Microalgae-bacteria Consortium Research Articles

Removal of Nitrogen, Phosphorus, Organic Matter, and Heavy Metals from Pig-Farming Wastewater Using a Microalgae-Bacteria Consortium.

Wastewater generated by the pork industry urgently requires the implementation of low-cost, high-benefit, and efficient treatment systems. Accordingly, a microalgae-bacteria consortia-based treatment system is proposed for the removal of contaminants released, by the pork-producing industry, in swine wastewater. In this study, different inoculum concentrations of the microalgae-bacteria consortium were tested to document variation in the removal of nutrients from the wastewater. At varying concentrations, it was efficient and did not present a significant difference in the removal kinetics. The treatment with the greatest amount of inoculum removed close to 87% of total nitrogen, approximately 70% of orthophosphate, and 77% of chemical oxygen demand. Removals of 84% iron, 44% copper, and 48% manganese were also obtained. These results demonstrate that microalgae-bacteria consortia are an economically viable and environmentally desirable option for the efficient treatment of wastewater from the pork industry.

Removal of sulfamethoxazole in an algal-bacterial membrane aerated biofilm reactor: Microbial responses and antibiotic resistance genes

Antibiotics are frequently detected in wastewater, but often are poorly removed in conventional wastewater treatment processes. Combining microalgal and nitrifying bacterial processes may provide synergistic removal of antibiotics and ammonium. In this research, we studied the removal of the antibiotic sulfamethoxazole (SMX) in two different reactors: a conventional nitrifying bacterial membrane aerated biofilm reactor (bMABR) and algal-bacterial membrane aerated biofilm reactor (abMABR) systems. We investigated the synergistic removal of antibiotics and ammonium, antioxidant activity, microbial communities, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and their potential hosts. Our findings show that the abMABR maintained a high sulfamethoxazole (SMX) removal efficiency, with a minimum of 44.6 % and a maximum of 75.8 %, despite SMX inhibition, it maintained a consistent 25.0 % ammonium removal efficiency compared to the bMABR. Through a production of extracellular polymeric substances (EPS) with increased proteins/polysaccharides (PN/PS), the abMABR possibly allowed the microalgae-bacteria consortium to protect the bacteria from SMX inactivation. The activity of antioxidant enzymes caused by SMX was reduced by 62.1–98.5 % in the abMABR compared to the bMABR. Metagenomic analysis revealed that the relative abundance of Methylophilus, Pseudoxanthomonas, and Acidovorax in the abMABR exhibited a significant positive correlation with SMX exposure and reduced nitrate concentrations and SMX removal. Sulfonamide ARGs (sul1 and sul2) appeared to be primarily responsible for defense against SMX stress, and Hyphomicrobium and Nitrosomonas were the key carriers of ARGs. This study demonstrated that the abMABR system has great potential for removing SMX and reducing the environmental risks of ARGs.

Development and performance of microalgae-based symbiotic systems for high-strength chemical oxygen demand wastewater treatment from the sugar mills

Agricultural and agro-industrial activities have risen exponentially to meet the ever-growing demand for food, energy, and other important resources. High freshwater consumption occurs in these sectors and is discharged as effluent containing excessive organic loads that require treatment. In this study, microalgal, bacterial, and fungal (yeast) isolates native to the sugar industry effluent were screened for effective chemical oxygen demand (COD) removal from wastewater when co-cultured. The microalgae-bacteria consortium (MBC) comprised Chlorella sorokiniana A7 and three bacterial strains including Rhodococcus sp. B009, Bacillus sp. B010, and B013; whilst the microalgae-yeast consortium (MYC) consisted of Chlorella sorokiniana A7 and Saccharomyces cerevisiae Y2. When the Chlorella sorokiniana-based symbiotic systems were characterized in sugar industry wastewater, excellent COD removal efficiencies were achieved compared to the axenic Chlorella sorokiniana A7. The COD removal efficiencies were 86 %, and 71 % after 96 h of cultivation for MBC, and MYC, respectively. After 168 h of cultivation in wastewater, ≥90 % of COD removal efficiency was observed in both MBC and MYC systems. The MYC also showed improved chlorophyll-a content, photosynthesis, and respiration in Chlorella sorokiniana A7. This study has demonstrated the efficiency of Chlorella sorokiniana-based consortium systems that could be used as eco-friendly and sustainable bioremediation tools for high-strength COD wastewater streams. An insight into mechanisms of interactions between Chlorella sp., and co-cultured microbial strains grown in sugar industry wastewater still needs further studies.

Effect of Light and Dark Regimes on Cultivation of Microalgae-Bacteria Consortium for Oilfield Wastewater Treatment

Effect of Light and Dark Regimes on Cultivation of Microalgae-Bacteria Consortium for Oilfield Wastewater Treatment

Effect of C:N ratio on treatment of mixed industrial-domestic wastewater by microalgae-bacteria consortium

Effect of C:N ratio on treatment of mixed industrial-domestic wastewater by microalgae-bacteria consortium

Development of Microalgae-Bacteria Consortium for the Treatment of Domestic Waste Water

Development of Microalgae-Bacteria Consortium for the Treatment of Domestic Waste Water

Development of alginate beads loaded with bioactive ingredients from Chlorella vulgaris cultivated in food industry wastewaters

Microalgae are increasingly recognized for their potential in the food sector due to their rapid growth and rich content in proteins, carbohydrates, and pigments. The extraction of pigments from microalgal biomass holds promise for their utilization as natural colorants and antioxidants. To address the economic challenges associated with microalgae cultivation, particularly high nutrient costs, this study focused on cultivating Chlorella vulgaris in a mixture of food industry wastewaters (brewery wastewater, expired orange juice and cheese whey). This resulted in a microalgae-bacteria consortium with a concentration of 2.2 g·L−1 dry weight after 5 days of cultivation. The wastewater bioremediation ranged between 23 and 77 %, and the produced microalgae biomass contained 21.68 ppm lutein, 36.47 ppm a-chlorophyll and 11.19 ppm b-chlorophyll. The extraction process employed a solvent screening strategy with food industry-accepted solvents used to extract high-value compounds efficiently. Ethanol was the most effective solvent, outperforming acetone, ethyl acetate, and hexane. An upscaled extraction process was conducted using 10 g lyophilized microalgae. After ethanol evaporation, the microalgal extract was re-diluted in sunflower oil and encapsulated in alginate beads, achieving an encapsulation yield of 93.3 %. Lutein, identified as one of the main compounds in the extract, exhibited a satisfactory encapsulation efficiency of 55 %. The efficient encapsulation of the microalgae components in alginate beads was verified by the alteration of the colorimetric parameters of these alginate beads compared to those loaded with pure sunflower oil as well as empty beads. These findings highlight the potential of microalgae as a valuable tool for transforming food industry wastewater into high-value products, especially when microalgal extract is encapsulated in alginate beads. This strategy presents substantial prospects for the food industry, merging effective wastewater valorization with biomass production and bioactive compound extraction. It exemplifies a circular bioeconomy, showcasing sustainable resource management and value creation.

Integrating microalgae-based wastewater treatment, biostimulant production, and hydroponic cultivation: a sustainable approach to water management and crop production.

A natural appearing microalgae-bacteria consortium was used to process urban wastewater. The process was done in an 80m2 raceway reactor and the results were compared to an identical reactor operated using freshwater supplemented with commercial fertilisers. The biomass harvesting was done using commercial ultrafiltration membranes to reduce the volume of culture centrifuged. The membrane allowed achieving a biomass concentration of ∼9-10gL-1. The process proposed avoids the use of centrifuges and the drying of the biomass, two of the most energy consuming steps of conventional processes. The specific growth rate in freshwater and the wastewater-based media was estimated as 0.30 ± 0.05 and 0.24 ± 0.02 days-1, respectively (p < 0.05). The maximum concentration reached at the end of the batch phase was 0.96 ± 0.03 and 0.83 ± 0.07gL-1 when the biomass was produced using freshwater and wastewater, respectively (p < 0.05). The total nitrogen removal capacity of the system was on average 1.35gm-2·day-1; nitrogen assimilation into biomass represented 60%-95% of this value. Furthermore, the P-PO4 3- removal capacity of the system varied from 0.15 to 0.68gm-2·day-1. The outlet effluent of the reactor was used as a nutrient source in the hydroponic production of zucchini seedlings, leading to an increase in the root dry weight and the stem diameter compared to the water alone. The produced biomass showed potential for use as feedstock to produce plant biostimulants with positive effects on root development and chlorophyll retention.

Full nitrogen and phosphorus removal in the PASDEBPR system

Photo-activated sludge (PAS) system aims to utilize microalgae to deliver oxygen for bacterial respiration, eliminating the need for external aeration. However, research on the treatment potential of PAS systems in the removal of nutrients is limited. In this context, a research study was devised to evaluate the possibility of developing a microalgae-bacteria consortium to achieve the simultaneous removal of organic carbon, nitrogen, and phosphorus. A successful PAS system capable of removing phosphorus was established at the end of the first phase, with an effluent phosphorus (P) concentration of 1.6 mg P L−1. In the subsequent stage, during the introduction of the nitrification-denitrification process, the system lost stability and deteriorated. Interestingly the system recovered via the sparging of nitrogen gas reaching effluent concentrations of 1.22 mg P L−1 and 0.88 mg N L−1. Thus, the system was capable of removing phosphorus and nitrogen via biological means without the need for external aeration. It is hypothesized that the inhibition caused was due to the production of a gaseous compound during the nitrification/denitrification process.

Influence of a static magnetic field on the photosynthetic apparatus, cell division, and biomass composition of a Chlorella microalgae-bacteria consortium

Influence of a static magnetic field on the photosynthetic apparatus, cell division, and biomass composition of a Chlorella microalgae-bacteria consortium

Piggery wastewater treatment with a Chlorella microalgae-bacteria consortium and static magnetic field

Wastewater discharges into the environment without adequate treatment is a problem still unresolved. That is why alternative technologies, such as applying static magnetic field (SMF), are currently being sought. The objective of this research was to evaluate the effect of a 47.23 mT SMF on the removal of nitrogen (N), phosphorus (P), and the growth of a Chlorella microalgae-bacteria consortium grown in piggery wastewater under different photoperiods. SMF application increased culture productivity, with maximum values of 0.030 g/ Ld−1 in cultures exposed to SMF in a 16:8 h light/dark photoperiod and 0.038 g/ Ld−1 for the 24:0 h light/dark photoperiod. Furthermore, SMF application increased the microorganisms' photosynthetic efficiency (QY), regardless of the photoperiod used. No significant differences were observed on day 21 regarding nutrient removal between the treated and control cultures. Removal percentages of 93.41 % N and 95.56 % P were obtained for the cultures exposed to SMF in the 16:8 h light/dark photoperiod, and 94.78 % N and 95.59 % P for cultures exposed to SMF during the 24:0 h light/dark photoperiod. In general, SMF acts mainly on the growth of microorganisms.

Microalgae-based domestic wastewater treatment: a review of biological aspects, bioremediation potential, and biomass production with biotechnological high-value.

This review aims to perform an updated bibliographical survey on the cultivation of microalgae in domestic wastewater with a focus on biotechnological aspects. It was verified that the largest number of researches developed was about cultures in microalgae-bacteria consortium and mixed cultures of microalgae, followed by researches referring to the species Chlorella vulgaris and to the family Scenedesmaceae. According to published studies, these microorganisms are efficient in the biological treatment of domestic wastewater, as well as in the production of high value-added biomass, as they are capable of biosorbing the organic and inorganic compounds present in the culture medium, thus generating cells with high levels of lipids, proteins, and carbohydrates. These compounds are of great importance for different industry sectors, such as pharmaceuticals, food, and also for agriculture and aquaculture. In addition, biomolecules produced by microalgae can be extracted for several biotechnological applications; however, most studies focus on the production of biofuels, with biodiesel being the main one. There are also other emerging applications that still require more in-depth research, such as the use of biomass as a biofertilizer and biostimulant in the production of bioplastic. Therefore, it is concluded that the cultivation of microalgae in domestic wastewater is a sustainable way to promote effluent bioremediation and produce valuable biomass for the biobased industry, contributing to the development of technology for the green economy.

Microalgae-bacteria consortia for the treatment of raw dairy manure wastewater using a novel two-stage process: Process optimization and bacterial community analysis

The major objective of this study was to develop a functional microalgae-bacteria consortium for the treatment of dairy manure wastewater (DMW). Chlorella sorokiniana AK-1 was selected as the proficient microalgal strain for treating unsterilized DMW. AK-1 was directly grown in 50% raw DMW, and the addition of an acclimated mixed bacterial culture enriched from dairy manure improved treatment efficiency. Culture conditions for DMW treatment using the AK-1 mixed bacterial consortium were optimized as follows: 50% raw DMW, 0.4 g/L mixed bacterial inoculum on day 1, followed by 0.1 g/L AK-1 inoculum on day 3, and further incubation for 3 days. The achieved removal efficiencies for COD, BOD, TN, NH3-N, and TP were 84.3%, 97.8%, 90.2%, 99.1%, and 100%, respectively. Bacterial 16S rDNA sequencing was conducted to analyze the shift in the bacterial community during wastewater treatment. In DMW, Firmicutes emerged as the dominant phylum, whereas Proteobacteria took over after microalgal inoculation. Additionally, Actinobacteria and Bacteroidetes were consistently present in all samples. Interestingly, Patescibacteria and Planctomycetes were found in varying proportions. At the species level, the predominant bacteria identified during the treatment process were Rhizobiaceae, Sericytochromatia_unclassified, Pirellula_sp, Owenweeksia, Devosia_unclassified, Acinetobacter_towneri, and Acinetobacter_unclassified. Despite the significant diversity of the microbial community among the different processes, optimal microalgal biomass production and maximum nutrient removal efficiencies were achieved using this designer microalgae-bacteria consortium.

Illuminated septic tank – A microalgae assisted onsite wastewater treatment system

To reduce the anthropogenic nutrient loading into natural waterways, onsite wastewater treatment is essential for households without access to municipal sewer systems. However, many conventional septic tanks significantly underperform the centralized wastewater treatment. In the present study, a novel illuminated septic tank inoculated with the consortium of microalga Chlorella vulgaris and aerobic bacteria was developed by modifying the conventional configuration. The inclusion of microalgae facilitated aeration inside the septic tank through photosynthetic oxygen evolution, and the microalgae-bacteria consortium enhanced the wastewater treatment performance. With the operation at 15 ℃ and a hydraulic retention time of 2.5 days, the lab-scale algae-assisted septic tank significantly decreased the concentrations of ammonium-nitrogen (NH4+-N), soluble phosphorus (P), total P, and total chemical oxygen demand by 54%, 65.2%, 78.5%, and 90.7% in the discharged effluent, respectively (p < 0.05), whereas the conventional septic tank without microalgae did not exhibit any treatment of NH4+-N or soluble P and the total P removal efficiency was lower by 50%. Meanwhile, the photosynthetic activity of microalgae altered the gas composition in the tank headspace by consuming carbon dioxide, emitting oxygen, and inhibiting the evolution of methane, which further benefited the aeration requirement and contributed to the mitigation of greenhouse gas emissions from septic systems.

Process for nutrient recycling from intensive aquaculture through microalgae-bacteria consortium

This work studies a biological process based on a microalgae-bacteria consortium for recycling nutrients in a recirculating aquaculture system (RAS) implanted in an intensive marine aquaculture farm. Additionally, some techniques were used for microalgae biomass harvesting and tested the effectiveness of filtration by a column with multi-layer sand to reduce the solids concentrations in the effluent.The consortium was grown in photobioreactors in batch and semi-continuous operation modes using the solids concentrated stream generated in the RAS system. The semi-continuous operation showed a high percentage of TDN and TDP removal, achieving final concentrations of 1.09 ± 0.02 mg·L−1 and 0.01 ± 0.01 mg·L−1, respectively, while DOC was reduced to 3.87 ± 0.06 mg·L−1. The values of productivity 44 ± 9 mg TSS·L−1 indicated that the studied stream is a suitable culture medium for the growth of the microalgae-bacteria consortium.A combination of harvesting techniques was studied, coagulation-flocculation-settling and coagulation-flocculation-flotation. The first step was to optimise the dose of FeCl3 through the coagulation-flocculation test to pre-concentrate the biomass generated, achieving an optimal dose of 0.106 mg Fe·mg TSS−1. Then, two separation processes were applied to the stream and compared: settling and flotation. The maximum removal efficiency (90.2 ± 0.3 %) was obtained in the settling process, so the coagulation-flocculation-settling was select as the best combination of harvesting techniques.Finally, sand filtration was studied as an effluent refining process to improve solids reduction of the water obtained in the harvesting step resulting in an effluent with 17.18 ± 1.49 mg TSS·L−1.The proposed sequence process is capable of recycling nutrients from an intensive marine aquaculture farm by using these resources via transformation into microalgae biomass and generating quality effluent.

Effects of terminal electron acceptors on the biodegradation of waste motor oil using Chlorella vulgaris-Rhodococcus erythropolis consortia: Kinetic and thermodynamic windows of opportunity analysis

The Chlorella vulgaris-Rhodococcus erythropolis consortia was constructed for the biodegradation of waste motor oil (WMO), combined with thermodynamic calculations and stoichiometric analyses. The microalgae-bacteria consortium was constructed as C. vulgaris: R. erythropolis = 1:1 (biomass, cell/mL), pH = 7, 3 g/L WMO. Under the same condition, the terminal electron acceptors (TEAs) play a crucial role in the WMO biodegradation, which follows Fe3+ >SO42- > none. The biodegradation of WMO fitted well with the first-order kinetic model under experimental temperatures with different TEAs (R2 >0.98). The WMO biodegradation efficiency reached 99.2 % and 97.1 % with Fe3+ and SO42−as TEAs at 37 °C, respectively. Thermodynamic methanogenesis opportunity windows with Fe3+ as TEA are 2.72 times fold as large as those with SO42-. Microorganism metabolism equations demonstrated the viability of anabolism and catabolism on WMO. This work lays the groundwork for the implementation of WMO wastewater bioremediation and supports research into the biochemical process of WMO biotransformation.

Start-up and maintenance of indigenous microalgae-bacteria consortium treating toilet wastewater through partial nitrification and nitrite-type denitrification

Microalgae-bacteria consortium (MBC) provides an alternative to sustainable treatment of human toilet wastewater (TWW) and resource recovery. This study compared the conventional activated sludge system and wastewater indigenous MBC system (IMBC) for nitrogen removal in TWW through the coupled partial nitrification (PN) and nitrite-type denitrification process. PN was firstly established by alternating FA and FNA. Subsequently, the successful PN maintenance with the nitrite accumulation rate ranging between 90.1–95.3% was achieved using two strategies: light irradiation with the appropriate specific light energy density at 0.0188–0.0598 kJ/mg VSS and the timely nitrite-type denitrification with the algae-secreted organics as the carbon source, eventually resulting in the nitrite accumulation rate ranging between 90.1–95.3%. In the IMBC-PN system, bacterial metabolism contributed to 91.5% of nitrogen removal and the rest was through microalgal assimilation. This study offers a sustainable hybrid IMBC-PN process for high NH4+-N strength wastewater treatment (e.g., TWW), which theoretically saves 23.5% aeration and 34.2% carbon source as well as reduces 17.0% sludge production.

Algae-mediated bioremediation of ciprofloxacin through a symbiotic microalgae-bacteria consortium

The ciprofloxacin treating via microalga and its microalgae-bacteria consortium was investigated for discussing the potential application of microalgae-mediated bioremediation. As results, the maximum removal efficiency of ciprofloxacin by pure microalgae and the consortium was 87.5 ± 3.5 % (5 mg/L) and 96.1 ± 0.07 % (40 mg/L), respectively. The consortium enhanced the degradation rate to 0.81 d−1 compared with the pure microalgae (0.27 d−1). To reveal the symbiotic mechanism, extracellular polymeric substances, pigments contents, antioxidant enzymes and symbiotic bacterial community were analyzed. The malondialdehyde content in the pure microalgae (1622.6 ± 38.7 nmol/mg protein) was higher than that in the consortium (298.34 ± 2.4 nmol/mg protein), and there were obvious chlorophyll b accumulations (approximately 90 %) in consortium. In addition, the symbiotic bacteria had a positive effect on microalgal secretion of fulvic acid-type components. As mechanism, symbiotic bacteria improved ciprofloxacin biodegradation by reducing cell damage and secreting fulvic acid. The presence of Phycisphaeraceae and Rhizobiaceae, nitrogen fixation bacteria, in the consortium suggest that improvement of ciprofloxacin biodegradation might be associated with nitrogen co-metabolism as well. Collectively, this work elucidates the mechanism of enhancing elimination of ciprofloxacin via microalgae-bacteria consortium and accelerates development of microalgae-mediated aquaculture tailwater bioremediation.

Future bioenergy source by microalgae–bacteria consortia: a circular economy approach

Future sustainable approach of bioenergy production that uses microalgae–bacteria consortium to produce bioelectricity and biofuel for industrial and daily activities.

Comparative Evaluation of Pyrolysis and Hydrothermal Liquefaction for Obtaining Biofuel from a Sustainable Consortium of Microalgae Arthrospira platensis with Heterotrophic Bacteria

This article presents a comparative evaluation of pyrolysis and hydrothermal liquefaction (HTL) for obtaining biofuel from microalgal biomass (MAB). The research was carried out using biomass of a stable microalgae-bacteria consortium based on Arthrospira platensis. A. platensis was chosen because of its simple cultivation and harvesting. Pyrolysis was carried out at temperatures of 300, 400, 500, and 600 °C with a constant rate of temperature change of 10 °C/min; HTL was carried out at temperatures of 270, 300, and 330 °C. The bio-oil yield obtained by HTL (38.8–45.7%) was significantly higher than that of pyrolysis (up to 21.9%). At the same time, the bio-coal yields using both technologies were almost the same—about 27%. Biochar (bio-coal) can be considered as an alternative strategy for CO2 absorption and subsequent storage since it is 90% geologically stabilized carbon.