Biostimulant Extracts from
Tetradesmus obliquus
Cultivated in Rice Parboiling Effluent Improve Rice Germination and Generate PUFA-rich Residues in a Circular Biorefinery Strategy
Aug 2026· Green Energy and Environmental Technology· 0 citations· 83 references
TL;DR
Findings demonstrate that T. obliquus cultivated in AIE preserves bioactive functionality and supports circular biorefinery strategies integrating wastewater remediation, agricultural biostimulant production, and lipid valorization for potential aquaculture applications.
Abstract
The valorization of agro-industrial effluents (AIEs) as cultivation media for microalgae represents a promising strategy for integrating wastewater remediation with bioproduct generation. The increasing demand for sustainable and climate-resilient agricultural systems, combined with the need to reduce microalgal production costs, has intensified interest in circular biorefinery approaches capable of converting industrial residues into bioactive compounds. In this context,
Tetradesmus obliquus
demonstrates strong potential for the production of agricultural biostimulants and nutritionally valuable metabolites. In this study,
T. obliquus
biomass cultivated in Bold’s basal medium (BBM) and rice parboiling AIE underwent biochemical characterization and aqueous extraction. Germination and seed vigor assays evaluated the biostimulant effects of the extracts on four rice cultivars (
Oryza sativa
L.) under standard and cold-stress conditions, while the residual biomass underwent lipid profiling by gas chromatography–mass spectrometry. AIE-derived biomass showed higher total carbohydrate content (197.12 mg g⁻
1
) than BBM biomass (121.33 mg g⁻
1
), whereas BBM biomass presented higher chlorophyll levels (5.37 mg g⁻
1
). Amino acid profiles also differed between cultivation systems; BBM extracts contained higher proportions of glutamic acid, valine, and glycine, whereas AIE extracts showed enrichment in alanine, proline, and histidine, indicating metabolic adaptation to effluent-based cultivation. Despite these compositional differences, both extracts promoted comparable biostimulant effects, particularly at treatments 3L·100 kg⁻
1
seed, achieving germination rates above 97% in IRGA 424 RI relative to the control. These findings demonstrate that
T. obliquus
cultivated in AIE preserves bioactive functionality and supports circular biorefinery strategies integrating wastewater remediation, agricultural biostimulant production, and lipid valorization for potential aquaculture applications.
Grape pomace is a promising agro-industrial residue with significant potential for sustainable biorefinery applications due to its high content of bioactive compounds and nutrients. This study evaluated its use as a substrate for Tetradesmus obliquus cultivation in photobioreactors and its effects on biomass growth and biochemical composition.
Three photobioreactors were operated using Bold’s Basal Medium (BBM): one supplemented with grape pomace extract obtained by acid hydrolysis (E1), another with grape pomace extract obtained by microwave-assisted ethanol extraction (E2), and a control containing only BBM. Microalgal cultivation was monitored for 30 days by measuring cell density, growth kinetics, and pH. After cultivation, lipid profile, protein content, mineral accumulation, antioxidant activity, and cellulose crystallinity were analyzed.
All treatments exhibited typical growth kinetics, with an exponential growth phase between days 5 and 10 and maximum cell density on day 26. E2 promoted the highest biomass growth, reaching 1.34 × 10
7
cells mL
−1
and a specific growth rate of 0.083 day
−1
. In contrast, E1 improved biomass quality by increasing protein content, antioxidant activity, and cellulose crystallinity, while reducing the proportion of saturated fatty acids.
Grape pomace extracts effectively modulated the growth and metabolism of Tetradesmus obliquus. While E2 favored biomass productivity, E1 enhanced the biochemical characteristics of the biomass, demonstrating the potential of grape pomace as a sustainable substrate for microalgal cultivation and supporting its application in integrated biorefinery processes.
Amanda Fonseca Leitzke, Diego Serrasol do Amaral, Raniel Campos Wrege et al.· Frontiers in Chemical Engine...· 0 citations
Wheatgrass (Triticum aestivum L.), the young shoot of common wheat, has attracted increased interest as a functional microgreen due to its rich phytochemical profile and reported nutritional and bio functional properties. This review summarises cultivation practices, biochemical composition and reported medicinal attributes of wheatgrass. Wheatgrass is a concentrated source of chlorophyll, phenolic compounds, flavonoids, essential amino acids, vitamins (A, C, E and B-complex) and enzymatic antioxidants such as catalase and superoxide dismutase. Among the many pharmacological effects these bioactive elements support is antioxidant, anti-inflammatory, anti-ulcer, anti-diabetic, antibacterial, detoxifying and may exhibit anticancer effects, as suggested by preliminary experimental studies actions. Cultivation approaches such as hydroponics and soil-based systems enable sustainable production of wheatgrass biomass including in urban and space-limited environments. Under optimised light and substrate conditions, elevated chlorophyll and phenolic levels enhance its potential nutritional and functional relevance. Findings from several in vitro and animal-based studies suggest potential applicability of wheatgrass in nutraceutical development. Its more general use depends on further standardising growth conditions, phytochemical extraction techniques and clinical confirmation. This review aims to highlight the botanical significance of wheatgrass as a sustainable microgreen and its potential role in nutrition-focused food system.
R. Manju, T. Jayanti, B. Shivangi et al.· Plant Science Today· 0 citations
Enhanced soil salinity is a major constraint to rice production in the coastal regions of Bangladesh. Salinity stress impairs nutrient uptake and induces ionic toxicity and osmotic stress, while excessive use of chemical fertilizers degrades soil health and causes environmental pollution. A novel salt-tolerant endophytic fungus, Aspergillus welwitschiae Ocstreb1, isolated from the halophytic wild rice Oryza coarctata, exhibited multiple plant growth–promoting traits under both non-saline and 900 mM salt-stress conditions in vitro. These findings suggest that Ocstreb1-based biofertilizer could serve as an eco-friendly and cost-effective alternative to enhance rice productivity under saline conditions. In this experiment, the biofertilizer was prepared using fungal spores produced on wheat bran and subsequently mixed with talcum powder as a carrier. Field trials were conducted following a randomized complete block design (RCBD), incorporating different levels of chemical fertilizer application (0%, 80%, and 100% of the BRRI-recommended NPKSZn rates) in both biofertilizer-treated and untreated plants. Compared with the 100% chemical fertilizer treatment, the combined application of biofertilizer and 80% chemical fertilizer resulted in a comparable yield in Barguna and increased yield of 196.6 kg ha⁻¹ in Satkhira. Profitability analysis showed that this treatment provided an additional economic benefit of USD 48–68 ha⁻¹ over the 100% chemical fertilizer treatment. Moreover, fumonisin B1 levels in grains from biofertilizer-treated plants were negligible. In conclusion, commercial production of this biofertilizer will pave the way for enhancing rice yield with less use of chemical fertilizer while promoting sustainable agricultural practice particularly in areas affected by salinity stress.
Amit Chowdhury, J. Bhattacharya, Md. Iyasir Arafat et al.· Discover Agriculture· 0 citations
Global agricultural productivity is increasingly threatened by climate change, soil salinization, and freshwater scarcity. In response, edible halophytes such as Crambe maritima L. (sea kale) are emerging as resilient, promising alternative crops for biosaline agriculture. This review comprehensively evaluates the agronomic, phytochemical, and commercial potential of C. maritima and related Crambe species. We examine current propagation protocols and highlight the application of controlled-environment agriculture (CEA) to leverage “saline eustress,” strategically enhancing secondary metabolite biosynthesis without penalizing harvestable biomass. Nutritionally, Crambe species exhibit a highly favorable profile, selectively accumulating essential macro- and micro-minerals alongside potent bioactive compounds, particularly characteristic glucosinolates, including sinigrin, together with diverse phenolic acids. These specific secondary metabolites confer antioxidant defense system and antimicrobial properties, positioning the genus as an unexploited resource for functional foods, nutraceuticals, and cosmeceuticals. However, successfully transitioning C. maritima from a wild coastal halophyte into a reliable horticultural crop necessitates overcoming critical domestication bottlenecks, including mechanical seed dormancy, polygenic salinity tolerance, and a scarcity of long-term field data. By addressing these multidisciplinary challenges through targeted breeding and advanced agronomy, C. maritima represents a highly promising candidate for dietary diversification and the advancement of climate-resilient agricultural systems.
Tatiana Pagan Loeiro Cunha-Chiamolera, Ignacio Rodríguez-García, M. Urrestarazu et al.· Horticulturae· 0 citations
The increasing need for sustainable agricultural practices has intensified interest in seaweed-based biostimulants and plant growth-promoting rhizobacteria (PGPR) as eco-friendly alternatives to chemical fertilisers. This study examined the individual and combined effects of Sargassum wightii extract and PGPR strains (Azospirillum lipoferum TSA-6 and Bacillus megaterium TSB-3) on the growth and yield of tomato (PKM-1) under pot culture conditions. Seaweed extracts obtained through hot-water and solvent extraction were screened for phytochemicals and endogenous growth hormones (IAA, GA₃ and cytokinin). Among the six species analysed, S. wightii exhibited the highest levels of auxin (3.7 mg L-1) and cytokinin (4.9 mg L-1). Preliminary screening using crude extract showed that a 2.5 % concentration significantly enhanced germination, seedling vigour, root and shoot length and leaf area index. In the pot experiment, the integrated treatment comprising 75 % recommended dose of fertilisers (RDF) + 2.5 % S. wightii extract + A. lipoferum + B. megaterium (T8) recorded superior growth and yield attributes, including increased dry matter production, fruit number, fruit weight and total fruit yield, comparable to 100 % RDF. The results demonstrate that the combined application of S. wightii extract and PGPR can effectively enhance tomato productivity while reducing fertiliser usage by 25 %. This integrated biostimulant strategy offers a sustainable approach to improving crop performance and reducing chemical fertiliser dependence.
K. Oviya, J. Jaipriyanka, S. Mahalakshmi et al.· Plant Science Today· 0 citations
Seaweed-derived biostimulants may complement conventional nutrient management in rice, but their performance requires evaluation under specific soil and agroclimatic conditions. A field experiment was conducted during the kharif season of 2022–2023 at the Agricultural Research Farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, to assess Sagarika seaweed extract in an Inceptisol. The experiment followed a randomised block design with 11 treatments and three replications. Treatments included an absolute control, the recommended dose of fertilisers (RDF), reduced soil-applied urea, an NPK biofertiliser consortium, Sagarika granules, Sagarika liquid sprays, nano urea, and selected combinations of these inputs. Plant growth was recorded at 30, 60, and 90 days after transplanting, and yield attributes, grain yield, straw yield, biological yield, and harvest index were measured. Treatment T7, comprising 100% RDF, Sagarika granules at 10 kg acre⁻¹, and two Sagarika liquid sprays at 5 mL L⁻¹, recorded the highest numerical grain yield (61.63 q ha⁻¹), straw yield (77.02 q ha⁻¹), and biological yield (138.66 q ha⁻¹). Several fertilised treatments were statistically comparable with T7 based on the reported critical difference. The highest harvest index was recorded under T10 (44.95%). The findings indicate that integrated Sagarika treatments were associated with favourable rice growth and yield under the conditions evaluated. Multi-season and multi-location studies incorporating economic, soil-health, nutrient-use-efficiency, and environmental measurements are required before wider recommendations are made.
R. Meena, R. Meena, A. Meena et al.· Archives of Current Research...· 0 citations
