Algal Systems Research Articles

Advanced oxidation as tertiary treatment for recovery of effluent from an integrated algal pond system

AbstractIn contemporary water‐scarce regions and with increasing pressure on the built environment, access to quality water within the peri‐urban space is of concern. It has been argued that integrated algal pond systems (IAPS) are ideally suited as these systems offer value recovery and water for irrigation. Advanced oxidation (AO) was evaluated as tertiary treatment for inclusion into the IAPS process. Chemical oxygen demand (COD), total suspended solids (TSS) and ammonium‐N in effluent from an IAPS treating municipal sewage were monitored after exposure to AO. All measured parameters were reduced but reduction in COD occurred only after long‐term exposure or high dosage. COD, TSS and ammonium‐N concentrations were reduced by 2%, 30% and 28%, respectively, within 24 h. Addition of an AO unit to the IAPS process can upgrade water quality to a level satisfactory for recovery to irrigation or for discharge without any substantial increase in process footprint.

Evaluating wastewater treatment infrastructure systems based on UN Sustainable Development Goals and targets

A multi-criteria comparison of algal-based and activated sludge-based wastewater infrastructure systems based on 30 process parameters derived from the UN Sustainable Development Goals (SDGs) is presented to assess their environmental, economic, social, and overall sustainability. The classical high-rate algal ponds (HRAP) and an emerging mixotrophic algal system (A-WWT) were selected as algal-based systems; and the conventional activated sludge (CAS) system and the membrane bioreactor (MBR) system, as activated sludge-based systems. Visual PROMETHEE outranking software was adopted to determine the preference scores and ranking of the four systems under twelve distinct scenarios/priorities. The mixotrophic A-WWT emerged as the preferred technology in environmental, economic, and overall sustainability aspects resulting in net positive preference scores (0.40, 0.53, and 0.36, respectively). The MBR system outperformed all the other technologies from the social sustainability perspective due to its lower footprint and better-quality effluent including significant pathogen removal. Even though HRAP was preferred over the CAS system in the context of environmental sustainability (preference scores of −0.22 in HRAP vs −0.27 in CAS), preference scores for them were similar in the context of economic sustainability (−0.33 for HRAP and CAS), and lower from social (−0.14 in CAS vs −0.67 in HRAP) and overall sustainability (−0.22 in CAS vs −0.34 in HRAP) perspectives. Scenario-based assessments indicated that preference ranking is strongly dependent on the decision maker’s priorities. Good agreement between the findings from this study with literature reports adds credence to the validity of the proposed process parameters. Parameters and the method proposed herein could be useful in evaluating wastewater treatment technologies from a sustainability perspective.

Maximizing phosphorus recovery as biofertilizer in an algal wastewater treatment system

Our previous reports have demonstrated an algal pathway for treating settled sewage and recovering its energy-, nitrogen-, and phosphorous-contents via hydrothermal liquefaction (HTL) of the resulting algal biomass. The first part of the current study was to intensify a critical step in the phosphorous (P) recovery process which entails alkaline leaching of the P-rich byproduct of HTL– biochar, to yield a P-rich eluate. The following parameters driving the efficiency and cost of leaching P from biochar were systematically evaluated: leaching time, concentration of base eluent, mixing during leaching, liquid:solid (L:S) ratio in leaching, and temperature. Optimum leaching time, base concentration, L:S ratio, and temperature were found to be 72 h, 0.5 M, 20:1, and 60 °C, respectively. Under these optimal conditions, >86% of P in the biochar could be extracted at an estimated cost of $4.54/kg P. In the second part of this study, a three-step procedure was developed to recover high-purity biofertilizers from the P-rich eluate of biochar. In the first step, impurities along with 24.6% of P in the eluate were precipitated. In the second step, high-quality struvite (comprising 72.7% of P in the eluate) was precipitated from the supernatant of the first step. In the third step, the precipitate from the first step was dissolved and its P-content was re-precipitated as high-quality calcium phosphate. This three-step procedure resulted in 95.4% P-recovery from biochar eluate at $5.29/kg P. Reclaimed struvite and calcium phosphate were shown to be of high chemical purity, complying with US EPA guidelines for metals.

Different co-occurring bacteria enhance or decrease the growth of the microalga Nannochloropsis sp. CCAP211/78.

SummaryMarine photosynthetic microalgae are ubiquitously associated with bacteria in nature. However, the influence of these bacteria on algal cultures in bioreactors is still largely unknown. In this study, eighteen different bacterial strains were isolated from cultures of Nannochloropsis sp. CCAP211/78 in two outdoor pilot‐scale tubular photobioreactors. The majority of isolates was affiliated with the classes Alphaproteobacteria and Flavobacteriia. To assess the impact of the eighteen strains on the growth of Nannochloropsis sp. CCAP211/78, 24‐well plates coupled with custom‐made LED boxes were used to simultaneously compare replicate axenic microalgal cultures with addition of individual bacterial isolates. Co‐culturing of Nannochloropsis sp. CCAP211/78 with these strains demonstrated distinct responses, which shows that the technique we developed is an efficient method for screening the influence of harmful/beneficial bacteria. Two of the tested strains, namely a strain of Maritalea porphyrae (DMSP31) and a Labrenzia aggregata strain (YP26), significantly enhanced microalgal growth with a 14% and 12% increase of the chlorophyll concentration, respectively, whereas flavobacterial strain YP206 greatly inhibited the growth of the microalga with 28% reduction of the chlorophyll concentration. Our study suggests that algal production systems represent a ‘natural’ source to isolate and study microorganisms that can either benefit or harm algal cultures.

Year-long performance assessment of an on-site pilot scale (100 L) photobioreactor on nutrient recovery and pathogen removal from urban wastewater using native microalgal consortium

The study was carried out as part of the Indo-Dutch collaboration project to ascertain the efficacy of the algal system for the treatment of urban wastewater. The study was done at Barapullah drain in New Delhi, using a pilot-scale (100 L) bubble column microalgae photobioreactor (PBR). The year-long study was intended to find the impact of seasonality coupled with varying hydraulic retention times (HRTs) on the PBR performance in terms of nutrient recovery, microbial contamination reduction, biomass productivity, and theoretical biomethane potential.To begin with, native microalgae consortium was enriched and cultivated in PBR directly on the Barapullah drain wastewater at the drain site. After achieving maximum recovery of nutrients in the batch mode, the PBR was operated in continuous mode at HRTs ranging from 1 to 3 days during summer, while 2–3 days during monsoon, autumn, and winter. The maximum and minimum biomass productivity obtained was 260 mg L−1 d−1 at the HRT of 1 day during summer and 77 mg L−1 d−1 at the HRT of 2 days during winter. At peak overall PBR performance at HRT of 2 days, the nutrient removal rate was 37.2 ± 6.2 mgCOD L−1 d−1, 39.3 ± 6 mgN L−1 d−1, and 4.7 ± 0.7 mgP L−1 d−1. Nearly 5 log removal of total and faecal coliform was obtained during summer and monsoon. However, the overall performance reduced during winters. The natural sedimentation of grown biomass achieved 81–95% of biomass settling at different HRTs. The areal footprint of the PBR is 1.42 m2 KLD−1, which was significantly lower than other pilot-scale microalgal wastewater treatment technologies. The obtained results at this lower HRT (2 days) even under non-optimized process parameters represent vital improvements over earlier reports with significantly higher HRTs. Results thus highlight the feasibility and scalability of the technology.

Feedback mechanisms stabilise degraded turf algal systems at a CO2 seep site

Human activities are rapidly changing the structure and function of coastal marine ecosystems. Large-scale replacement of kelp forests and coral reefs with turf algal mats is resulting in homogenous habitats that have less ecological and human value. Ocean acidification has strong potential to substantially favour turf algae growth, which led us to examine the mechanisms that stabilise turf algal states. Here we show that ocean acidification promotes turf algae over corals and macroalgae, mediating new habitat conditions that create stabilising feedback loops (altered physicochemical environment and microbial community, and an inhibition of recruitment) capable of locking turf systems in place. Such feedbacks help explain why degraded coastal habitats persist after being initially pushed past the tipping point by global and local anthropogenic stressors. An understanding of the mechanisms that stabilise degraded coastal habitats can be incorporated into adaptive management to better protect the contribution of coastal systems to human wellbeing.

Meta-Analytic Review on Third-Generation Biodiesel

Microalgal biodiesel is technically viable to power diesel engines. This third-generation biofuel has great performance of combustion and can reduce emission of greenhouse gases into the atmosphere. However, its production is currently very expensive, relative to petrochemical diesel. Development and implementation of strategies to optimize productivity and quality of biomass and thus ensure this future-proof biofuel is economically feasible to fabricate and competitive with diesel oil on an industrial scale is challenging. This meta-analytic overview documents the diversity of fastest-growing, oil-accumulating microalgae; performance of cultures and systems; strategies for inducing lipids; and quality and economics of microalgal biodiesel. The microalgae, Neochloris oleoabundans, Scenedesmus obliquus, Desmodesmus sp., and Micractinium sp., are hyperaccumulators of lipids. The genre, Micractinium sp., is a thermophile, and thus it can resist hydrothermal streams. Complementarily, it is the fastest to grow and the most productive in both biomass and biodiesel. This should be of great importance to roll-out sustainable, high-performance algal systems in marginal lands in tropical zones, where the heat often makes the planning and management of projects difficult and expensive. Heat shock, nutritional starvation, and photoperiod are the most effective algae-specific strategies for inducing mechanisms for lipogenesis in Ankistrodesmus dimorphus, Chlorella vulgaris and Leptolyngbya sp., Cylindrotheca closterium and N. oleoabundans, and Amphora subtropica and Dunaliella sp., respectively. Rhodococcus sp. produces a significant amount of biomass at very low cost, relative to diesel oil. The concept of synergistically co-culturing microalgae with this photosynthetically active bacterium may be an option to save the producer the expenditures and uncertainties of third-generation biodiesel.

IoT-based Closed Algal Cultivation System with Vision System for Cell Count through ImageJ via Raspberry Pi

Spirulina platensis and other microalgae are now being considered in the different fields of research. It is due to the former’s endless potential let alone, its high protein content. That is why, a stable demand of microalga production is now necessary. To achieve a high-protein spirulina, its cultivation using closed algal cultivation requires monitoring and maintenance of the bio-environmental factors and parameters affecting its growth to provide a stable and efficient production of microalgae. Meanwhile, laboratories that culture spirulina determine its cell count through manually counting the cells under a microscope – a tedious work. This establishes the need to construct a device that cultivates spirulina with maintaining and cell counting capabilities. Thus, the proponents developed a culturing device that has three main systems. The first system is tasked to maintain the bio-environmental parameters, such as the pH level, temperature, and light. The second system on the other hand speaks of the cell counting system through ImageJ’s Image Processing. This system verifies the cell count and growth through counting the filaments of the spirulina. Lastly, a corresponding Android application, which was developed using Firebase and Android Studio, displays real-time values of the culture’s parameter. Results show that the device was able to stabilize its parameters. Also, red LEDs exhibited 28.43% higher approximate cell count than red-blue LEDs. With this, the quality of the Spirulina that was produced throughout the study was improved. Lastly, the use of ImageJ’s image processing feature showed no significant difference with manual counting. It also releases the results multiple times faster than the manual counting. Thus, being a better alternative to manual cell counting.

Separable roles for RanGTP in nuclear and ciliary trafficking of a kinesin-2 subunit

Kinesin is part of the microtubule-binding motor protein superfamily, which serves important roles in cell division and intraorganellar transport. The heterotrimeric kinesin-2, consisting of the heterodimeric motor subunits, kinesin family member 3A/3B (KIF3A/3B), and kinesin-associated protein 3 (KAP3), is highly conserved across species from the unicellular eukaryote Chlamydomonas to humans. It plays diverse roles in cargo transport including anterograde (base to tip) trafficking in cilia. However, the molecular determinants mediating trafficking of heterotrimeric kinesin-2 itself are poorly understood. It has been previously suggested that ciliary transport is analogous to nuclear transport mechanisms. Using Chlamydomonas and human telomerase reverse transcriptase-retinal pigment epithelial cell line, we show that RanGTP, a small GTPase that dictates nuclear transport, regulates ciliary trafficking of KAP3, a key component for functional kinesin-2. We found that the armadillo-repeat region 6 to 9 (ARM6–9) of KAP3, required for its nuclear translocation, is also necessary and sufficient for its targeting to the ciliary base. Given that KAP3 is essential for cilium formation and there are the emerging roles for RanGTP/importin β in ciliary protein targeting, we further investigated the effect of RanGTP in cilium formation and maintenance. We found that precise control of RanGTP levels, revealed by different Ran mutants, is crucial for cilium formation and maintenance. Most importantly, we were able to provide orthogonal support in an algal model system that segregates RanGTP regulation of ciliary protein trafficking from its nuclear roles. Our work provides important support for the model that nuclear import mechanisms have been co-opted for independent roles in ciliary import.

Immobilization altering the growth behavior, ammonium uptake and amino acid synthesis of Chlorella vulgaris at different concentrations of carbon and nitrogen

Nitrogen recycling by microalgae has aroused considerable attention. In this study, immobilized Chlorellavulgaris with 5-day mixotrophic cultivation to recover ammonium (NH4+-N) were systematically investigated under various sodium acetate (CH3COONa) and ammonium chloride (NH4Cl) concentrations, and evaluated by comparison with suspended cells. The results revealed that, unlike suspended cells, NH4+-N uptake by immobilized cells was not in direct proportion to chemical oxygen demand (COD) concentrations. The immobilized cells to NH4+-N uptake was all inferior to that of suspended cells, presenting the maximum rate of 68.92% in group of 30 mg/L NH4+-N and 200 mg/L COD. Free amino acids in immobilized cells such as glutamate (Glu), arginine (Arg), proline (Pro) and leucine (Leu) were more sensitive to NH4+-N assimilation, as higher values observed by suspended cells. Low carbon-nitrogen (C/N) ratio showed remarkable benefits to amino acid synthesis. These results could provide a reference for manipulating the algal system and biomass accumulation.

Integration of a side-stream microalgae process into a municipal wastewater treatment plant: A life cycle analysis

This study investigates the environmental improvements associated to the integration of a microalgae unit as a side-stream process within an existing municipal wastewater treatment facility in northern Italy. Microalgae are fed on the centrate from sludge dewatering, rich in nutrients, and on the CO2 in the flue-gas of the combined heat and power unit. The produced biomass is recirculated upflow the water line where it settles and undergoes anaerobic digestion generating extra biogas. A life cycle assessment was performed collecting primary data from an algal pilot-scale plant installed at the facility. Fifteen environmental indicators were evaluated. Compared to the baseline wastewater treatment, the new algal configuration allows an improvement for 7 out of 15 indicators mainly thanks to the electricity savings in the facility. Some recommendations are provided to improve the performance of the algal system in the scaling up.

Optimization of the integrated power and desalination plant with algal cultivation system compromising the energy-water-environment nexus

This article examines the exhaust waste heat recovery potential of a microturbine (MT) for seawater desalination using an organic Rankine cycle (ORC). Waste heat from microturbine is exploited using organic Rankine cycle (ORC) and the power generated is delivered to the reverse osmosis (RO) plant. The brine of the reverse osmosis plant is sent to a membrane distillation (MD) plant for further treatment after preheating using the excess heat from the turbine. Also, biological capture of CO2 through cultivation of microalgae has been considered by using flue gases from the microturbine. Plant integration is performed on the basis of the energy-water-environment nexus concept. In this regard, a multi-objective optimization approach is implemented in this work considering economic and environmental points of views. The first objective function is to maximize the annual profit of the system. The second objective function is an environmental index which is defined as the CO2 emission per desalinated water production. Minimization of this index is considered as the second objective function. The results showed that the proposed integrated ORC-RO-MD-CO2 capture plant can considerably improve the system both economically and environmentally.

Deconcentration of Chromium Contained in Wastewater Using a Bacteria and Microalgae Consortia with a High Rate Algal Reactor System

Deconcentration of Chromium Contained in Wastewater Using a Bacteria and Microalgae Consortia with a High Rate Algal Reactor System

Artificial neural network and techno-economic estimation with algae-based tertiary wastewater treatment

In this study, secondary-treated (ST) wastewater effluents supplemented with different nutrient sources were employed for microalgae cultivation in outdoor pilot-scale pools operated under natural environmental conditions. The BG11-supplemented wastewater showed a high algal biomass concentration = 0.79 ± 0.04 g/L, with NO3−, NH4+, and PO43− removal efficiencies = 83.20 ± 2.90 %, ≈ 100 %, and 93.50 ± 3.28 %, respectively. The corresponding lipid, protein, and carbohydrate contents of microalgae were 25.60 ± 0.80 %, 29.00 ± 0.88 %, and 18.40 ± 1.00 % w/w dry cell weight (DCW) basis, respectively. The ranges of protein and carbohydrate contents of lipid-extracted biomass were 25–40 % and 17–23 %, respectively. A three-layer feed-forward back-propagation artificial neural network (ANN) was used to predict the microalgae DCW, based on six inputs, i.e., temperature, pH, dissolved oxygen (DO), electrical conductivity (EC), NO3−, and PO43-. The optimized ANN architecture (6–10 – 1), with the Levenberg-Marquardt training algorithm, achieved the highest predictive performance (R2: 0.983). Based on the ANN sensitivity analysis, the environmental factor’s relative importance arranged as NO3− > PO43- > pH ≈ DO > temperature > EC. The nutrient removal ability and biochemical composition of microalgae were expressed regarding capital and operational costs, and profits. The payback period of the wastewater-based algal cultivation system was shorter than the project’s lifetime, implying a sustainable and feasible application.

A real time data driven algal bloom risk forecast system for mariculture management

In eutrophic coastal waters, harmful algal blooms (HAB) often occur and present challenges to environmental and fisheries management. Despite decades of research on HAB early warning systems, the field validation of algal bloom forecast models have received scant attention. We propose a daily algal bloom risk forecast system based on: (i) a vertical stability theory verified against 191 past algal bloom events; and (ii) a data-driven artificial neural network (ANN) model that assimilates high frequency data to predict sea surface temperature (SST), vertical temperature and salinity differential with an accuracy of 0.35oC, 0.51oC, and 0.58 psu respectively. The model does not rely on past chlorophyll measurements and has been validated against extensive field data. Operational forecasts are illustrated for representative algal bloom events at a marine fish farm in Tolo Harbour, Hong Kong. The robust model can assist with traditional onsite monitoring as well as artificial-intelligence (AI) based methods.

Impact of bovine serum albumin – A protein corona on toxicity of ZnO NPs in environmental model systems of plant, bacteria, algae and crustaceans

Zinc oxide nanoparticles (ZnO NPs) are widely applied in industrial, household and medical areas that lead to its discharge and accumulation in ecosystem. Here, the toxic effect of ZnO NPs in presence and absence of bovine serum albumin (BSA) was analyzed. The difference in toxicity of bare ZnO and BSA interacted ZnO was studied with different environmental models. P. aeruginosa and S. aureus were used as model bacterial systems. Toxicity against bacteria was determined by employing plate count method. C. pyrenoidsa was used as algal system for evaluating toxicity and it was determined by chlorophyll estimation assay. Daphnia sp. was chosen as crustacean system model. A. cepa root cells were chosen as plant model. ZnO NPs increased the ROS formation, lipid peroxidation and oxidative stress and it reduced in the presence of BSA. The cytotoxicity, chromosomal aberrations and micronuclei (MN) index of A. cepa were increased after ZnO NPs treatment. Same time the toxic effect was decreased in case of BSA coated ZnO NPs. The NPs toxic potential on the organisms decreased in the order of P. aeruginosa (LC50–0.092 mg/L) > S. aureus (LC50–0.33 mg/L) > Daphnia sp (LC50–0.35 mg/L) > C. pyrenoidosa (LC50–8.17 mg/L). LC50 in presence of BSA was determined to be 18.45, 26.24, 17.27 and 53.97 mg/L for P. aeruginosa, S. aureus, Daphnia sp and C. pyrenoidosa respectively. Therefore, the report suggests that BSA stabilized ZnO NPs could be more amenable towards applications in biotechnology and bioengineering.

Mixotrophic algal system for centrate treatment and resource recovery

In traditional activated sludge-based wastewater treatment plants equipped with anaerobic digesters, the nutrient-rich centrate from the digester is typically recirculated to the headworks of the plant exerting a parasitic load. As an alternative, mixotrophic algal cultivation in a blend of the centrate and primary effluent is proposed to yield energy- and nutrient-rich biomass from which, liquid biofuel and fertilizers could be recovered. Core components in the proposed sewage treatment and resource recovery (STaRR) system include i) algal sewage treatment/biomass cultivation; ii) hydrothermal liquefaction of algal biomass for energy recovery, and iii) recovery of struvite and concentrated ammonia from the hydrothermal liquefaction byproducts. Results from a 700 l pilot-scale STaRR system run with four different blends of centrate and primary effluent are presented to validate the proposed approach. A 20: 80 centrate-to-primary effluent blend enabled discharge standards for ammoniacal‑nitrogen, phosphate phosphorus, and biochemical oxygen demand to be met in <7 days; volumetric removal rates at this blending ratio were 4.0 mg/l-d, 0.70 mg/l-d and, 10.50 mg/l-d, respectively. Hydrothermal liquefaction of the resulting biomass (20% solids content, 350 °C, and 60 min holding time) yielded 77.5 g light bio-crude oil and 108.0 g heavy bio-crude oil per kg of dry algae. It is estimated that the STaRR system can produce 6.75 kg of struvite and 3.42 kg of concentrated ammoniacal nitrogen per 100 m3 of blended wastewater.

Agricultural fertiliser from brewery effluent – the recovery of nutrients from the biomass of activated sludge and high rate algal pond treatment systems

Abstract The disposal of waste biomass generated from biological wastewater treatment plants is a costly process and poses environmental threats to the receiving environment. This study aimed to determine the suitability of algae and waste activated sludge (WAS) produced from a brewery effluent treatment system as a fertiliser in agriculture. The change in soil characteristics and the growth of a crop fertilised with algae or WAS was compared with a conventional inorganic fertiliser. Swiss chard plants (Beta vulgaris) fertilised with anaerobically digested (AD) algae or WAS had a significantly higher mean biweekly yield (5.08 ± 0.73 kg/m2) when compared with the inorganic fertiliser control (3.45 ± 0.89 kg/m2; p &amp;lt; 0.0001). No difference was observed in the soil's physical fertility when algae or WAS were applied to the soil (p &amp;gt; 0.05). The nitrogen applied to the soil from algae and WAS biomass appeared to leach out of the soil less than the nitrogen supplied by inorganic fertilisers. The application of WAS or algae on soil increased the soil's sodium concentration and sodium absorption ratio from 774.80 ± 13.66 mg/kg to 952.17 ± 34.89 mg/kg and 2.91 ± 0.04 to 3.53 ± 0.13, respectively. Regulations on the application of algae or WAS on agricultural soils should be altered to consider the limit values for sodium.

Carbon limitation in hypereutrophic, periphytic algal wastewater treatment systems.

Global eutrophication degrades water quality in freshwater ecosystems and limits the availability of freshwater for human consumption. While current wastewater treatment facilities (WWTF) remove pathogens and pollutants, many US WWTF continue to discharge nutrients that contribute to eutrophication. Traditional nutrient removal technologies can effectively reduce eutrophication risk, but can have unintended negative consequences on human and environmental health. Alternatives, such as algae-based treatment systems, improve the sustainability of the nutrient recovery process by producing biomass that can be converted to biofuel. However, research is needed to increase the productivity of algal treatment systems to improve their economic viability. Because algae in wastewater treatment systems are grown in wastewater rich in nutrients, the algae could become limited by dissolved inorganic carbon. This hypothesis was tested in 1.2 m long recirculating floways (n = 8 for each treatment/control) by quantifying algal dry mass and wastewater nutrient concentrations in 3 independent experiments: (1) carbon dioxide gas infused vs air infused control; (2) hydrochloric acid acidified vs neutralized solution control vs no chemical addition control; and (3) sodium bicarbonate addition vs no chemical control. Results showed increases in algal biomass after 18 days in wastewater augmented with dissolved inorganic carbon (carbon dioxide or sodium bicarbonate). In contrast, maintaining wastewater at near neutral pH with hydrochloric acid reduced algal productivity relative to controls. Nutrient reductions generally paralleled algal biomass increases except in the bicarbonate addition experiment. These findings provide evidence for the importance of carbon limitation in algal wastewater treatment floways. These results could help explain why carbon dioxide infusions stimulate algae in treatment systems. Furthermore, these results suggest that algae in nutrient enriched, sun-exposed streams (e.g., agricultural ditches or urbanized streams) may become carbon limited during peak periods of productivity. These findings could have important implications for ecosystems undergoing eutrophication as atmospheric carbon dioxide concentrations continue to rise.

Cytotoxicological evaluation of copper oxide nanoparticles on green algae, bacteria and crustacean systems.

Copper oxide (CuO) nanoparticles (NPs) have been utilized in several industries including textile, consumer products, medical, automobiles etc. The discharge of industrial effluents in environment increased the probability of CuO NPs contamination in the ecosystem. The present investigation used CuO NPs to determine the toxic effect on Lyngbya species, fresh water algae isolated from natural pond, bacterial species Pseudomonas aeruginosa and Staphylococcus aureus and a crustacean species Daphnia magna. The NPs average diameter and zeta potential was estimated to be 45 ± 3nm and 29 ± 1.78mV respectively. The results showed that 0.1µg/mL CuO NPs showed the growth inhibition of 47 ± 2% on Lyngbya sp. after 5 days of incubation. The CuO NPs also showed toxic effect to bacterial systems such as P. aeruginosa and S. aureus and crustacean system D. magna. Further, there was an increased lipid peroxidation and generation of reactive oxygen species (ROS) in algal cells observed up on NPs exposure. The exposure of NPs suppressed the antioxidant defense system. The amount of glutathione was reduced after the exposure of NPs. The study suggested the role of ROS in toxicity of algal and bacterial systems. The present study pointed out the potent toxicity of CuO NPs to the organisms present in the aquatic environment.