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Article

Poultry Slaughterhouse Wastewater Treatment by Green Algae: An Eco-Friendly Restorative Process

by
Elvira E. Ziganshina
*,
Ksenia A. Yureva
and
Ayrat M. Ziganshin
*
Department of Microbiology, Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 420008 Kazan, Republic of Tatarstan, Russia
*
Authors to whom correspondence should be addressed.
Environments 2025, 12(9), 331; https://doi.org/10.3390/environments12090331
Submission received: 8 August 2025 / Revised: 4 September 2025 / Accepted: 11 September 2025 / Published: 18 September 2025
(This article belongs to the Special Issue Advances in Wastewater Bio-Management: Microbial Community Relationships, Monitoring and Assessment)
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Abstract

Poultry slaughterhouse wastewater (PSW) affects environmental and economic issues, and the introduction of modern treatment technologies, including microalgae-based ones, is strictly necessary. In this study, bioremediation of unsterilized PSW by several algal representatives of the genera Chlorella, Tetradesmus, Desmodesmus, and Neochloris was investigated. All microalgae grew in original wastewater, and the elevated N, P, and S levels in PSW allowed the microalgae to increase the biomass yield (from 2.44–3.15 to 2.73–4.42 g L−1). Modification of PSW for cultivation of microalgae made it possible to obtain biomass with a high content of valuable metabolites. The highest protein content was observed in cells of cultures of Chlorella sorokiniana and Neochloris sp. (26% and 33% of the final dry weight, respectively). At the same time, starch and lipids were also accumulated in the algal cells at substantial levels in both original and modified PSW. With the growth of algae, a decrease in the relative abundance of members of Arcobacteraceae and Clostridium, which include pathogens, was also observed. At the same time, PSW contained a variety of bacteria capable of stimulating the growth of microalgae. Thus, integrating microalgae into the treatment of PSW will reduce the negative impact of such wastewaters on the environment and improve the sanitary indicators.

1. Introduction

Today, the poultry industry is experiencing rapid growth due to the growing human population and increasing demand for poultry meat. Poultry farms generate a lot of wastes that can also be used as a source of biogas production [1,2]. Slaughterhouses and meat processing plants are characterized by large volumes of wastewater generated during slaughter, processing, and cleaning (20 L or more per one bird). Such water is considered one of the most polluted types of wastewaters. While solid organic residues are used to produce pet food and fertilizers, the liquid phase requires proper treatment before the final disposal. Poultry slaughterhouse wastewater (PSW) is characterized by high levels of microorganisms and organic loads originating from proteins, fats, feces, carcass remains, and blood. PSW also contains residues of veterinary pharmaceuticals, disinfectants, and cleaning agents. In general, PSW is characterized by high values of biochemical oxygen demand (0.9–5 g L−1), chemical oxygen demand (2.1–12.5 g L−1), and total suspended solids (0.3–8.2 g L−1). Different organic and inorganic compounds in PSW can prompt eutrophication of water bodies [3,4,5,6,7,8].
Among the traditional and combined wastewater treatment processes (chemical coagulation, electrocoagulation, and microbial aerobic/anaerobic treatment), the introduction of microalgae into the wastewater treatment process is an eco-friendly and innovative approach that can minimize the toxicity of wastewater. Research works in the area of treatment of wastewater generated by poultry slaughterhouses demonstrate that satisfactory removal of major pollutants is often difficult to achieve using traditional methods. Moreover, these methods mostly result in the discharge of partially purified water into the environment [3,9]. Interest in the use of microalgae for wastewater treatment is growing due to the low growth requirements of algae, reduced chemical costs, and the absence of sludge formation. Wastewater is a source of different nutrients, making it a suitable growth medium for microalgae. Microalgae, because of their increased growth rate, metabolic plasticity, ability and capability to adapt to several types and compositions of wastewater, are becoming ideal candidates for bioremediation applications. Some representatives of Chlorophyta as well as Cyanobacteria have been noted as promising agents for remediation of different PSW. The participation of algae as part of a microbial consortium has a beneficial effect on the efficiency of bioremediation, since microalgae provide the other microorganisms with the necessary molecular oxygen. They also produce the necessary vitamins for other microorganisms, finally improving the waste treatment process [10].
Microalgae are rarely applied for the treatment of PSW, and they are often used after wastewater pretreatment [11,12]. For example, a new PSW purification method based on precipitation using acid followed by green algae Chlorella vulgaris treatment was developed [12]. The highest algal biomass yield was observed during growth in undiluted wastewater and reached 1.2 g L−1. C. vulgaris was also the subject of another recent study using response surface methodology where high chemical oxygen demand removal efficiency by microalgae from PSW was obtained [13]. Another study investigated the removal of organic compounds, N, and P from slaughterhouse wastewater in a two-stage anoxic-aerobic biological system, and this was followed by UV disinfection [14]. The availability of different essential compounds in wastewaters for microalgae can result in the obtaining of valuable algal biomass, which can be further used in various industries. Key product groups that can be obtained from microalgae include proteins, lipids, carbohydrates, and pigments, each with unique characteristics and applications in areas such as agroindustry and energy [15,16]. Only a few studies have assessed the bioremediation efficiency of individual algal species in parallel with the estimation of the potential of the algal biomass itself after growth in PSW [11,12,17,18]. Moreover, the addition of trace chemical elements (Mo, Zn, Cu, and Mn) for microalgae can be considered an effective strategy for the treatment of PSW [18]. However, there are no studies on the optimization of PSW with important macronutrients such as N, P, and S to produce higher algal biomass yields and finally reduce the cost of the treatment process. Given the seriousness of modern environmental problems, such as the problem of preserving limited freshwater resources [19,20], the production of biomass from microalgae grown in freshwater is not feasible from an industrial point of view, which certainly highlights the relevance and necessity of algae-based biotechnology based on accessible water sources, such as wastewater.
The aim of this study was to identify the cultural and physiological characteristics of a number of freshwater green algae during their growth in non-sterile duck slaughterhouse wastewater in lab-scale photobioreactors. Therefore, two key aspects were evaluated: (i) the purification efficiency of original and modified PSW using various microalgal species and (ii) the potential of the obtained algal biomass for its possible further applications. The addition of extra essential nutrients to the wastewater-based culture medium to increase the yield of high-quality biomass was first tested. In addition, prokaryotic communities were investigated to analyze their influence on the growth of green algae.

2. Materials and Methods

2.1. Wastewater Characteristics

Wastewater samples were obtained from the treatment facilities of a duck slaughterhouse at the Laishevsky District of the Republic of Tatarstan (Russian Federation). The wastewater was collected after the stage of purification from large physical pollutants and fats. The collected wastewater was delivered to the laboratory within an hour in refrigerated transport to minimize chemical and biological changes and was immediately used as a growth medium in the original form (hereinafter PSW). Before cultivation, the wastewater was filtered through several layers of the sterile gauze to remove undissolved solids and microbial aggregates. Then the total solids and volatile solids of the wastewater were measured. Total solids and volatile solids of all water samples were in the range of 0.95–1.41 g L−1 and 0.82–1.21 g L−1, respectively. In addition, experiments were conducted using a growth medium supplemented with N, P, and S sources (hereinafter PSW_mod). NH4Cl, K2HPO4/KH2PO4, and H2SO4 were applied to increase the concentrations of main nutrients in modified wastewater. Within the framework of one experiment (one culture, one type of wastewater), two biological replicates were set up (two bioreactors worked in parallel). For each experiment, a new batch of water was collected. Data on the qualitative characteristics of the investigated wastewater are presented in Table 1. NO2− and NO3− were detected only at very low levels. The research results are expressed as arithmetic means ± standard deviations.

2.2. Microalgae and Experimental Set Up

Based on our previous [21,22] and new studies, the following high-adaptive green algae were selected from our algal collection for cultivation in PSW: Chlorella sorokiniana strain AM-02, Chlorella vulgaris strain SB-M4 (Chlorellales; Chlorellaceae), Tetradesmus obliquus strain EZ-B11, Desmodesmus sp. strain EE-M8 (Sphaeropleales; Scenedesmaceae), and Neochloris sp. EE-K3 (Sphaeropleales; Neochloridaceae). All of the tested cultures are freshwater representatives isolated from rivers and lakes of the Republic of Tatarstan. Standard Bold’s basal medium (BBM with sodium nitrate as a N source) was used to obtain the seed material for each culture. Ampicillin and kanamycin were added to the standard agarized BBM medium to eliminate the possibility of medium contamination by bacteria [21]. Individual colonies were then introduced into 500 mL Erlenmeyer glass flasks with standard BBM medium under sterile conditions and cultured for 5 days in an IKA KS 4000 ic control shaker-incubator (IKA, Staufen, Germany) (at 120 rpm, +28 °C, and constant illumination with an average intensity of 250 μmol photons m−2 s−1). As a light source, one LED phytolamp (ULI-P10-18W/SPFR, Uniel Lighting Co., Hangzhou, China) was applied. The algal biomass was then concentrated by centrifugation at 4000× g for 3 min, and the cells washed with sterile distilled water from the nutrient medium were transferred under sterile conditions to bioreactors containing wastewater.
The studied strains were cultivated in two sterilized 2.8 L BIOSTAT-A plus bioreactors with a working volume of 2.0 L (Sartorius, Göttingen, Germany). These are autoclavable borosilicate glass culture cylindric vessels with a height of 24 cm and an external diameter of 13.5 cm. Uniform illumination of the bioreactors’ surface was maintained using four LED phytolamps (ULI-P10-18W/SPFR, Uniel Lighting Co., Hangzhou, China), which were located on stands on both sides of the bioreactors (two lamps on one side and two lamps on the other side). Illumination was continuous, with a light intensity of 800 μmol photons m−2 s−1 (measured at the vessel surface using a photosynthetically active radiation meter (Apogee Instruments, Logan, UT, USA)). Regardless of the microalga tested, the bioreactors were inoculated with an inoculum estimated to provide an initial optical density of 0.1 measured at 750 nm (OD750nm). During the experiment, the bioreactor systems provided continuous measurement and control of temperature at +28 °C and stirring speed of the growth medium at 100 rpm. pH of the growth medium was measured using an EasyFerm Plus PHI K8 425 electrode (Hamilton, OH, USA) throughout the experiment. Aeration (1.3 L min−1) was achieved using a compressor via a 0.20 µm Midisart 2000 filter (Sartorius, Göttingen, Germany). A SmartTrak 50 thermal mass flow meter (Sierra Instruments, Monterey, CA, USA) was applied to supply CO2. Air and CO2 were mixed and then added to the culture medium by bubbling. Cultivation was performed with a final CO2 supply of 2.0%. When necessary, a sterile 2% Antifoam B (Sigma-Aldrich, St. Louis, MO, USA) was dropped into the reactors to reduce foaming. Values for illuminance, temperature, carbon dioxide flux, and aeration were set based on previously obtained data [21,22,23,24].

2.3. Assessment of Algal Cultures Growth, Nutrient Removal, and Content of Biomass

Algal growth parameters, pigment content, and nutrient consumption by algae were estimated daily. OD750nm was measured daily during the whole experimental period using a Lambda 35 UV/VIS spectrophotometer (PerkinElmer, Singapore) as an indicator of algal culture density. Moreover, the algal cell number was calculated by using a counting chamber. After completion of the experiments, the final biomass was collected by centrifugation at 5000× g for 5 min, washed with distilled water two times, and finally dried at 105 °C for 16 h. The final dry weight (DW) and volatile solids (VS, or ash-free dry weight) were calculated as described previously [23,24]. Biomass productivity (g L−1 day−1) was estimated by dividing the final dry weight by the total number of days (6, 7, or 8 days depending on the experiment) that was necessary to reach the algal stationary growth phase [25]. The total chlorophyll and carotenoid levels at the end of the experiments were determined by using the dimethyl sulfoxide extraction method as described in detail previously [23]. Briefly, 1 mL of the culture medium was centrifuged for 5 min at 10,000× g. The pellet was treated with 1 mL of preheated solvent, incubated for 5 min with shaking at +60 °C in a thermoshaker, and centrifuged for 5 min at 10,000× g. Supernatant absorbance was determined using the Lambda 35 spectrophotometer at 480, 649, and 665 nm. The formulas provided by Wellburn [26] were used to determine the pigment contents. The soluble protein concentration was measured based on the blue G-250 dye-binding Bradford assay using a Bio-Rad protein assay kit (Bio-Rad, Munich, Germany). To quantify the starch content in the microalgal biomass, a commercial total starch determination kit K-TSTA (Megazyme, Wicklow, Ireland) was used. The subsequent steps were performed as was described by us recently [23] and according to the assay’s protocols.
Lipid content in microalgal biomass was estimated by using Folch’s extraction method modified for our purposes. For analysis, 30 mg of dried biomass was placed in a 2 mL metal lysing tube with the two types of beads (0.5 g of 1.0 mm glass beads and one 3 mm metal bead). Then 0.666 mL of chloroform and 0.333 mL of methanol were added to the sample. Cell homogenization was performed in 4 cycles of 30 s at 6.0 m s−1 with a 5 min break between each cycle using the FastPrep-24 homogenizer (MP Biomedicals, Solon, OH, USA). The mixture was transferred into a new tube, and the metal lysing tube was washed twice with a mixture of chloroform and methanol in a volume ratio of 2:1. After centrifugation at 4600× g for 5 min, the supernatant was placed into a new tube, additionally centrifuged, and then transferred into a glass test tube. After that, 20% of the volume of 0.9% aqueous NaCl solution was added, and the resulting mixture was vortexed. After incubation for 10 min, the lower phase containing lipids was carefully collected in a clean test tube. After extraction of lipids, the solvent was removed using a stream of nitrogen gas. All obtained lipid extracts were weighed, and the lipid concentration was estimated. Pigments were excluded from the lipid content calculation. Their exclusion allowed us to report lipid content involved mainly in energy storage and cell structure.
NH4+–N concentrations were estimated using Nessler’s reagent (Sigma-Aldrich, St. Louis, MO, USA) and the Lambda 35 spectrophotometer. Nitrate, nitrite, phosphate, and sulfate concentrations were estimated by using a Dionex ICS-900 ion chromatography system (Thermo Fisher Scientific, Wilmington, NC, USA), an IonPac AG22 (4 × 50 mm) guard column, and an IonPac AS22 (4 × 250 mm) analytical column [27].
All these analyses were measured in triplicate.

2.4. Microbial Community Structure Analysis

The bacterial load in original PSW and after cultivation of microalgae (unmodified treatments) was assessed using conventional microbiology methods. Thus, universal nutrient agar and selective Endo agar were used to enumerate mesophilic-aerobic and facultative anaerobic cultured bacteria (total bacterial count, TBC) and total coliform bacteria (TCB) in wastewater. Microbiological analyses were measured in triplicate for each series of dilution. Individual cultures were subcultured and subsequently cultivated to obtain bacterial biomass for identification.
When identifying pure bacterial cultures of original PSW, the bacterial 16S ribosomal RNA gene was used as a phylogenetic marker. Bacterial 16S rRNA gene fragments were amplified with PCR Master Mix (Thermo Fisher Scientific, Foster City, CA, USA) and primers UniBac27f and Univ1492r. A total of 192 bacterial colonies were selected and then screened in PCR reactions. The prepared library was then analyzed for restriction fragment length polymorphisms with the restriction endonuclease HaeIII (Thermo Fisher Scientific, USA). Restriction patterns were grouped with the Phoretix 1D software (Nonlinear Dynamics, Newcastle upon Tyne, UK). 16S rRNA gene fragments of representative bacterial isolates from each main cluster were sequenced. The 16S rRNA gene sequences were compared to the NCBI database using the Basic Local Alignment Search Tool.
The bacterial community structure in PSW before and after algal growth (at the end of cultivation) was further analyzed by using a MiSeq system (Illumina, San Diego, CA, USA). Wastewater duplicates were pooled (10 mL of each sample), centrifuged at 14,000× g for 10 min, and total DNA was extracted from pellets by using a FastDNA spin kit for soil (MP Biomedical, Solon, OH, USA). For the initial PSW, 10 mL of water samples used for each culture were centrifuged, the pellets were frozen, then pooled, and subjected to total DNA extraction. Sequencing of the 16S rRNA genes was conducted according to Illumina protocols. 16S rRNA gene sequences were grouped into operational taxonomic units, and for taxonomic classification the updated Greengenes2 database was used. Operational taxonomic units representing less than 0.01% of the total reads were excluded from further analysis. All 16S rRNA gene sequences are available upon request.

2.5. Statistical Analysis

Data (DW, VS, biomass productivity, content of pigments, protein, starch, and lipid) for normal distribution were estimated by using the Kolmogorov–Smirnov test. Data were reported as mean ± standard deviation and then statistically compared using the Tukey method and 95% confidence (Minitab software version 20.2.0, State College, PA, USA).

3. Results and Discussion

3.1. Growth in PSW and Bioremediation Capacity

Freshwater green algae C. sorokiniana, C. vulgaris, T. obliquus, Desmodesmus sp., and Neochloris sp. were tested as bioremediation agents of poultry (duck) slaughterhouse wastewater (PSW), the composition of which is given in Table 1. The original PSW was characterized by neutral to slightly alkaline pH values with an ammonium nitrogen concentration in the range of 60–67 mg L−1, relatively low phosphate and sulfate levels, and trace amounts of nitrate and nitrite ions. The lack of oxidized N forms and the presence of ammonium nitrogen as a product of organic nitrogen conversion allow us to note the predominance of facultative anaerobic and anaerobic members in the microbial community of the wastewater treatment system. The introduction of photosynthetic agents in wastewater treatment is driven by the need to develop biotechnology with low operating costs and efficient treatment of major pollutants and to improve the microbiological parameters of water [15,19,28]. Furthermore, separate experiments on wastewater modification were conducted to increase the value of biomass production and the economic feasibility of the treatment (Table 1).
Figure 1 demonstrates the biomass yield obtained during growth of cultures in original and modified PSW. The biomass yield (on average, from 2.44 to 3.15 g L−1) and biomass productivity (on average, from 0.41 to 0.52 g L−1 day−1) allow us to note the suitability of the tested cultures for the treatment of wastewater of original type (Table 2). It should be noted that the presented average biomass productivity does not reflect the actual accumulation of biomass per day, as the cultures were grown under batch conditions. Both species of the genus Chlorella grew better in modified wastewater, which was reflected in the increase in biomass yield in PSW_mod treatments (up to 4.42 g L−1). Neochloris sp. had the lowest growth values in PSW among the tested algae, as evidenced by both the accumulated biomass values (Figure 1; Table 2) and the macronutrient removal values from the growth medium (Figure 2; Table 2). In a recent study performed by Viegas et al. [11], microalgae Chlorella protothecoides, C. vulgaris, and T. obliquus were tested as bioremediation agents for ash-pretreated PSW. Thus, the maximum biomass productivity was observed for T. obliquus and amounted to 0.1 g L−1 day−1 and 0.25 g L−1 day−1 in batch and semi-continuous modes, respectively. In our study, the adaptability and growth ability of all tested algal cultures in original and modified PSW were observed.
When grown in original wastewater, Scenedesmaceae cultures decreased the NH4+ concentration faster than other cultures. As mentioned above, the lowest N removal rates were observed in the experiments with Neochloris sp. (Figure 2). At the same time, modification of the medium significantly changed the picture of bioremediation; namely, it allowed the representatives of Chlorellaceae to successfully utilize NH4+ after 72 h. The applied temperature and pH of the growth medium minimized the conversion of ammonium to free ammonia. We also performed several experiments on the addition of NH4Cl as a source of NH4+ (0.5–1.0 g L−1) to a sterilized K-Na-phosphate buffer (pH 7 and 8). After 2 weeks of abiotic experiments at +28 °C, no significant changes in the level of NH4+ were observed. Furthermore, all microalgae, with the exception of Neochloris sp., completely utilized PO43− and SO42− from the modified medium (Table 2). It should be mentioned that a portion of these elements could also be consumed by bacteria present in wastewater. The processing industry of the agricultural sector makes a greater contribution to the eutrophication of water bodies, which is explained by the high content of nitrogenous compounds and total phosphorus in wastewater. Research that helps close the gaps in the field of microalgae cultivation in wastewater will allow in the future to modernize the operating conditions of purification systems, develop combined purification methods, and make a great contribution to solving the problem of declining water quality [19,28,29,30,31].
On the first day, the pH of the growth medium increased, which is apparently due to the utilization of the acidic components of the wastewater. A decrease in the pH of the medium could be observed after 24 h of cultivation (or after 48 h of Neochloris sp. cultivation in PSW_mod), which was associated with the active consumption of ammonium (due to the release of H+ during ammonium consumption) (Figure 3). The change in the pH level in original PSW was not so rapid and remained at the level of slightly alkaline values, while in PSW_mod treatments, with a higher initial level of NH4+–N, the pH gradually decreased towards the end of cultivation. In general, these wastewaters have good buffering capacity, meaning that there will be no need for increased costs associated with maintaining pH under industrial conditions.
As can be seen in Table 2, both representatives of the genus Chlorella, C. sorokiniana and C. vulgaris, showed increases in ash-free dry weight in response to elevated concentrations of N, P, and S (4.13 ± 0.19 and 4.25 ± 0.11 g L−1, respectively). Representatives of the family Scenedesmaceae also responded with an increase in biomass in response to the modification of the growth medium (the increase in biomass was about 1 g L−1). It is fair to note that the modification of the growth medium allowed all microalgae to improve their growth performance obtained with the initial concentration of macronutrients. This demonstrates their potential in the treatment of wastewater with a high load of major pollutants with the production of commercially valuable biomass. However, it should also be mentioned that the modification of the nutrient medium required an increase in the cultivation period for all strains (Table 2).
Ummalyma and colleagues [17] noted the attractiveness of green algae, namely Neochloris and Chlorella species, in the treatment of poultry slaughterhouse wastewater, with both algae producing similar biomass yields of 1.4 g L−1 and 1.3 g L−1, respectively. In another work, C. vulgaris cultured in flasks with pretreated wastewater had a biomass yield of 1.2 g L−1 [12]. Thus, our study is in line with the few scientific works available to date [11,12,17,18,29,30], noting that poultry slaughterhouse wastewater (both original and pretreated wastewater) has proven to be a nutritionally satisfying and accessible medium for the growth of various microalgae. In the course of our work, we were able to obtain promising data on both bioremediation and biomass production in comparison with similar works.

3.2. Biomass Composition and Its Biotechnological Potential

As noted above, one of the main indicators of the feasibility and attractiveness of developing wastewater treatment biotechnologies by using microalgae is the value of the resulting biomass as a raw material for the production of aquaculture feed, biofertilizers, and plant growth stimulants [17]. It is worth noting that the application of microalgae contributes to the development of an innovative concept of carbon neutrality in wastewater treatment processes [31]. In this work, a wide range of valuable metabolites of all tested algae was studied. Thus, at the end of each treatment, the pigment profile, protein, carbohydrate, and lipid levels in algal cells were assessed.
Currently, there are about 600 known varieties of carotenoids, among which astaxanthin, ß-carotene, fucoxanthin, lutein, canthaxanthin, and zeaxanthin are the major carotenoids of market interest [32]. Meanwhile, the carotenoid market size has grown strongly in recent years; in particular, the astaxanthin market size is expected to grow to 3.4 billion USD by 2027 [33]. Figure 4 and Table 2 demonstrate the pigment content in algal cells. Thus, microalgae significantly increased the pigment concentrations in PSW_mod experiments, with Chlorella being the microalgae with the highest content of both total chlorophylls and total carotenoids (on average, up to 63 and 12.5 mg L−1 in C. vulgaris, respectively). It should be mentioned that the final content of pigments accumulated by algal cells during growth in wastewater was comparable with the values obtained during growth in a standard synthetic nutrient medium [21] and in effluent from biogas reactors [22]. Thus, chlorophylls and carotenoids extracted from microalgal cells after wastewater treatment can be used as natural dyes or other valuable products, which emphasizes the cost-effectiveness of microalgal remediation.
Considering that animal-based protein production is strictly dependent on plant-based protein supply, the search for alternative and sustainable protein sources is among the urgent ones. The active study of microalgae as protein producers and the growing global microalgae market have opened the door to this issue. Thus, for example, in Canada, the microalga Auxenochlorella protothecoides (known as Chlorella protothecoides) strain S106, with proven safety and a high protein content (>60%), was approved as an alternative protein source [34]. Although currently only a limited number of microalgae have GRAS (generally recognized as safe) status, for example, A. protothecoides, Chlamydomonas reinhardtii, and Haematococcus lacustris (formerly known as Haematococcus pluvialis) within green algae, the list of microalgae with high levels of valuable value-added macromolecules such as food protein and bioactive peptides is constantly growing [35]. This opens up prospects for microalgae to take a worthy place in the production of safe novel food and feed products [30]. As for the protein content in algal cells (Figure 5), as in the case of pigments, an increase in N in the growth medium allowed all microalgae to actively accumulate this valuable N-containing product. Microalgae C. sorokiniana and Neochloris sp. had the highest protein content when grown in original wastewater (up to 22% of the final dry weight) and in modified medium (on average, 26% and 33% of the final dry weight, respectively). The protein content in the mentioned algal species grown in 10% effluent from biogas reactors was at a similar level [22]. In addition, C. sorokiniana cells grown in the synthetic media under distinct strategies showed similar protein values [21]. Viegas and colleagues [11] also compared the biochemical composition of Chlorella and Tetradesmus cells grown in PSW with those grown in synthetic nutrient media. The results of this work suggest that the growth of algae in raw poultry slaughterhouse wastewater resulted in more protein (two or more times), while modified wastewater (the same wastewater pretreated with ash) reduced this indicator.
Today, many microalgal polysaccharides are being actively tested for inclusion in functional beverages and food products [36], while a special place in the development of wastewater treatment using microalgae is given to the production of carbohydrates as chemical precursors of natural origin for various industries to increase the economic attractiveness of biotechnology [37]. Microalgae, which are capable of accumulating starch as the main form of carbohydrates, have been considered as a primary precursor for the production of platform chemicals [38,39]. It has also been observed that they can efficiently accumulate starch during carbon redistribution in cells grown under nutrient-limited conditions. Moreover, the conversion of carbohydrate-rich microalgal biomass is more efficient than that of lignocellulosic materials [40]. Thus, manipulating the supply of essential macronutrients has been considered an effective strategy to improve starch accumulation in algal cells, such as in species within the genera Chlorella and Chlamydomonas, grown under photoautotrophic conditions, in which the starch content reached more than 40% of dry biomass [41,42,43]. In a narrow series of studies devoted to assessing the potential of using real wastewater for starch production, the study performed by Noguchi et al. [44] is noted, in which the authors showed that the relatively low nitrogen concentration in the nutrient medium, as well as the microbial load of the wastewater, are important for the high carbohydrate content in the cells of the Chlorella microalgae. In our experiments, individual algae were also able to efficiently accumulate biomass with a high starch content. Thus, the accumulation of starch in the studied algal species was individual (Figure 5); a high content of this reserve was noted in C. sorokiniana cells grown in original wastewater (35.6 ± 2.5% of dry weight) and T. obliquus cells during growth in original and modified media (up to 34% of dry weight). Some algae (C. vulgaris, T. obliquus, Desmodesmus sp.) did not respond to the modification by increasing this reserve component of the cell, while others (C. sorokiniana and Neochloris sp.), on the contrary, decreased this reserve component, which may be associated with an increase in the supply of N, P, and S.
Interest in lipids is explained by the demand for renewable and environmentally friendly fuel sources, and the oil yield from microalgae is substantially higher than that from oil crops. It is worth noting that microalgal biomass with high lipid, carbohydrate, and protein contents and residual biomass after the extraction of high-value metabolites can be converted into biofuels [45,46]. In our experiments, by the end of the experimental period, all cultures utilized the available ammonium, which allowed the cultures to increase the proportion of protein in their biomass. While in terms of the dynamics of N loss and pigment levels, the tested algae were not in a state of N starvation, which is reflected in the average level of lipids in the cells. At the same time, Chlorella cultures responded to the modification of the growth medium with a slight increase in this metabolite, while all the others decreased its level. Desmodesmus sp. was the microalga with the highest lipid content: 29.0 ± 2.8% in PSW and 27.0 ± 2.1% in PSW_mod (Figure 5). The lowest lipid values under both tested conditions were observed in Neochloris sp. cells (17.5 ± 2.1% in PSW and 11.0 ± 1.4% in PSW_mod), and the main components in the cells of this alga were proteins. In the work of Ummalyma et al. [17], Neochloris sp. also actively accumulated proteins and lipids in PSW, with a lower proportion of carbohydrates. It is worth noting that the content of proteins, lipids, and carbohydrates in the final biomass could be influenced by the content of metabolites associated with bacterial cells (in our treatments).
In conclusion, although nutritional stress results in changes in cellular metabolic processes and the formation of energy storage products such as starch and lipids in cells [47] and also affects the content of other components of cells (for example, various carbohydrates, polyhydroxyalkanoates, pigments, and vitamins), this nutritional stress can induce oxidative stress, which causes a decrease in photosynthetic activity and, as a result, a decrease in the concentration of storage products [38]. Therefore, the compromise between the growth of microalgae, their bioremediation efficiency, and metabolite production should be carefully considered when optimizing the strategy for incorporating algae into treatment systems.

3.3. Microalgal Impacts on Composition of PSW Microbial Communities

Considering that the growth of algae is affected not only by abiotic factors but also by microbial factors, in particular by microbes coexisting with algae, i.e., the phycosphere [48,49,50], and also to investigate the influence of algae on the bacterial load of wastewater, an analysis of the bacterial composition of original PSW, as well as the bacterial community structure of water after treatment with algae, was performed. An analysis of the total microbial count (TMC) and sanitary-indicative group of microorganisms, total coliform bacteria (TCB), was carried out (Figure 6). However, despite the presence of bacteria in these systems, by the end of cultivation, algae constituted a major share in the formed microbial community.
It is worth considering that microalgae often interact with their partners, bacteria, in wastewater systems. In our case, it was noted that the introduced algal cultures did not contribute to the effective removal of coliform bacteria but at the same time did not allow them to increase their share. Thus, studies in this area note that sanitary-indicative bacteria remain in water treated with algae, which proves the difficulty of reducing the number of pathogenic bacteria and the need to develop combined purification methods [51]. In addition, the main representatives of culturable bacteria in the studied wastewater were identified (Table 3).
Furthermore, a total of 132,135 high-quality 16S rRNA gene sequences were generated with an average of 22,022 reads per sample (from 16,571 to 24,836) by using an Illumina sequencing platform. Members of the phyla Campylobacterota_A (21.6%), Bacteroidota (17.8%), Bacillota_A_368345 (13.8%), Pseudomonadota (12.5%), and Bacillota_I (12.0%) were dominant within the bacterial communities associated with original PSW. In contrast, bacterial communities formed during the growth of microalgae were dominated by members of the phyla Pseudomonadota (41.2–53.5%) and Bacteroidota (20.5–45.4%). The class-level and genus-level classifications of bacterial communities are presented in Figure 7 and Figure 8, respectively. Campylobacteria, Bacteroidia, Clostridia, Gammaproteobacteria, and Bacilli_A were the major classes observed in original PSW. In contrast, bacterial communities formed in the presence of all microalgae were mainly dominated by representatives of the classes Bacteroidia, Alphaproteobacteria, and Gammaproteobacteria (Figure 7).
The bacterial communities demonstrated the relative individuality in composition after cultivation of the tested microalgae. Bacterial representatives, namely unknown Arcobacteraceae (24.1%) and Sulfurospirillum_A (3.0%) of the class Campylobacteria, Prevotella (3.3%), Macellibacteroides (2.7%), and Bacteroides_G (2.8%) of the class Bacteroidia, Corynebacterium (3.9%) of the class Actinomycetes, UBA12465 (3.7%) of the class ABY1, Faecousia (2.6%), Clostridium (1.6%), and Clostridium_T (1.0%) of the class Clostridia, Accumulibacter (2.5%) and unclassified Enterobacterales (1.9%) of the class Gammaproteobacteria, and Streptococcus (2.0%) of the class Bacilli, were detected only in original PSW and eliminated during cultivation of all microalgal cultures (Figure 8).
Such representatives as Arcobacteraceae and Sulfurospirillaceae play an important role in the decomposition of organic matter in various ecological niches, including wastewater [52,53]. The reduction in the relative abundance of Arcobacteraceae, a family widely distributed in untreated wastewater and responsible for human and animal diseases [53,54], as well as distinct pathogens of the genus Clostridium, has been associated with the growth of algae and is promising for sanitary microbiology [55]. Representatives of the methanogenic archaea of the classes Methanobacteria and Methanomicrobia were also detected in original PSW. Strict anaerobes (methanogens, clostridia, and sulfate reducers), microaerophiles, and waterborne pathogens could be displaced by algae in various ways, by molecular oxygen production, by the release of toxins and bactericides, or through photooxidative processes [55,56]. It should be noted that in the studied wastewater communities, such important and sensitive members of bioremediation communities as nitrifying bacteria, which convert ammonium to nitrate, were not found.
As visible in Figure 7 and Figure 8, the growth of all algae in PSW affected the microbial composition in each system. All algae reduced the relative abundance of mentioned Campylobacteria, Bacilli, and Clostridia and members of other minor classes, while increasing the relative abundance of Alphaproteobacteria, Gammaproteobacteria, and Bacteroidia members. Individual bacterial representatives occupied a significant share by the end of algae cultivation, in particular, members of the genus Sediminibacterium. Representatives of this genus, often isolated from sediment [57] and activated sludge [58] and considered as aerobic microalgae-associated bacteria, were detected in all our systems with algae (with lower relative abundance in the system with C. vulgaris, in which these microbes were displaced by other bacterial representatives). Sediminibacterium sp. strain SCP4 exerted the strongest growth-promoting effect on C. reinhardtii [59], and representatives of this genus were among the dominant indigenous bacteria in secondary effluent of municipal and swine wastewater, affecting C. reinhardtii, C. vulgaris, and Euglena gracilis [60]. Of note is a study performed by Sethuraman et al. [61], in which a representative of the genus Sediminibacterium was isolated from laboratory cultures of two stream benthic cyanobacterial strains grown in BG11 medium. The authors noted the presence of genes of bacterial colonizers that may be involved in their mutualistic/commensal relationships with hosts.
It should be noted that such members of the genera as Brevundimonas, Stenotrophomonas, Prosthecobacter, Peredibacter, Flavobacterium, Devosia, and Bosea also developed during the growth of microalgae in wastewater, and many of them have a stimulating effect on the growth of algae. Thus, bacteria of the genus Brevundimonas [62,63] and nitrogen-fixing bacteria of the genus Devosia, which promote plant growth [64], are beneficial for microalgae and are able to modulate the maturation of microalgal-bacterial biofilms, which has a positive effect on the efficiency of bioremediation communities [65]. Another genus of microalgae growth-promoting bacteria, Flavobacterium [66], is also capable of forming biofilms and can be used to harvest microalgae [67]. Stenotrophomonas species are considered candidates for bioremediation due to their ability to metabolize a wide range of organic molecules, including phenolic and aromatic compounds [68], while algae can build both mutualistic relationships with them [49] and inhibit their development [48].
Among the dominant pure bacterial cultures isolated from the poultry slaughterhouse primary wastewater were members of the genera Aeromonas, Shewanella, Citrobacter, Pseudomonas, Stenotrophomonas, and Escherichia. It is worth noting that the analysis of the bacterial community showed a decrease in the relative abundance of mobile bacteria of the genus Aeromonas as causative agents of diarrhea and wound infections, dangerous pathogens of fish [69], after culturing the studied algae in wastewater (however, these bacteria were in minimal proportions). These pathogenic microorganisms are found in chicken feces, carcasses, slaughter water at the processing plant [70], and treated wastewater effluent and are characterized by resistance to antimicrobial drugs [71]. Therefore, their reduction by the introduction of microalgae is considered a sustainable biotechnology for improving wastewater safety.

4. Conclusions

Five green algae species were cultured in PSW in full-factorial photobioreactor experiments. To adjust the composition of the algal growth medium, ammonium, phosphate, and sulfate ions were added to PSW. Chlorella species demonstrated the high biomass yield when grown in modified PSW and had valuable qualitative and quantitative biomass indices. T. obliquus grown in PSW accumulated starch (up to 34% of dry weight), while Desmodesmus sp. accumulated lipids more efficiently than other cultures (up to 29% of dry weight). When cultivating the tested algae, their positive effect on the quality of the wastewater was revealed: ammonium, phosphate, and sulfate were completely utilized by C. sorokiniana, C. vulgaris, T. obliquus, and Desmodesmus sp., and the microbiological indicators of the wastewater were improved. At the same time, microbiological analysis of PSW allowed us to consider it as a source of effective bacteria capable of stimulating the growth of microalgae (such as Sediminibacterium, Brevundimonas, Stenotrophomonas, Flavobacterium, and Devosia). Considering that metabolites and signal molecules exchanged between bacteria and algae within the phycosphere determine the nature of their relationships, identifying the specifics of their interaction and identifying the effector molecules that trigger their affiliation in anthropogenic wastewater treatment systems will open up new directions for both fundamental and applied research. The obtained results indicate the potential for including green algae in wastewater treatment systems at poultry farms.

Author Contributions

Conceptualization, E.E.Z. and A.M.Z.; methodology, E.E.Z. and A.M.Z.; investigation, E.E.Z., K.A.Y. and A.M.Z.; writing—original draft preparation, E.E.Z.; writing—review and editing, K.A.Y. and A.M.Z.; visualization, E.E.Z.; supervision, A.M.Z.; funding acquisition, E.E.Z. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Russian Science Foundation and the Academy of Sciences of the Republic of Tatarstan under project No. 25-24-20037 (https://rscf.ru/en/project/25-24-20037/, accessed on 4 September 2025).

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Conflicts of Interest

The authors declare no conflicts of interest.

Abbreviations

The following abbreviations are used in this manuscript:
BBMBold’s basal medium
CFUcolony-forming units
DWdry weight
OD750nmoptical density at 750 nm
PSWpoultry slaughterhouse wastewater
PSW_modmodified poultry slaughterhouse wastewater
TBCtotal bacterial count
TCBtotal coliform bacteria
VSvolatile solids

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Figure 1. Biomass yield obtained during growth of cultures (C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3) in original and modified duck slaughterhouse wastewater. Means that do not share a letter are significantly different (Tukey method and 95% confidence).
Figure 1. Biomass yield obtained during growth of cultures (C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3) in original and modified duck slaughterhouse wastewater. Means that do not share a letter are significantly different (Tukey method and 95% confidence).
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Figure 2. NH4+–N removal during growth of C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3 in wastewater.
Figure 2. NH4+–N removal during growth of C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3 in wastewater.
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Figure 3. Change in pH during growth of C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3 in wastewater.
Figure 3. Change in pH during growth of C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3 in wastewater.
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Figure 4. Final concentration of total chlorophylls and total carotenoids obtained during growth of cultures (C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3) in wastewater. Means that do not share a letter are significantly different (Tukey method and 95% confidence; green letters refer to chlorophylls concentration; orange letters—carotenoids concentration).
Figure 4. Final concentration of total chlorophylls and total carotenoids obtained during growth of cultures (C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3) in wastewater. Means that do not share a letter are significantly different (Tukey method and 95% confidence; green letters refer to chlorophylls concentration; orange letters—carotenoids concentration).
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Figure 5. Protein, starch, and lipid content of biomass obtained during growth of cultures (C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3) in wastewater. Means that do not share a letter are significantly different (Tukey method and 95% confidence; blue letters refer to protein content; grey letters—starch content; orange letters—lipid content).
Figure 5. Protein, starch, and lipid content of biomass obtained during growth of cultures (C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3) in wastewater. Means that do not share a letter are significantly different (Tukey method and 95% confidence; blue letters refer to protein content; grey letters—starch content; orange letters—lipid content).
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Figure 6. Bacterial loading in PSW before and after cultivation of C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, Neochloris sp. EE-K3. (A)—total microbial count; (B)—total coliform bacteria; log CFU—colony-forming units expressed using logarithmic notation.
Figure 6. Bacterial loading in PSW before and after cultivation of C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, Neochloris sp. EE-K3. (A)—total microbial count; (B)—total coliform bacteria; log CFU—colony-forming units expressed using logarithmic notation.
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Figure 7. Prokaryotic community composition of original wastewater and wastewater after cultivation of algae (C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, Neochloris sp. EE-K3) according to sequencing of 16S rRNA gene amplicons (class level).
Figure 7. Prokaryotic community composition of original wastewater and wastewater after cultivation of algae (C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, Neochloris sp. EE-K3) according to sequencing of 16S rRNA gene amplicons (class level).
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Figure 8. Heatmap demonstrating the relative abundances of microbial taxa in original wastewater and wastewater after cultivation of microalgae (C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3) according to sequencing of 16S rRNA gene amplicons (genus level). Only taxa comprising at least 1.5% relative abundance in at least one sample are presented.
Figure 8. Heatmap demonstrating the relative abundances of microbial taxa in original wastewater and wastewater after cultivation of microalgae (C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3) according to sequencing of 16S rRNA gene amplicons (genus level). Only taxa comprising at least 1.5% relative abundance in at least one sample are presented.
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Table 1. Characteristics of poultry slaughterhouse wastewater used for cultivation of green algae: C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3.
Table 1. Characteristics of poultry slaughterhouse wastewater used for cultivation of green algae: C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3.
TreatmentpHNH4+–N, mg L−1PO43−–P, mg L−1SO42−–S, mg L−1
AM-02_PSW7.32 ± 0.0267 ± 3.8 11 ± 0.53 ± 0.4
AM-02_PSW_mod7.43 ± 0.01144 ± 1.235 ± 0.410 ± 0.2
SB-M4_PSW7.09 ± 0.0265 ± 1.4 9 ± 0.83 ± 0.7
SB-M4_PSW_mod7.21 ± 0.02143 ± 1.734 ± 0.610 ± 0.3
EZ-B11_PSW7.30 ± 0.0360 ± 1.49 ± 0.64 ± 0.6
EZ-B11_PSW_mod7.08 ± 0.02144 ± 1.635 ± 0.711 ± 0.3
EE-M8_PSW7.15 ± 0.0262 ± 1.810 ± 0.42 ± 0.5
EE-M8_PSW_mod7.11 ± 0.01145 ± 1.736 ± 0.210 ± 0.5
EE-K3_PSW7.10 ± 0.0165 ± 1.711 ± 0.73 ± 0.2
EE-K3_PSW_mod6.93 ± 0.02142 ± 4.335 ± 0.411 ± 0.4
PSW—poultry (duck) slaughterhouse wastewater; PSW_mod—modified poultry slaughterhouse wastewater (with addition of extra N, P, and S).
Table 2. Characteristics of obtained biomass and the efficiency of P and S removal during the cultivation of C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3 in wastewater.
Table 2. Characteristics of obtained biomass and the efficiency of P and S removal during the cultivation of C. sorokiniana AM-02, C. vulgaris SB-M4, T. obliquus EZ-B11, Desmodesmus sp. EE-M8, and Neochloris sp. EE-K3 in wastewater.
TreatmentVolatile
Solids,
g L−1		Biomass
Productivity,
g L−1 day−1		Final
Pigments,
% of DW		PO43−–P
Removal,
%		SO42−–S
Removal,
%		Period of
Cultivation, Day
AM-02_PSW2.82 ± 0.16 b0.49 ± 0.03 cd0.93 ± 0.05 b1001007
AM-02_PSW_mod4.13 ± 0.19 a0.62 ± 0.03 ab1.69 ± 0.08 a1001008
SB-M4_PSW2.96 ± 0.15 b0.52 ± 0.02 abc0.67 ± 0.03 c1001007
SB-M4_PSW_mod4.25 ± 0.11 a0.63 ± 0.03 a1.71 ± 0.07 a1001008
EZ-B11_PSW2.88 ± 0.14 b0.51 ± 0.03 bcd0.56 ± 0.03 c1001007
EZ-B11_PSW_mod3.90 ± 0.18 a0.50 ± 0.02 cd1.56 ± 0.07 a1001008
EE-M8_PSW2.94 ± 0.14 b0.52 ± 0.03 abc0.64 ± 0.04 c1001007
EE-M8_PSW_mod3.93 ± 0.17 a0.51 ± 0.03 bcd1.47 ± 0.08 a1001008
EE-K3_PSW2.21 ± 0.11 c0.41 ± 0.02 de0.71 ± 0.03 bc1001007
EE-K3_PSW_mod2.43 ± 0.14 bc0.34 ± 0.02 e1.54 ± 0.10 a81 ± 388 ± 48
Means that do not share a letter are significantly different (Tukey method and 95% confidence).
Table 3. Sequencing results of 16S rRNA genes of representative dominant bacterial isolates from original duck slaughterhouse wastewater.
Table 3. Sequencing results of 16S rRNA genes of representative dominant bacterial isolates from original duck slaughterhouse wastewater.
Isolate (bp)Highest BLAST+ 2.17.0 Hit (Acc. No.)/Percent IdentityTaxonomic Affiliation
PSW_1 (737)Aeromonas salmonicida strain CECT 894 (NR_043324.1)/98.7%Aeromonas sp.
PSW_2 (640)Aeromonas salmonicida strain CECT 894 (NR_043324.1)/97.3%Aeromonas sp.
PSW_3 (830)Aeromonas media strain RM (NR_036911.2)/99.8%Aeromonas sp.
PSW_4 (823)Shewanella putrefaciens strain Hammer 95 (NR_044863.1)/99.8%Shewanella sp.
PSW_5 (844)Citrobacter gillenii strain CDC 4693-86 (NR_041697.1)/100%Citrobacter sp.
PSW_6 (849)Citrobacter gillenii strain CDC 4693-86 (NR_041697.1)/99.9%Citrobacter sp.
PSW_7 (827)Pseudomonas putida strain NBRC 14164 (NR_113651.1)/98.4%Pseudomonas sp.
PSW_8 (895)Pseudomonas putida B33 (KT767698)/99.7%Pseudomonas sp.
PSW_9 (812)Pseudomonas sp. CmLB7 (HM352331)/99.9%Pseudomonas sp.
PSW_10 (835)Stenotrophomonas lactitubi strain M15 (NR_179509.1)/98.8%Stenotrophomonas sp.
PSW_11 (807)Stenotrophomonas tumulicola cqsG1 (MN826536)/99.5%Stenotrophomonas sp.
PSW_12 (885)Stenotrophomonas sp. V10R15 (MT165571)/100%Stenotrophomonas sp.
PSW_13 (805)Escherichia coli MAK15 (OP060224)/99.9%Escherichia coli
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Ziganshina, E.E.; Yureva, K.A.; Ziganshin, A.M. Poultry Slaughterhouse Wastewater Treatment by Green Algae: An Eco-Friendly Restorative Process. Environments 2025, 12, 331. https://doi.org/10.3390/environments12090331

AMA Style

Ziganshina EE, Yureva KA, Ziganshin AM. Poultry Slaughterhouse Wastewater Treatment by Green Algae: An Eco-Friendly Restorative Process. Environments. 2025; 12(9):331. https://doi.org/10.3390/environments12090331

Chicago/Turabian Style

Ziganshina, Elvira E., Ksenia A. Yureva, and Ayrat M. Ziganshin. 2025. "Poultry Slaughterhouse Wastewater Treatment by Green Algae: An Eco-Friendly Restorative Process" Environments 12, no. 9: 331. https://doi.org/10.3390/environments12090331

APA Style

Ziganshina, E. E., Yureva, K. A., & Ziganshin, A. M. (2025). Poultry Slaughterhouse Wastewater Treatment by Green Algae: An Eco-Friendly Restorative Process. Environments, 12(9), 331. https://doi.org/10.3390/environments12090331

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