indicated that applying melatonin enhanced height, biomass and altered root morphology of fodder soybean seedlings under water-deficient conditions. The treatments with melatonin at different concentrations significantly reduced the contents of H₂O₂, O₂⁻ and MDA, while boosting the capacity of the antioxidant defense system and the content of osmotic adjustment substances. Meanwhile, increases in light energy capture and transmission efficiency were observed. Furthermore, treatment with melatonin regulated the expression levels of genes associated with photosynthesis and the antioxidant defense system. Notably, 100 μM melatonin treatment produced the most favorable effect in all treatments under drought conditions. These research results provide new information for enhancing the drought tolerance of fodder soybean using chemical measures. Full article

Light is a vital regulator of photosynthesis, energy production, plant growth, and morphogenesis. Although these key physiological processes are well understood, the effects of light quality on the pigment content, oxidative stress, reactive oxygen species (ROS) production, antioxidant defense systems, and biomass yield of plants remain largely unexplored. In this study, we applied different light-emitting diode (LED) treatments, including white light, red light, blue light, and a red+blue (1:1) light combination, to evaluate the traits mentioned above in alfalfa (Medicago sativa L.). Fluorescence staining showed that red light significantly triggered the oxidative stress indicators compared to blue and white light, while the combined red and blue light treatment significantly reduced the ROS (O₂^•−, H₂O₂) intensity in alfalfa seedlings. Interestingly, the combined light treatment significantly boosted the seed germination rate (%), maximum photochemical quantum yield of PSII (Fv/Fm), leaf greenness (SPAD score), photosynthetic pigment levels (chlorophyll a, chlorophyll b, and carotenoids), and plant biomass yield in alfalfa seedlings. The red and/or combined (red+blue) light treatments significantly regulated antioxidant enzymes (SOD, CAT, APX, and GR) and the expression of genes related to the ascorbate–glutathione (AsA-GSH) pathway, including monodehydroascorbate reductase (MsMDHAR), dehydroascorbate reductase (MsDHAR), ascorbate peroxidase (MsAPX), and glutathione reductase (MsGR). These results indicate that light quality is crucial for regulating the morphological, physiological, and molecular traits linked to alfalfa improvement. These findings suggest a new approach to enhancing the adaptation, as well as the morphological and agronomic yield, of alfalfa and forage legumes through light-quality-mediated improvement. Full article

The growing population and economic expansion have led to increased energy demand while presenting complex waste generation and management challenges, particularly in light of climate change. Green hydrogen, which is considered a major clean energy carrier, can also be generated from food waste through a process known as dark fermentation. The production of dark fermentative hydrogen from food waste and biomass residues, in general, is influenced by the type of feedstock, source of inoculum, and their pretreatment and handling strategies. Food waste is a suitable substrate for dark fermentation and has a variable and complex composition, which is a major factor limiting the hydrogen yield. This review critically assesses food waste sources, focusing on their physical and chemical composition, pretreatment methods, and strategies for optimizing dark fermentative hydrogen production. This paper also highlights and critically discusses various inoculum sources and innovations regarding the pretreatment and enrichment applications of inocula for dark fermentative hydrogen production. Based on the literature analysis, advanced research is required to develop more sustainable and specific pretreatment strategies that consider the properties of food waste and the source of the inoculum. This approach will aid in preventing inhibition and inefficiency during the dark fermentation process. Full article

Salt stress could be a significant factor limiting the growth and development of vegetables. In this study, Fulvic Acid (FA) (0.05%, 0.1%, 0.15%, 0.2%, and 0.25%) was applied under nitrate stress (150 mM), with normal Hoagland nutrient solution as a control to investigate the influence of foliar spray FA on spinach growth, photosynthesis, and oxidative stress under nitrate stress. The results showed that nitrate stress significantly inhibited spinach growth, while ROS (reactive oxygen species) accumulation caused photosystem damage, which reduced photosynthetic capacity. Different concentrations of FA alleviated the damage caused by nitrate stress in spinach to varying degrees in a concentration-dependent manner. The F3 treatment (0.15% FA + 150 mM NO₃⁻) exhibited the most significant mitigating effect. FA application promoted the accumulation of biomass in spinach under nitrate stress and increased chlorophyll content, the net photosynthetic rate, the maximum photochemical quantum yield of PSII (Photosystem II) (Fv/Fm), the quantum efficiency of PSII photochemistry [Y(II)], the electron transport rate, and the overall functional activity index of the electron transport chain between the PSII and PSI systems (PItotal); moreover, FA decreased PSII excitation pressure (1 − qP), quantum yields of regulated energy dissipation of PSII [Y(NPQ)], and the relative variable initial slope of fluorescence. FA application increased superoxide dismutase, peroxidase, and catalase activities and decreased malondialdehyde, H₂O₂, and O₂⁻ levels in spinach under nitrate stress. FA can enhance plant resistance to nitrate by accelerating the utilization of light energy in spinach to mitigate excess light energy and ROS-induced photosystem damage and increase photosynthetic efficiency. Full article

The increasing global population has raised concerns about meeting growing food demand. Consequently, the agricultural sector relies heavily on chemical fertilizers to enhance crop production. However, the extensive use of chemical fertilizers can disrupt the natural balance of the soil, causing structural damage and changes in the soil microbiota, as well as affecting crop yield and quality. Biofertilizers and biostimulants derived from microalgae and cyanobacteria are promising sustainable alternatives that significantly influence plant growth and soil health owing to the production of diverse biomolecules, such as N-fixing enzymes, phytohormones, polysaccharides, and soluble amino acids. Despite these benefits, naturally producing high-quality microalgal biomass is challenging owing to various environmental factors. Controlled settings, such as artificial lighting and photobioreactors, allow continuous biomass production, but high capital and energy costs impede large-scale production of microalgal biomass. Sustainable methods, such as wastewater bioremediation and biorefinery strategies, are potential opportunities to overcome these challenges. This review comprehensively summarizes the plant growth-promoting activities of microalgae and elucidates the mechanisms by which various microalgal metabolites serve as biostimulants and their effects on plants, using distinct application methods. Furthermore, it addresses the challenges of biomass production in wastewater and explores biorefinery strategies for enhancing the sustainability of biofertilizers. Full article

With a predominantly humid tropical climate and a large area for expanding agricultural activities, Angola has in principle favorable conditions for bioenergy production. The focus of this study was to evaluate the availability of suitable land for producing sugarcane. This crop is highly efficient in converting solar energy into biomass for energy purposes in Angola. To this end, this paper outlines a method for data collection, processing, and analysis divided into three sections. The first section uses the GAEZ (Global Agroecological Zones) database and QGIS (Quantum GIS) software (version 3.22.5) to assess land availability for sugarcane cultivation in Angola, classifying the regions’ suitability into four levels. The second section supplements this with data from the FAOSTAT database, systematically excluding areas with restrictions, such as protected zones, land already used for other crops, and regions unsuitable for sugarcane. Finally, the third section employs an agricultural yield model to estimate the potential yield of sugarcane based on climatic parameters and the amount of bioenergy (ethanol and bioelectricity) able to be produced in the available land. Under these criteria, this study identified the existence of 6.3 Mha in lands of good agricultural suitability, with water resources, corresponding to 5% of the Angolan territory, distributed in seven provinces of the country, especially in the provinces of Cuando Cubango and Cunene, where 85% of the very suitable land under irrigation is located. Adopting a model of agricultural productivity, assuming irrigation and adequate agricultural practices, such area could produce approximately 956 million tons of sugarcane annually, which is significantly higher than the current production in this country. This amount of feedstock processed using current technology could potentially produce 81.3 GL of ethanol and 176.9 TWh of electricity with low GHG emissions per year, which is able to mitigate, as a whole, circa 60.3 MtCO₂-eq/year by displacing gasoline in light vehicles and diesel and natural gas consumed in power generation. Full article