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Ammonia, a major stress-inducing factor in aquaculture, contributes a significant challenge in maintaining sustainable fish production. Addressing this issue requires environmentally and economically sustainable solutions. This study explores the use of readily available and environmentally friendly porous lignocellulosic luffa sponge as a biostimulator, with a combination of three medicinal and aromatic plants(MAPs) viz. Asparagus racemosses (satavari) roots, Cammiphora wightii (guggal) stems, and Vitex negundo (nirgundi) stem for alleviating ammoniacal stress by biotransforming ammonia in aquaponics water/ aquaculture. A 45-day experiment was conducted using Pangasianodon hypophthalmus in tanks containing aquaponics water. The study consists of a control (C) and four treatments: L(Luffa), LS(Luffa + shatavari roots), LG(Luffa + guggal stem) and LN(Luffa + nirgundi stem). Ammonia was spiked weekly at different concentrations(2, 2.5, 3, 5, and 10 mgL -1 ). The L group showed significantly( p  < 0.05) higher ammonia removal of 86.06% ± 9.62(spiked 3 mgL -1 ) in 24 hrs, and 73.98%±2.6 and 86.35%±4.47(spiked 5 mgL -1 ) in 24 and 48 hrs, respectively, which may be attributed to a higher surface area of the substrate for microbial attachment. The MAPs upregulated fish's hematological and serum biochemical parameters under elevated ammonia, indicating ammonical stress mitigation. Treatment groups showed significantly ( p  < 0.05) higher fish yield than the control (165.66 ± 0.50 g), with L, LS, LG, and LN giving a yield of 174.76 ± 2.07, 175.41 ± 0.59, 179.07 ± 4.29, and 181.57 ± 0.45 g respectively, with no significant difference detected among them. Promising outcomes in ammonia removal and stress mitigation were demonstrated by incorporating the lignocellulosic biomass and MAPs in this study, which is beneficial in commercial aquaculture with prospects in aquaponics systems.

This research appraised the simultaneous biofixation, that is not quite common in scientific literature, of carbon dioxide (CO2) and nitric oxides (NOx) by microalgae species Chlorella vulgaris, Haematococcus pluvialis, and Scenedesmus subspicatus. The experimental design was established by five treatments with gas concentrations between control—0.04% of CO2, 5 to 15% of CO2, and 30 to 100 ppm of NOx. Parameters such as pH, growth, productivity, lipids, protein, carbon/ nitrogen ratio, and astaxanthin were evaluated. For all species, the maximal growth and productivity were achieved with 5% of CO2 and 30 ppm of NOx. Regarding protein content, for all the three species, better results were obtained at higher concentrations of CO2 and NOx. These results prove the microalgae capacity for CO2 and NOx biofixation and reuse of biomass as a source of high value-added products, such as lipids, proteins, and astaxanthin. These findings support the indication of these species for flue gas treatment process and use in biorefineries systems. [ABSTRACT FROM AUTHOR]

Abstract Background Photosynthetic microalgae are emerging as potential biomass feedstock for sustainable production of biofuels and value-added bioproducts. CO2 biomitigation through these organisms is considered as an eco-friendly and promising alternative to the existing carbon sequestration methods. Nonetheless, the inherent relatively low photosynthetic capacity of microalgae has hampered the practical use of this strategy for CO2 biomitigation applications. Results Here, we demonstrate the feasibility of improving photosynthetic capacity by the genetic manipulation of the Calvin cycle in the typical green microalga Chlorella vulgaris. Firstly, we fused a plastid transit peptide to upstream of the enhanced green fluorescent protein (EGFP) and confirmed its expression in the chloroplast of C. vulgaris. Then we introduced the cyanobacterial fructose 1,6-bisphosphate aldolase, guided by the plastid transit peptide, into C. vulgaris chloroplast, leading to enhanced photosynthetic capacity (~ 1.2-fold) and cell growth. Molecular and physiochemical analyses suggested a possible role for aldolase overexpression in promoting the regeneration of ribulose 1,5-bisphosphate in the Calvin cycle and energy transfer in photosystems. Conclusions Our work represents a proof-of-concept effort to enhance photosynthetic capacity by the engineering of the Calvin cycle in green microalgae. Our work also provides insights into targeted genetic engineering toward algal trait improvement for CO2 biomitigation uses.

This work determined the nitrogen inputs, outputs and accumulation in compartments of stagnant earthen ponds for the monoculture and integrated multi‐trophic aquaculture (IMTA) of the Amazon river prawn (Macrobrachium amazonicum) and tambaqui (Colossoma macropomum), using recycled hypereutrophic water. A completely randomized experiment was designed with four treatments and three replications: PM–monoculture with 30 prawns/m2, FM ‐ monoculture with 3 fish/m2, IMTA ‐ polyculture with 30 prawns/m2 and 30 fish/m2 free, POLY‐CAGE ‐ polyculture with 30 prawns/m2 free and 40 fish/m3 in net‐cages. Animals, rain, water, feed, soil, gas, accumulated sludge, and suspended sediments were collected throughout the experiment to determine their nitrogen contents and to calculate the nitrogen budget. Results showed that much of the nitrogen available escapes to atmosphere as N2 (~40%–56%) after denitrification or accumulated within bottom sludge (~14%–42%). The remaining nitrogen was converted in animal biomass (~5%–21%) or was discharged to receiving waterbodies in the outlet water (~11%–13%). Feed management appeared to influence the major biological processes in the aquatic nitrogen cycle, such as photosynthesis and denitrification. The fish‐prawn IMTA systems converted approximately 53%–75% of feed nitrogen into harvestable products, which is more efficient than the 19%–46% of feed nitrogen converted in the monocultures. However, a large amount of nitrogen is accumulated in the pond bottom in all systems. An increased prawn density or the addition of a mud‐feeder species to the culture may enhance the incorporation of this material in harvested biomass, improving the efficiency of the systems. [ABSTRACT FROM AUTHOR]

Practices of aquaculture production may generate potential pollutants that cause environmental pressure. In this context, a recommendation to mitigate the environmental impacts caused by aquaculture waste would be using and recycling such nutrients, considered as "pollutants," in an eco-efficient way, with approaches such as the integrated multi-trophic aquaculture (IMTA). This system integrates the culturing of organisms with different and complementary ecosystem functions. This study aimed to investigate the ecosystem capacity of Ulva lactuca in wastewater bioremediation in an IMTA system with mussel and fish effluents. For such, three systems were set up: (1) algae cultivated with seawater, (2) algae with effluent from fish, and (3) algae with effluent from fish and mussels. Ulva lactuca proved to be a suitable species for the IMTA system with high growth and easy handling in cultivation. Algal growth rate, nutrient uptake (N and P) and O2 production increased significantly as the succession of trophic levels increased, demonstrating the high ecosystem capacity of U. lactuca for wastewater bioremediation as well as the use and recycling of eutrophication agents for biomass production. The highest absorption/removal of dissolved nitrogen occurred in the form of NH4+, a N form with the greatest metabolic advantage for photosynthetic assimilation, but toxic in high concentrations. The present IMTA system showed a balance between inputs and outputs, denoting sustainable and efficient characteristics of several ecosystem goods and services. [ABSTRACT FROM AUTHOR]

Background: Photosynthetic microalgae are emerging as potential biomass feedstock for sustainable production of biofuels and value-added bioproducts. CO2 biomitigation through these organisms is considered as an eco-friendly and promising alternative to the existing carbon sequestration methods. Nonetheless, the inherent relatively low photosynthetic capacity of microalgae has hampered the practical use of this strategy for CO2 biomitigation applications. Results: Here, we demonstrate the feasibility of improving photosynthetic capacity by the genetic manipulation of the Calvin cycle in the typical green microalga Chlorella vulgaris. Firstly, we fused a plastid transit peptide to upstream of the enhanced green fluorescent protein (EGFP) and confirmed its expression in the chloroplast of C. vulgaris. Then we introduced the cyanobacterial fructose 1,6-bisphosphate aldolase, guided by the plastid transit peptide, into C. vulgaris chloroplast, leading to enhanced photosynthetic capacity (~ 1.2-fold) and cell growth. Molecular and physiochemical analyses suggested a possible role for aldolase overexpression in promoting the regeneration of ribulose 1,5-bisphosphate in the Calvin cycle and energy transfer in photosystems. Conclusions: Our work represents a proof-of-concept effort to enhance photosynthetic capacity by the engineering of the Calvin cycle in green microalgae. Our work also provides insights into targeted genetic engineering toward algal trait improvement for CO2 biomitigation uses. [ABSTRACT FROM AUTHOR]

The aim of the present study is to investigate the potential of flue gases to be efficiently and economically applied in production of algal biomass in a photobioreactor (PBR). Various microalgae strains (Chlorella sorokiniana 211-234, Bracteacoccus minor 61.80, Radiosphaera negevensis 87.80, Chlorosarcinopsis negevensis 67.80 and Chlorococcum novae-angliae 5.85) had been tested for CO2 mitigation, growth and tolerance to high CO2 levels. The flue gas and CO2 bubbling induced a significant algal mass growth compared to control (ambient air). Removal of CO2 and NO by the studied microalgae strains was found to be 44% and 33% along daily intervals, respectively. A growth rate of ~0.4g L-1 d-1 was obtained for all algal species tested. Growth conditions for tested algae can be optimised through PBR technology in order to obtain highest biomass yield for production of valuable biochemicals (i.e., low-cost biofuel). [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A novel chlorophyte Desmodesmus sp. 3Dp86E-1 isolated from a White Sea hydroid Dynamena pumila was cultivated at CO levels from atmospheric (the 'low-CO' conditions) to pure carbon dioxide (the 5, 20, and 100 % CO conditions) under high (480 μE/(m s) PAR) light. After 7 days of cultivation, the '100 % CO' (but not 5 or 20 % CO) cells possessed ca. four times higher chlorophyll content per dry weight (DW) unit than the low-CO culture. The rate of CO fixation under 100 % CO comprised ca. 1.5 L/day per L culture volume. After a lag period which depended on the CO level, biomass accumulation and volumetric fatty acid (FA) content of the Desmodesmus sp. 3Dp86E-1 bubbled with CO-enriched gas mixtures increased and was comparable to that of the culture continuously bubbled with air. Under the low-to-moderate CO conditions, the FA percentage of the algal cells increased (to 40 % DW) whereas under high-CO conditions, FA percentage did not exceed 15 % DW. A strong increase in oleate (18:1) proportion of total FA at the expense of linolenate (18:3) was recorded in the '100 % CO' cells. Electron microscopy and pulse-amplitude-modulated chlorophyll fluorescence investigation revealed no damage to or significant downregulation of the photosynthetic apparatus in '100 % CO' cells grown at the high-PAR irradiance. Possible mechanisms of high-CO tolerance of Desmodesmus sp. 3Dp86E-1 are discussed in view of its symbiotic origin and possible application for CO biomitigation. [ABSTRACT FROM AUTHOR]

Recent developments in the field of microalgal biotechnology, including CO biomitigation and the discovery of new species of microalgae that are tolerant to extremely high CO levels (40-100 vol%), have renewed interest in the physiological effects and mechanisms of high-CO tolerance in photoautotrophs. Photosynthetic apparatus state transitions that increase ATP generation, upregulation of H-ATPases pumping protons out of the cell, rapid shutdown of CO-concentrating mechanisms, and adjustment of membranes' fatty acid composition are currently believed to be the key mechanisms governing cellular pH homeostasis and hence microalgae's tolerance to high CO levels, which is especially characteristic of extremophile and symbiotic species. The mechanisms governing acclimation to high CO comprise the subject of this review and are discussed in view of the use of CO enrichment to increase the productivity of microalgal cultures, as well as the practice of carbon capture from flue gases. [ABSTRACT FROM AUTHOR]

Integrated multi-trophic aquaculture (IMTA) seeks to biodiversify fed aquaculture (e.g. finfish or shrimps) with extractive aquaculture, recapturing the inorganic (e.g. seaweeds) and organic (e.g. suspension- and deposit-feeders) nutrients from fed aquaculture for their growth. The combination fed/extractive aquaculture aims to engineer food production systems providing both biomitigative services to the ecosystem and improved economic farm output through the co-cultivation of complementary species. Major rethinking is needed regarding the definition of an 'aquaculture farm' and how it works within an ecosystem. The economic values of the environmental/societal services of extractive species should be recognized and accounted for in the evaluation of the full value of these IMTA components. Seaweeds and invertebrates produced in IMTA systems should be considered as candidates for nutrient/carbon trading credits. While organic loading from aquaculture has been associated with localized benthic impacts, there have also been occurrences of increased biodiversity and abundance of wild species in response to moderate nutrient enrichment and the use of infrastructures as substrates. To develop efficient food production systems, it will be important to understand and use the duality of nutrients (essential when limiting/polluting when in excess) to engineer systems producing them in moderation so that they can be partially recaptured while maintaining their concentrations optimal for healthy and productive ecosystems. Measures of species diversity, colonization rates, abundance, growth and ecosystem functions with respect to nutrient partitioning and recycling, species interactions and control of diseases could represent valid indicators for the development of robust performance metrics. [ABSTRACT FROM AUTHOR]

Abstract: Integrated multitrophic aquaculture (IMTA) aims to be an ecologically balanced aquaculture practice that co-cultures species from multiple trophic levels to optimise the recycling of farm waste as a food resource. It provides an opportunity for product diversification and an increase in economic return if managed at the optimal stocking densities for each co-cultured species. A generic IMTA ecosystem model, incorporating dynamic energy budgets for a number of co-culture species from different trophic levels was developed to design IMTA farms for optimisation of multispecies productivity. It is based on the trophic similarity in the ecophysiological behaviour of cultured organisms to describe the uptake and use of energy. This approach can accommodate different species within a trophic group and is transferable to IMTA operations based on finfish–shellfish-detritivore-primary producer systems. Model simulations were firstly performed considering the monoculture of mussels and finfish, each “farm” interacting with the natural variability of the local environment. The next step was running the IMTA model with the co-culture groups added in: one run was with finfish as the key species in co-culture with seaweed and sea cucumbers and the other with mussels as the key culture species in association with seaweed and sea cucumbers. Scenario simulations show that conversion from monoculture to IMTA would considerably reduce waste products and increase farm productivity. Although the development of IMTA practices will depend on acceptable levels of waste products, feasibility and profitability of culture operations, the IMTA model provides a research tool for designing IMTA practices and to understand species interactions and predict productivity of IMTA farms. The refinement of the model and its power to predict multispecies productivity depends on emerging data from trial and commercial sea-based IMTA operations. [Copyright &y& Elsevier]

Background: Photosynthetic microalgae are emerging as potential biomass feedstock for sustainable production of biofuels and value-added bioproducts. CO 2 biomitigation through these organisms is considered as an eco-friendly and promising alternative to the existing carbon sequestration methods. Nonetheless, the inherent relatively low photosynthetic capacity of microalgae has hampered the practical use of this strategy for CO 2 biomitigation applications., Results: Here, we demonstrate the feasibility of improving photosynthetic capacity by the genetic manipulation of the Calvin cycle in the typical green microalga Chlorella vulgaris . Firstly, we fused a plastid transit peptide to upstream of the enhanced green fluorescent protein (EGFP) and confirmed its expression in the chloroplast of C. vulgaris . Then we introduced the cyanobacterial fructose 1,6-bisphosphate aldolase, guided by the plastid transit peptide, into C. vulgaris chloroplast, leading to enhanced photosynthetic capacity (~ 1.2-fold) and cell growth. Molecular and physiochemical analyses suggested a possible role for aldolase overexpression in promoting the regeneration of ribulose 1,5-bisphosphate in the Calvin cycle and energy transfer in photosystems., Conclusions: Our work represents a proof-of-concept effort to enhance photosynthetic capacity by the engineering of the Calvin cycle in green microalgae. Our work also provides insights into targeted genetic engineering toward algal trait improvement for CO 2 biomitigation uses.