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Review

Prospects of Algal Strains for Acidic Wastewater Treatment

by
Paulina Slick
1,
Neha Arora
2,3,*,
Enlin Lo
4,
Diego Santiago-Alarcon
1 and
George P. Philippidis
1,3,*
1
Department of Integrative Biology, University of South Florida, Tampa, FL 33620, USA
2
Department of Biology, Skidmore College, Saratoga Springs, NY 12866, USA
3
Patel College of Global Sustainability, University of South Florida, Tampa, FL 33620, USA
4
Department of Molecular Biosciences, University of South Florida, Tampa, FL 33620, USA
*
Authors to whom correspondence should be addressed.
Appl. Sci. 2026, 16(1), 216; https://doi.org/10.3390/app16010216
Submission received: 11 November 2025 / Revised: 13 December 2025 / Accepted: 20 December 2025 / Published: 24 December 2025
(This article belongs to the Special Issue New Approaches to Water Treatment: Challenges and Trends, 2nd Edition)
Browse Figure
Versions Notes

Abstract

Rapid industrialization has generated large volumes of acidic wastewater that, without adequate treatment, pose serious environmental and public health risks. Traditional remediation processes, such as chemical neutralization, ion-exchange, and membrane filtration, are effective but costly, energy-intensive, and generate toxic secondary waste. In contrast, acidophilic microalgae offer a sustainable, cost-effective, and eco-friendly alternative. Algae rely on their cellular structure and metabolism to adsorb, absorb, bioaccumulate, and transform toxic metals while simultaneously neutralizing wastewater with minimal secondary waste production. Although acidophilic algae tolerate highly toxic and low pH conditions, their growth rate and biomass productivity, key drivers of algae-based bioremediation, are often compromised under such conditions. Thus, identifying robust species and evolving strains to thrive in these wastewaters without compromising productivity will facilitate adoption of algae-based bioremediation on a large scale. Integrating algal wastewater remediation with biofuel and biofertilizer production can contribute to the circular economy. In this review, we synthesize mechanisms employed by acidophilic algal strains when exposed to acidic and metal-enriched environments to remediate wastewater. We highlight recent studies applying these strains to acidic wastewater remediation and biogas upgrading and discuss current biotechnological tools aimed at enhancing strain performance for future use in commercial systems.

1. Introduction

The production of anthropogenic acidic wastewater by mining operations and other industrial activities increases the risk of exposure to, and leaching of, toxic heavy metals and other harmful chemicals into the environment, thereby posing serious health hazards to humans and other organisms [1,2]. Prolonged or repeated exposure to acidic wastewater and its heavy metals, toxic organic pollutants, and pathogens degrades soil quality and facilitates the transport of pathogens through the soil, ultimately threatening the quality of water used for drinking and irrigation [3,4].
The major sources of acidic wastewater include mining operations, waste management facilities, chemical and fertilizer industries, and metal manufacturing. These activities generate effluents such as acid mine drainage (AMD), landfill leachates, and non-ferrous metal smelting operations (Table 1). Acidic wastewater typically contains a mixture of inorganic materials (ferric acid and heavy metals), organic materials, nutrients such as nitrates and phosphates (P), and pathogens [5]. Each wastewater type exhibits a characteristic pH range and metal profile. For example, AMD has a very low pH of 2.0–4.5 and contains several dissolved metals, including Fe2+/Fe3+, Mg2+, Cu2+, Mn2+, and Zn2+ as well as other trace elements [6].
The treatment of acidic effluents is challenging because their low pH and complex mixture of inorganic and organic contaminants require labor-intensive and costly management strategies [14]. Conventional remediation approaches include pH neutralization, extraction, adsorption, distillation, metal precipitation, coagulation, and flocculation processes [5,15,16]. One of the first steps for treating acidic wastewater is neutralization with alkaline chemicals, such as calcium oxide, sodium bicarbonate, sodium carbonate, silicon dioxide, and magnesium oxide [17]. However, this process generates substantial quantities of secondary sludge that require additional treatment and disposal [18]. Moreover, traditional methods typically consist of multi-step processes that consume large volumes of chemicals, produce toxic sludge, and require high energy inputs, particularly when lime-based neutralization is involved [18]. Thus, although these techniques can be effective, current acidic wastewater treatment poses environmental hazards, limiting their sustainable future while requiring increased energy input and costly chemicals [5,15,16], which also elevate greenhouse gas emissions, further impacting the environment [19].
In contrast, biological methods—particularly those using microorganisms, such as bacteria, fungi, and microalgae—offer promising alternatives due to their lower energy requirements and potential for resource recovery [5]. These organisms remediate wastewater using their metabolic pathways and typically do so without generating the harmful sludge associated with conventional purification methods [20]. Among them, microalgae are especially attractive because they can adsorb metals onto their cell walls, followed by bioaccumulation, and then transformation of metals into less toxic forms to mitigate wastewater toxicity [21]. Algae also assimilate waste-derived nitrogen, phosphorus, and various organic pollutants. As a result, algae have been gaining momentum for their bioremediation capabilities [22]. Algal strains can simultaneously treat wastewater and generate valuable biomass that could be valorized for several biotechnological applications, such as bioenergy, biofertilizers, biochar, and additive materials, further increasing their attractiveness as an alternative to traditional wastewater treatment [23]. Additionally, they represent a more sustainable treatment solution as they generate less secondary waste, contribute to cleaner water effluent, and help reduce carbon emissions [24].
Neutrophilic algae, which thrive in environments near pH 7, have recently been explored for wastewater treatment applications [25,26,27]. Algal strains such as Chlamydomonas noctigama, Chlorococcum texanum, Scenedesmus longus, Haematococcus lacustris, and Chlorella fusca var. vacuolata have shown an ability to adapt to domestic to industrial wastewaters. However, their productivity was low, falling short of levels required for economically viable commercial operations [28]. This is indicative of the fact that neutrophilic algae face limitations, including growth inhibition at low pH, higher susceptibility to contamination by unwanted organisms, and resource availability for maintaining optimal growth parameters, such as light, temperature, neutral pH, and carbon dioxide (CO2) enrichment [29]. These neutrophilic strains are at a disadvantage when compared to extremophilic algae, specifically acidophilic and acid-tolerant algae, which thrive in acidic conditions at a range of pH 0–6. Low pH-resilient algae have a more robust metabolic composition, allowing the cells to maintain optimal growth performance regardless of fluctuating environmental conditions. This resilience increases their productivity and remediation efficiency while reducing cultivation and treatment costs [14].
Importantly, certain acidic wastewaters, particularly landfill leachates, contain elevated levels of carbon dioxide derived from landfill gas emissions [30]. This excess CO2 can serve as an inexpensive carbon source for algal growth, reducing or even eliminating the need for supplemental CO2, which represents a significant cost (USD 1.47–7.33 per kg) in large-scale cultivation [14,22]. Acidophilic algae are inherently tolerant to high CO2 concentrations and can utilize carbon and nitrogen (N) from flue gases generated at wastewater treatment facilities [22,31]. To maintain intracellular pH homeostasis under high CO2, these algae rely on several cellular mechanisms, including increased ATP production, enhanced proton export from the cell to prevent intracellular acidification through expulsion of hydrogen ions, modifications to membrane fatty acid composition to increase membrane stability, and downregulation of the carbon-concentrating mechanism [32]. Moreover, certain extremophilic strains, like Chloroccum littorale, have been shown to maintain an increased growth rate in the presence of high CO2 [32]. Other acidophilic algal strains, such as Galdieria sulphuraria, have both efficient wastewater remediation capacity and the ability to suppress bacterial competitors, reducing up to 98% in wastewater systems [24]. Additional genera such as Chlorella, Scenedesmus, and Oscillatoria can tolerate acidic mine effluents at pH 2.5 to 5 [14,25]. Furthermore, acid-tolerant strains such as Chlamydomonas sp., Desmodesmus sp., and Heterochlorella sp. grow optimally at pH 4–6 but can withstand pH values as low as 2–3, making them well-suited for treating acidic wastewaters under fluctuating environmental conditions [21,33]. This is demonstrated in outdoor reactor systems, where pH fluctuates with flow rate, remediation stage, and rain/evaporation.
In this review, we assess the potential of acidophilic and acid-tolerant algae strains for the treatment of acidic wastewaters. We discuss the mechanisms that enable these organisms to adapt to low-pH environments and remediate metal-rich effluents through a suite of cellular responses. Using this information, we provide recommendations for improving the performance of promising acidophilic and acid-tolerant strains cultivated in acidic wastewaters through random mutagenesis, adaptive laboratory evolution (ALE), and genetic engineering. We also highlight the emerging use of quantum computing models as a tool for predicting advantageous mutations under specific stressors, thereby reducing reliance on trial-and-error approaches in strain development. To the best of our knowledge, this is the first review to specifically integrate mechanistic understanding, strain improvement strategies, and technological innovations focused on acidophilic and acid-tolerant algae for acidic wastewater treatment.

2. Algal Mechanisms for Acidic Wastewater Treatment

Acidophilic and acid-tolerant algae have developed several genetic adaptations that allow for their survival in low pH environments [33]. Acidophilic and acid-tolerant strains in pH niches ranging from 0–9, as listed in Table 2, highlight the ability of these algae to survive in various acidic wastewaters. It is important to note that even at low pH, these algae need to maintain a nearly neutral cytosolic pH for critical ATP synthase performance [34]. In acidic conditions where protons are abundant, these algae employ multiple metabolic pathways and transport mechanisms to limit proton influx and maintain intracellular pH homeostasis [35]. Notably, acidophilic algae can neutralize excess protons through regulation of photosynthesis and cellular respiration to avoid overproduction of protons within their cytosol [32]. Furthermore, proteins such as V-type H+-ATPases, P-type H+-ATPases, and V-PPases use either ATP hydrolysis or pyrophosphatase cleavage as an energy source to limit the presence of protons intracellularly [35]. Protons are either translocated by those proteins outside of the cell or are compartmentalized in the algal cell vacuoles [35]. Additionally, acidophilic algae tend to have a positive membrane potential and surface charge that physically limit the influx of protons [36]. Beyond tolerating low pH, these algae have also adapted to utilize wastewater-derived nutrients and pollutants, including nitrites, ammonium, and heavy metals, through metabolic pathways that support both growth and remediation [37]. This differentiates acidophilic strains from neutrophilic strains, as they can effectively utilize high concentrations of ammonium and nitrites as their nitrogen source from within the wastewater [38].

2.1. Passive Biosorption

Algal strains can detoxify heavy metals found in acidic wastewater, such as AMD, by adsorbing the metal contaminants on their surface and then safely sequestering them into their vacuoles [39,40]. The surface of algal cells consists of proteins, polysaccharides, and lipids containing chemical locations that expose functional groups (carboxyl, sulfate, amino, phosphate, hydroxyl, and amines) and allow for binding of cationic metal ions, such as iron (Fe), sodium (Na), and copper (Cu) [41]. Through biosorption, the metal ions adhere onto the cell surface via electrostatic attraction, ion exchange, and complex formation [38]. Biosorption is typically a fast and passive process, occurring upon exposure to heavy metals and does not rely on metabolic energy to function [38,42]. It is important to note that the efficiency of this process is sensitive to environmental conditions. Specifically at low pH, the chemical sites located on the cellular surface of neutrophilic algae become protonated, as hydrogen ions occupy those sites, reducing availability for metal binding [42]. In contrast, acidophilic algae maintain metal-binding capacity at low pH because their cell wall architecture and polymer arrangements reduce proton competition for functional groups. Although in acid-tolerant algae the cell wall functional groups remain partially deprotonated, their high biomass production under acidic conditions enhances the total metal-binding capacity. These algae also modify their cell wall composition in response to acidic stress, further improving metal-binding efficiency [43]. Moreover, both acidophilic and acid-tolerant algae secrete acid-stable polysaccharide substances that create negatively charged microenvironments, enabling positively charged metal ions to bind to the algal cell surface [44]. Finally, these extracellular polysaccharides act as a protective barrier, preventing further metal entry once surface binding sites are saturated and thereby reducing cytotoxicity [45,46].

2.2. Active Bioaccumulation

After biosorption, both acidophilic and acid-tolerant algae internalize the metals through bioaccumulation, which is a slower intracellular process that involves active transport of metal ions across the cell membrane [47]. Once the metal ions are located within the cell, they may be transported to the cytoplasm or compartmentalized inside vacuoles, reducing their toxic effects on cellular constituents and functions [48]. Acid-tolerant algae often exhibit an increase in cell size, potentially due to the development of large, dynamic vacuoles, although ultrastructural studies are still required to clarify how pH influences vacuole morphology [48]. Metal ions are chelated by metallothionenins or phytochelatins, further mitigating cytotoxicity [49]. In addition, acid-tolerant algae adjust their physiology by producing amino acids such as proline, glutamate, and lysine to help maintain intracellular homeostasis, while also increasing antioxidant levels, including superoxide dismutase and ascorbate peroxidase, to reduce oxidative stress [40,50].
Naturally resistant acidophilic strains, such as G. sulphuraria and Chlamydomonas sp., have been studied for their wastewater and heavy metal remediation capabilities. G. sulphuraria has been shown to remediate cadmium (Cd II), lead (Pb II), nickel (Ni II), and zinc (Zn II) with the highest removal efficiencies being 45.9%, 25.1%, 6.6%, and 28.6%, respectively, when grown at pH 2.5, while Chlamydomonas sp. reached a removal efficiency of 95.6% when exposed to Cd II in an industrial effluent at pH 4 [21,51]. Another acid-tolerant strain, Grasiella sp. MA1, exhibits strong resistance to copper (Cu II) and manganese (Mn II), removing over 53% of Cu II and more than 35% of Mn II when grown at 2 mg/L of each metal [52]. Together, these findings highlight the strong potential of acidophilic algae to remediate acidic wastewaters and reduce metal loads in contaminated environments.
In addition, several studies have generated evolved strains that can survive in acidic conditions. Non-acidophilic strains can adapt their phenotypic responses to environments with elevated heavy metal concentrations and low pH, ultimately becoming acid-tolerant strains. Examples of strains adapted to withstand heavy metals include Desmodesmus sp. MAS1 and Heterochlorella sp. MAS3, both of which were successfully cultured in medium at pH 3.5 and remediated 2–20 mg/L of Cd [33]. The authors reported these two adapted strains not only thrived at low pH conditions but also increased accumulation of heavy metals, including Cu, Fe, Mn, and Zn [33]. Exposure to heavy metals in AMD decreased cellular chlorophyll content and increased lipid accumulation in these strains, reflecting a metabolic response to oxidative stress. Non-acidophilic algal strains can also adapt via alterations to their biochemical composition, with production of carbohydrates, lipids, and proteins changing when exposed to different conditions [33]. In addition to these adaptations, acid-tolerant algal strains can increase resistance to metal toxicity through production of heat shock proteins [53]. Notably, acid-tolerant strains are capable of bioaccumulating a broad repertoire of metals, whereas the uptake of metals by acidophilic strains is often specialized for Fe2+/Fe3+, Cu2+, and As3+/As5+ depending on their specific environment.
Another study, which focused on genomic alterations in extremophilic red algae, reported that strains within Galdieria sp. and Cyanidium sp. were found to have the enzyme mercuric reductase (merA), which promotes the reduction of mercuric ions Hg(II) to the less toxic form of elemental Hg(0) [54]. Beyond Hg detoxification, these cells also exhibited unique arsenic (As) detoxification pathways, allowing for the excretion of monomethylated, dimethylated, and trimethylated As metabolites, thus transforming As into a less toxic form [55]. In Galdieria species, the presence of various genes, including arsenite efflux pump (arsB) and arsenate reductase (arsC), allows for efficient arsenic resistance. These genes assist the cells with oxidation of arsenite As(III) to arsenate As(V) [54]. Additionally, phosphate transporter genes and aquaglyceroporin genes were found to be overexpressed in C. eustigma, enhancing uptake and handling of both As(V) and As(III) under acidic conditions [34].
When algae are exposed to heavy metals, changes in gene expression lead to increased synthesis of proteins and transporters that carry out uptake, sequestration, and detoxification of those metals. At the cell membrane, various types of metal transport proteins facilitate the uptake of metal ions using a proton gradient. Notable transporter groups involved in this process, as shown in Figure 1, include iron transporters (FTR), copper transporters (CTR), ZRT/IRT-like proteins, P-type ATPases, and NRAMP (natural resistance-associated macrophage proteins), which facilitate the uptake and efflux of heavy metals [56]. As mentioned earlier, once the metal ion is inside the cytoplasm, it is chelated by thiol-containing molecules, such as glutathione, phytochelatins, or metallothionines, thus decreasing metal toxicity to the cell [49]. These complexes are then compartmentalized into vacuoles via ATP-binding cassette transporters (ABC transporters), where they are sequestered and detoxified [57]. This mechanism was demonstrated in a study using Chlamydomonas reinhardtii exposed to high concentrations of lead (Pb), where upregulation of these ABC transporters was observed [57]. This finding highlights the central role of ABC transporters in metal sequestration pathways. In addition to vacuolar sequestration, cells can also mitigate metal toxicity by exporting excess ions back into the environment through efflux transporters, which prevent intracellular accumulation and cytotoxicity [49]. Some expelled metals may be chelated or converted into less toxic forms, although residual toxicity may persist in the surrounding environment [49].
Table 2. The pH ranges of acidophilic and acid-tolerant algae.
Table 2. The pH ranges of acidophilic and acid-tolerant algae.
AlgaepH RangeReference
Chlamydomonas acidophila LAFIC-0042.5–8.0[58]
Chlamydomonas eustigma2.0–6.0[34]
Chlamydomonas reinhardtii3.0–9.0[59]
Coccomyxa onubensis2.5–3.0[60]
Coccomyxa sp3.0–7.0[61]
Cyanidium sp.1.4–2.5[62]
Desmodesmus sp. MAS13–10.5[63]
Euglena sp.3.0–8.0[64]
Galdieria sulphuraria0–4[65]
Heterochlorella sp. MAS33–10.5[63]
Oscillatoria sp.2.93–6.78[66]
Pseudochlorella sp. YKT13.0–5.0[67]
Scenedesmus parvus3.0–9.0[68]
Tetratostichococcus sp. P13.0–8.0[69]

3. Algal Potential for Biogas Upgrading

Anaerobic digestion of organic matter is a common microbial process in wastewater treatment [70,71]. A renewable byproduct of this process is biogas that can be recovered and used for power and heat generation [70,71]. This can serve as a promising alternative to fossil fuels once it is purified from contaminants that are present in the gas [72]. Crude biogas is primarily composed of methane (CH4), CO2, and trace amounts of water, oxygen, and harmful hydrogen sulfide; the latter is both toxic and corrosive, lowering the calorific value of the gas and damaging equipment [71,73,74,75].
To overcome these issues, conventional purification processes are employed for upgrading biogas into pure methane as a sustainable alternative to natural gas [76]. Common techniques of biogas upgrading consist of chemical adsorption, water scrubbing, cryogenic separation, and membrane separation [77]. These processes remove CO2 and other impurities from the crude biogas, yielding high-purity methane that meets market standards of greater than 90% CH4 [78]. However, these technologies rely on costly chemicals, high-pressure systems, and substantial energy inputs, which increase the overall operational cost of biogas upgrading [79]. For that reason, alternative approaches incorporating algae, bacteria, and fungi are being studied as more economical and sustainable solutions [80,81,82]. Among these options, algae stand out due to their ability to upgrade biogas while simultaneously reducing energy demand and operational cost, all while producing valuable biomass [83]. Algae can be cultured using biogas slurry as the growth medium and can sequester the CO2 within biogas while simultaneously releasing oxygen via photosynthesis [83]. This natural process represents a cost-effective and environmentally conscious method for purification of crude biogas. Algal biomass can be used within various industries for biofuel production and wastewater treatment, supporting energy recovery within a circular economy [83].
In biogas upgrading studies, biogas purification along with nutrient removal from its effluent has been studied to determine commercial potential [83]. Common performance metrics are methane concentration (as percentage), as it directly reflects the effectiveness of CO2 removal and overall gas purification; consumption of oxygen through oxidation of the organic nutrient source, referred to as chemical oxygen demand (COD); along with total nitrogen (TN) and total phosphorus (TP) present in the sample [84]. It is important to note that biogas upgrading systems typically operate at slightly acidic pH (5.5–6.5), where elevated CO2 levels can inhibit neutrophilic algal performance. Consequently, acid-tolerant algal strains, which grow optimally at pH 3–6, are well-suited for biogas upgrading because of their greater tolerance to CO2, sulfide, and metal stress.
Although no study to date has reported the use of acid-tolerant algae for biogas upgrading, research on neutrophilic algae provides valuable insights into the potential and feasibility of this approach. For instance, a study conducted using Chlorella vulgaris, Scenedesmus obliquus, Selenastrum capricornutum, Nitzschia palea, and Anabaena spiroides reported a CH4 concentration increase to 79% when crude biogas was provided to monocultures [83]. These strains were exposed to pretreated biogas containing 67.2% CH4, 29.6% CO2, 3.0% H2O, 0.21% O2, and <0.005% H2S. The highest-performing monoculture strain was S. obliquus, which removed 70.27% of COD, 69.37% of total nitrogen, and 62.55% of total phosphorus. Although these strains demonstrated the potential of algae as a biogas-upgrading alternative, they failed to reach a high enough CH4 purity for commercial applications (>90%). To improve algal performance, researchers have begun exploring modifications to light-related growth conditions [80]. Specifically, one study exposed C. vulgaris to three different light intensities (300 to 400 μmol/m2/s) under varying photoperiods [80]. The samples were cultured using pretreated biogas containing 70.7% CH4, 26.1% CO2, 3.1% H2O, 0.23% O2, and <0.005% H2S. The results showed that at 350 μmol/m2/s with a photoperiod of 14 h light and 10 h darkness, CH4 content exceeded 90%.
Another study focused on utilizing a robust strain that can withstand outdoor fluctuating conditions [85]. Tetradesmus obliquus was grown in diluted and bio-digested manure in an outdoor bioreactor to test the strain’s capability to upgrade biogas while treating the wastewater. The initial composition of desulphurized biogas was 57–63% CH4, 37–43% CO2, and <100 ppm H2S at a biogas flow rate of 1 L/min. After the purification process, the biogas contained 91% CH4, while the algae removed over 99% of both ammonia and phosphorus present in the manure.
Additionally, the study observed an increase in lipid production, highlighting the potential of algal strains to simultaneously upgrade biogas, remediate wastewater, and accumulate valuable compounds for biofuel production. Likewise, C. vulgaris (FACHB-31) was used for biogas upgrading and wastewater remediation using various carbon (C) to nitrogen (N) ratios at various TN and COD concentrations [78]. The pretreated biogas to which these strains were exposed contained 67.6% CH4, 28.4% CO2, 3.5% H2O, 0.47% O2, and <0.005% H2S. The authors reported that a 5:1 C/N ratio at 40 mg/L of TN was optimal for achieving a CH4 concentration of 93.6%. Moreover, the alga showed high nutrient removal: 77.6% of COD, 77.1% of TN, and 73% of TP.
However, despite the potential for using algal strains for both biogas upgrading and wastewater remediation, the current performance of algae still remains lower than that of conventional methods, which readily yield 88–98% CH4 [86]. Improvements in algal efficiency can be achieved with the use of acid-tolerant algal strains, which are naturally resilient to pH fluctuations and other cultivation stressors, thereby reducing the need for costly pH control. Furthermore, to enhance algal performance at scale, strain-improvement strategies such as genetic engineering and adaptive laboratory evolution (ALE) offer promising avenues for strengthening carbon utilization, nutrient uptake, and environmental tolerance [87].

4. Application of Acidophilic and Acid-Tolerant Algae in Wastewater Treatment

Recent studies have demonstrated the promising potential of acidophilic and acid-tolerant algae for the treatment of various types of acidic wastewater. These algal species, capable of thriving in low pH environments (pH = 0.5–5.0), have shown significant capabilities in removing heavy metals, nutrients, and toxic contaminants. Their resilience under harsh conditions, coupled with their ability to produce biomass suitable for biofuels or other applications, makes them attractive candidates for sustainable wastewater remediation.
Desmodesmus sp. MAS1 and Heterochlorella sp. MAS3, identified as acid-tolerant algae, were cultivated in flasks to evaluate their potential for heavy metal remediation and biodiesel production under acidic conditions [88]. The study employed a modified Bold’s Basal Medium (BBM) adjusted to pH 3.5, supplemented with Cu, Mn, and Zn at concentrations ranging from 0.5 to 20 mg/L and Fe ranging from 5 to 50 mg/L. Results demonstrated that both strains removed metals with efficiencies of 40–80% for Fe and 40–60% for Mn, along with significant uptake of Cu and Zn (Table 3). Biomass productivity was assessed via chlorophyll content, with production levels ranging between 0.27 and 4.0 relative fluorescence units (RFUs) per day. The biodiesel production potential from the algal biomass was evaluated using Fourier-transform infrared spectroscopy (FTIR), which revealed spectral regions consistent with aliphatic and long-chain hydrocarbon structures. These findings suggest that the biodiesel that could be produced would be rich in desirable monoalkyl esters. Moreover, cultivation in the presence of heavy metals enhanced biodiesel yield from 12 to 35%, likely due to biofilm formation and the accumulation of long-chain fatty acids.
G. sulphuraria, in addition to being acidophilic, is also a thermophilic and mixotrophic strain capable of thriving under extreme conditions, such as very low pH 0.5–4.0 and temperatures up to 56 °C [89]. Its potential for treating raw landfill leachate (LL) was initially explored using flask-scale cultivation, and later it was scaled up to a photobioreactor system operated at pH 2.5 [89]. Across eight experimental runs in the flasks, growth rates ranged from 0.074 to 0.19 g/L/day. The highest biomass concentration, 3.15 g/L, was achieved after 14 days of cultivation with 20% LL. Scale-up using a 5-L tubular bubbling column bioreactor cultivated for five cycles of 25 days showed that the growth rate of algae during these cycles ranged from 0.356 to 0.768 g/L/day (Table 3). The highest biomass concentration of 4.34 g/L was observed after the first cycle, followed by a gradual decline to 2.2 g/L in subsequent cycles. Despite the decrease in biomass over time, consistently high removal percentages (70–100%) of nitrogen and phosphate were observed in each run, indicating strong potential for nutrient removal and wastewater treatment. In another study, Galdieria phlegrea was examined for its ability to remove ammonium and phosphate from raw municipal wastewater at pH 2.5 [90]. Peak biomass concentration of 0.557 g/L after 9 days of cultivation was attained, which was comparable to cells grown under control conditions (Allen medium) at the same pH. Although nitrogen removal showed a slower trend (50%) within the first 24 h, the lipid content of the cells cultivated in wastewater doubled to 22% after just one day of cultivation, compared to the control. Moreover, a recent study explored the application of G. sulphuraria for the removal of the heavy metals cadmium (Cd) and Pb from aqueous solutions [91]. The alga was cultivated in synthetic wastewater using Cyanidium medium (CM), supplemented with 0–5 mg/L of Cd or Pb in the form of CdCl2 and PbCl2, respectively. Cultivation was conducted at a low pH of 2.5 under thermophilic conditions (40 °C) at a light intensity of 4000 lux. The highest growth rates were observed at 1.25 mg/L concentrations of Cd and Pb, reaching 0.331 g/L/day and 0.197 g/L/day, respectively, compared to control media which yielded 0.256 g/L/day (Cd) and 0.139 g/L/day (Pb). Notably, the highest removal efficiencies were achieved in media containing 2.5 mg/L of metal ions, with 49.8% removal for Cd and 25.1% for Pb. The corresponding sorption capacities were 1.45 mg/g and 0.53 mg/g of dry biomass, respectively. These findings were further validated in a follow-up study focused on Cd removal from synthetic aqueous solutions using a 10-day time-course experiment to distinguish between extracellular and intracellular Cd accumulation [92]. The study found no significant difference in growth rate between Cd-treated cells and the control group by day 10. However, G. sulphuraria maintained a higher growth rate when exposed to an initial Cd concentration of 1.5 mg/L compared to 6.0 mg/L, with final biomass concentrations of 1.38 g/L and 1.30 g/L, respectively. Across the tested Cd concentrations (1.5, 3.0, and 6.0 mg/L), Cd removal ranged from 18.88% to 30%, with corresponding sorption capacities between 0.63 mg/g and 1.59 mg/g of dry biomass. Importantly, the study revealed that Cd removal was primarily driven by non-metabolic processes, as intracellular Cd concentrations were significantly lower than the amount adsorbed onto the cell surface. G. sulphuraria was also used to recover low concentrations (<25 mg/L) of the precious metals gold (Au3+), palladium (Pd2+), and platinum (Pt4+) [93]. The cells were exposed to varying concentrations of HCl and low pH with metals ranging between 0.5 and 25 mg/L. The authors reported that at pH 2.5 and 40 mM hydrochloric acid, the algae were able to successfully remove 80% of Au3+ and Pd2+, while recovery of Pt4+ exceeded 60% at higher algal biomass concentrations (14 mg/mL). The study also exposed the algae to diluted wastewater containing precious metals and reported >90% removal of Au3+ and Pd2+. In another study, G. sulphuraria 074W (NIES-3638) was exposed to metals (AuCl3, H2PtCl6, and PdCl2) in a hydrochloric acid solution of either 5 mM at pH 2.3 or 500 mM at pH 0.3 [94]. Adsorption levels reached 98% for Au, 81% for Pd, and 67% for Pt in the 5 mM HCl solution.
In addition to commonly encountered heavy metals, rare earth elements (REEs), such as lanthanum (La3+), cerium (Ce3+), and neodymium (Nd3+), are emerging contaminants in aquatic systems due to their increased use and disposal across various industries [95]. To investigate algae’s potential to remediate them, REE-contaminated acidic water was used to cultivate Euglena gracilis CCALA 349 under heterotrophic conditions [96]. Cultivation was conducted in flasks with the medium adjusted to a pH below 4.5. La3+ was introduced as LaCl3 at concentrations ranging from 1 to 100 μM. For comparison, Al3+ (as AlCl3) and Fe3+ (as FeCl3) were added to separate flasks. As summarized in Table 3, after 96 h of cultivation, the dry biomass of E. gracilis treated with 100 μM La3+ reached 10.27 g/L, representing a 16.3% increase compared to the untreated control. Notably, 99.9% of the La3+ was successfully removed from the medium. Glucose consumption under heterotrophic conditions was also higher in La3+-treated cultures than in the control. A similar trend was observed in cultures treated with FeCl3 and AlCl3, indicating that REE treatment is comparable to other metal treatments and can enhance biomass production. Fatty acid profiling revealed that the cell content of saturated fatty acids (SFAs) was 55.60% on day 4, which significantly increased to 72.78% following wax ester fermentation on day 6. Given that biodiesel typically consists of hydrocarbons with chain lengths of 8–14 carbon atoms, an elevated SFA content suggests improved fuel quality potential. Taken together, the strategy of combining heterotrophic cultivation of E. gracilis with La3+ treatment followed by anaerobic wax ester fermentation presents a promising approach for simultaneously remediating La3+-contaminated water and producing high-quality biodiesel.
Sulfur is also a common contaminant in municipal and industrial effluents, originating from various industries, such as pharmaceutical production, leather tanning, and mining operations [97]. To address this issue in acid mine drainage (AMD), a study evaluated the performance of a revolving algal biofilm (RAB) reactor under low pH conditions (3.5–4) and high sulfate concentrations (1–4 g/L) [97]. The RAB system was initiated by inoculating an algal seed culture of C. vulgaris UTEX #265 into an open liquid reservoir and rotating the belt to facilitate biofilm formation. Over a three-week period, suspended algae gradually adhered to the belt surface, forming a stable biofilm, while BBM was periodically added to compensate for evaporative water loss. Although the biomass productivity was not specified, the RAB reactors achieved a sulfate removal efficiency of up to 46%, with a maximum removal rate of 0.56 g/Lday, which significantly outperformed traditional suspension algal cultures. At the end of the cultivation, high-throughput sequencing revealed a diverse microbial community within the RAB system, including cyanobacteria, green algae, diatoms, and acid-reducing bacteria, all contributing to sulfate removal through various biological mechanisms.
Another alga, Keratococcus rhaphidioides, isolated from Lake Caviahue, Neuquén, Argentina, under an extremely acidic environment of pH 3.0, demonstrated exceptional tolerance to low pH and elevated removal of metals, such as Fe, Al, and Mn, even when complexed with chelators, like fulvic acids and nitrilotriacetic acid [98]. To evaluate its potential for acid effluent bioremediation, cultivation experiments were conducted at various pH (2–7), light intensity (0–70 µmol photons m−2 s−1), nutrient sources, and metal concentrations. Under optimal conditions of continuous illumination at 12 µmol photons m−2 s−1, pH adjusted to 3–4 using sulfuric acid, and improved aeration with CO2, biomass productivity increased ten-fold in a 7-photobioreactor setup compared to flask cultures. Although Cu, Pb, Zn, Cd, and chromium (Cr) were below detection limits, Fe:P absorption on the cell wall showed a molar ratio of approximately 7:1.
The above findings emphasize the critical role of cultivation conditions, nutrient supplementation strategies, and reactor design in enhancing the efficiency of wastewater remediation by algae. To ensure that such bioremediation processes are not only effective but also environmentally sustainable, Life Cycle Assessment (LCA) should be employed. LCA can be used to evaluate the environmental impacts associated with a product or process throughout its entire life cycle, from raw material to final disposal [99]. By analyzing inputs, outputs, and potential environmental effects, LCA helps identify opportunities to reduce resource utilization, minimize emissions, and improve overall sustainability, making it a valuable tool for guiding the development of scalable and eco-friendly bioremediation systems. Given the complex and costly nature of acidic wastewater treatment, conducting an LCA for acidophilic algal systems is essential to assess their environmental and economic viability.
Table 3. Summary of studies using acidophilic and acid-tolerant strains for wastewater treatment.
Table 3. Summary of studies using acidophilic and acid-tolerant strains for wastewater treatment.
Algae UsedType of Acidic Water Used (Synthetic or Real)pHGrowth ConditionsBiomass ProductivityRemediated Potential (%) and HighlightsReferences
Desmodesmus sp. MAS1 and Heterochlorella sp. MAS3Modified BBM media with various heavy metals concentration3.530 mL flask cultivation; continuous light at 60 μmol m−2 s−10.27 to 0.4 relative fluorescence units per day;
12–20% biodiesel yield		Fe (40–80%), Mn (40–60%), Cu, Zn removal[88]
Galdieria sulphurariaSynthetic wastewater with Cd or Pb2.540 °C; 50 mL flask cultivation; continuous 4000 lux light for 7 days0.331 and 0.197 g/L day in 1.25 mg/L Cd and PbCd (49.8%), Pb (25.1%), in addition to nutrients removal[91]
Synthetic aqueous solution with Cd40 °C; 50 mL flask cultivation; 4000 lux light for 10days0.13–0.138 g/L dayCd removal (30%), 1.59 mg/g sorption[92]
Raw landfill leachate with additional nitrogen source42 °C; 50 mL flask cultivation; continuous light0.074 to 0.19 g/L dayNH4-N removal up to 100%, PO4-P removal up to 97.6%[89]
42 °C; 500 mL in Photobioreactor; 5-day cycles for 25 days0.356 to 0.768 g/L dayNH4-N removal up to 99.8%, PO4-P removal up to 100%[89]
Galdieria phlegrea ACUF 784.3Raw municipal wastewater37 °C; 700 mL flask cultivation; 45 µmol photons/m2/s0.557 g/L after 9 days50% ammonium and 20% phosphate were removed in 24 hr[90]
Keratococcus rhaphidioidesModified medium “A”3.0–4.08 °C; 7 L Photobioreactor; constant light at 80 µmol photons/m2/s for 34 days10-fold higher than flask culturepH increases to as high as 10 daily. 7:1 (Fe:P) absorption ratio[98]
Chlorella vulgaris UTEX # 265 with mixed algae and bacteriaSynthetic sulfate-containing wastewater3.5–4.025 °C; Revolving biofilm reactors; constant light at 130 µmol photons/m2/s for 4 weeksNot reportedSulfur removal up to 46%[97]
Euglena gracilis CCALA 349Modified Hutner medium with various REE concentration (LaCl3 at 0–100uM)≤4.5100 mL flask cultivation, dark10.27 g/L after 96 hr cultivation99.9% of REE removed[96]
G. sulphuraria 074WAltered Allen’s media 0.5–2.5Glass vessels at 42 °C
under constant light
at 70 μE/m2s		Not reportedRemoved 80% of Au3+ and Pd2+. And Pt4+ reached >60%[93]
0.3–2.350 mL glass vessels98% of cells adsorbed Au, 81% adsorbed Pd, and 67% adsorbed Pt[94]

5. Future Recommendations and Limitations

Although acidophilic and acid-tolerant algal strains show promise as a sustainable alternative for remediating acidic wastewater, several limitations hinder their commercial feasibility. A key challenge is the limited understanding of the cellular mechanisms that govern algal responses to mixed heavy metals and to organic and inorganic pollutants in acidic wastewater. Future work should focus on elucidating metal-binding mechanisms, identifying metal transporters involved in membrane uptake of heavy metals, and characterizing alterations to algal surface chemistry in response to acidic effluents. Gaining insights at the molecular level can help elucidate key pathways involved in regulating algal metabolism in response to low pH and in binding toxic metals, thus creating a foundation for optimizing culture conditions and engineering strains with higher biosorption and bioaccumulation capabilities.
To date, most of the literature focuses on utilizing controlled environments to test bioremediation of algae, thereby restricting the type and concentration of heavy metals and other toxic compounds examined [63,100]. However, real-world acidic wastewaters have a far more complex composition, including various types of metals and pollutants. To assess algal strains under conditions that more accurately represent real-world acidic streams and environmental fluctuations, recent studies have begun using synthetic acid mine drainage and raw effluents that more closely mimic industrial applications [33,51,90]. These studies have reported high removal of ammonium and phosphate [90] and efficient removal of Cd II, Ni II, Pb II, and Zn II [51] by algae [33]. Expanding from these results, the next steps to further examine the prospect of commercialization will be testing promising strains at larger, more commercially relevant scales. Understanding the effects of mixed metal exposure and additional pollutants within wastewater on cellular response will enable researchers to improve their assessments of prospective strains for practical applications. Given that acidophilic algal strains exhibit a trade-off between remediating metals and growth performance [14], broadening the understanding of how bioremediation mechanisms impact algal metabolism will be essential for performing lab-based adaptations and targeted strain improvement.
Emerging tools, such as adaptive laboratory evolution (ALE), Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR), and quantum computer modeling, show promise for advancing strain improvement in algae. ALE is a process that accelerates the natural evolution of a cell through prolonged progressive exposure to increasingly extreme conditions, such as acidic pH, the presence of heavy metals, and elevated salt content [101]. Through continuous growth cycles under such conditions, the cells adapt their mechanisms for increased tolerance [102]. Recently, a new strain of the cyanobacterium Synechocystis sp. PCC6803 was created via ALE. After growing in industrial wastewater, the strain demonstrated favorable bioremediation characteristics, such as removal of 35.55% of TN and 60.95% of TP, while maintaining a significant lipid content of 16.9% [103]. Additionally, another strain, Cyanidioschyzon merolae, was capable of thriving when exposed to Ni at a concentration of 10 mM after being subjected to ALE, whereas this strain originally suffered detrimental effects, such as apoptosis, when grown in concentrations of Ni as low as 3 mM [104]. This indicates the strong potential for using ALE when optimizing strain performance in extreme conditions. Furthermore, CRISPR is a technology that allows for selectively modifying genes and enabling favorable traits in strains through precise optimization [105]. This method has been used to engineer algal strains, but the enhanced strains need to be validated through large-scale studies that more robustly test the challenges they would encounter in real-world applications [106,107]. Omics analysis on such evolved strains is essential to unravel the genetic perturbations that lead to the adaptation of the alga to low pH environments. Omics can also aid in identifying novel genetic targets that can be engineered in the future for attaining even better-performing strains. In addition to gene editing tools, novel quantum computer modeling can help characterize DNA mutations and predict evolutionary changes within the cell’s genome [108]. This promising quantum approach—combined with the identification of the genetic and physiological processes using omic tools—could streamline the design of bioengineered algal strains and reduce reliance on lengthy trial-and-error mutagenesis procedures. Thus, instead of hoping to find a usable mutation, the quantum approach would suggest the best mutation options to increase algal yield, which then can be engineered using CRISPR.
Beyond strain engineering techniques, future research should also focus on strain bioprospecting and cultivation systems. By isolating strains from extreme (low pH) environments that already exhibit commercially favorable traits, such as low pH tolerance and high growth rate, strain development and cultivation time and costs can be reduced. Currently, cultivating algal strains is resource-intensive, as they heavily rely on light energy and nutrient supplementation for maximum growth [109]. Altering the cultivation method could reduce the demand for artificial lighting while relying more on wastewater ingredients as essential nutrients. When considering cultivation systems, closed photobioreactors have the advantage of providing a controlled environment that helps algae exhibit higher growth rates and biomass productivity [110]; however, the need for corrosion-resistant materials suitable for low pH operation significantly raises capital costs [14]. Open raceway ponds, on the other hand, enjoy lower capital and operating expenses than closed photobioreactors [111]. However, when algae grow outdoors in open raceway ponds, they are exposed to a higher risk of contamination and variable environmental conditions that lead to lower growth efficiency [112]. For this reason, isolating robust strains that can withstand the variability of outdoor conditions can lower resource demand and hence decrease the cost for cultivation [113,114]. In both open and enclosed systems, replacing some of the necessary nutrients with wastewater ingredients and CO2 from flue gas emissions can help reduce operating costs.
Importantly, coupling algal systems with traditional methods, such as electrochemical, membrane, or constructed wetland processes, could maximize pollutant removal efficiency and process stability. For example, a hybrid electrochemical–algal system could first apply electrocoagulation, using electrical energy to remove suspended solids, as a pretreatment step, followed by the use of acid-tolerant algae for improved metal, nutrient, and organic compound removal via adsoprtion.
It should be noted that following the remediation of acidic effluents, the residual metal-laden algal biomass must be carefully handled to prevent secondary pollution. The lipids and carbohydrates in the biomass could be extracted for biodiesel and bioethanol/biogas production, respectively. Moreover, algal biomass generated from acidic effluents with relatively low metal load, such as wastewater generated from food and beverage industries, fermentation industries, and natural acidic waters, could serve as a biofertilizer or soil amendment. For wastewater streams rich in metals, future research should explore metal recovery from the algal cells using green solvents, such as mild acids, chelating agents, or biosurfactants, so that metal-free algal biomass can potentially find uses in bioenergy, biofertilizer, or biochar applications.

6. Conclusions

Acidophilic and acid-tolerant algae hold significant potential for the remediation of various acidic effluents, particularly where conventional techniques are ineffective, thanks to their inherent ability to thrive at low-pH, adsorb or absorb heavy metals, and metabolize inorganic and organic forms of nitrogen, phosphorus, and other organic pollutants present in such wastewaters. While remediating toxic and recalcitrant acidic effluents, algae produce valuable biomass that can be valorized for biofuels, biofertilizers, and other biosorption-derived products, thereby improving the overall economics of bioremediation. Despite their promising potential compared to conventional techniques, such as chemical precipitation, algae are slower to remove metals, so scaling up to industrial volumes requires significant reactor optimization. Moreover, due to the limited number of studies reported to date on low pH-resilient algae and the lack of large-scale data on metal uptake kinetics, pilot studies are needed to predict the long-term stability of algal remediation. To overcome these challenges, more research on bioprospecting and engineering robust algae, optimizing cultivation parameters, and even developing algae-bacteria consortia are essential to realize the full potential of acidophilic algae. Comprehensive surveys of acidic environments, including AMD, geothermal springs, and industrial acidic effluents, could lead to discovery of natural algal species with superior metal tolerance and/or biosorption capabilities. To transition from lab to industrial scale, LCA and Techno-Economic Analysis (TEA) are crucial to assess the sustainability and economic feasibility of algal treatment, respectively, and help optimize large-scale deployment by integrating algae-based bioremediation into existing wastewater treatment technologies. Indeed, to make algae commercialization a reality, valorization of the algal biomass is essential, whereby waste is not just treated and discarded, but rather transformed into value-added materials that enhance process economics and advance a circular economy. Lastly, collective efforts in policy and regulatory frameworks should prioritize incentives that accelerate the use and adoption of biobased remediation. Coupling environmental regulations with research and development funding can help overcome technological gaps for effectively mitigating acid wastewater using algae.

Author Contributions

P.S., N.A., D.S.-A. and G.P.P. conceptualized the manuscript; P.S., E.L. and N.A. prepared the original draft of the article; N.A., D.S.-A. and G.P.P. reviewed and edited the article; P.S. and E.L. visualized the figures and tables in the manuscript; N.A., D.S.-A. and G.P.P. supervised and were responsible for project administration. All authors have read and agreed to the published version of the manuscript.

Funding

This research was partially supported by the Patel College of Global Sustainability at the University of South Florida and by USF startup funds to D.S.-A.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

All data are available and can be located within the manuscript.

Acknowledgments

The figures were created in BioRender. Available online: https://BioRender.com/52e1zjr (accessed on 19 December 2025).

Conflicts of Interest

The authors declare no conflicts of interest.

Abbreviations

The following abbreviations are used in this manuscript:
ALEAdaptive laboratory evolution
CH4 Methane
ABC transportersATP-binding cassette transporters
ALAluminum
BBMBold’s Basal Medium
CCarbon
CdCadmium
Ce3+Cerium
CMCyanidium medium
CO2 Carbon dioxide
CODChemical oxygen demand
CrChromium
CRISPRClustered Regularly Interspaced Short Palindromic Repeats
CTRCopper transporters
Cu Copper
FeIron
FTIRFourier-transform infrared spectroscopy
FTRIron transporters
La3+Lanthanum
LCALife cycle assessment
LLLandfill leachate
Mn Manganese
NNitrogen
Na Sodium
Nd3+Neodymium
NiNickel
NRAMPNatural resistance-associated macrophage proteins
PbLead
RAB Revolving algal biofilm
REEsRare earth elements
RFUs Relative fluorescence units
SFAsSaturated fatty acids
TEATechno-economic analysis
TNTotal nitrogen
TPTotal phosphorus
ZnZinc

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Applsci 16 00216 g001
Figure 1. Mechanism of wastewater remediation within the algal cell. Functional groups present on the cell surface (carboxyl, sulfate, amino, phosphate, hydroxyl, and amines) bind cationic metal ions, such as Fe, Na, and Cu, through electrostatic attraction, ion exchange, or complex formation. After entry into the cell, the metal ions are chelated by metallothionine, phytochelatin, or glutathione before being shuttled into a vacuole or transported out of the cell. NRAMP: natural resistance-associated macrophage proteins; FTR: iron transporters; CTR: copper transporters; ZRT/ZIP: ZRT/IRT-like proteins; ABC: ATP-binding cassette transporters; HM: heavy metal ions.
Figure 1. Mechanism of wastewater remediation within the algal cell. Functional groups present on the cell surface (carboxyl, sulfate, amino, phosphate, hydroxyl, and amines) bind cationic metal ions, such as Fe, Na, and Cu, through electrostatic attraction, ion exchange, or complex formation. After entry into the cell, the metal ions are chelated by metallothionine, phytochelatin, or glutathione before being shuttled into a vacuole or transported out of the cell. NRAMP: natural resistance-associated macrophage proteins; FTR: iron transporters; CTR: copper transporters; ZRT/ZIP: ZRT/IRT-like proteins; ABC: ATP-binding cassette transporters; HM: heavy metal ions.
Applsci 16 00216 g001
Table 1. Sources of acidic wastewater, their pH range, and metal composition.
Table 1. Sources of acidic wastewater, their pH range, and metal composition.
Type of Acidic Wastewater pH Range Metal Composition Reference
Mining and ore processing 1.0–3.0 Hg2+, Cr6+, Cu2+, Ni2+, Mn2+, Fe2+, Cd2+, Zn2+, Pb2+, As+3/As+5, Sb+3/Sb+5, Au+3 [7]
Acid mine drainage 2.0–4.5 Al3+, Fe2+/Fe3+, Mg2+, Cu2+, Mn2+, Zn2+ [6]
Acidic leachates 1.9–5.5 Cu2+, Ni2+, Mn2+, Fe2+, Cd2+, Zn2+, Pb2+ [8]
Metal smelting 2.0–4.5 Pb2+, Cd2+, As+3/As+5, Cr6+[9,10]
Phosphate fertilizer industry 1.5–4.0 Fe2+, Ni2+, Zn2+, Cr3+, Al3+, As+3/As+5, Cd2+, V [11,12]
Acidic dye wastewater 3.0–5.0 Pb2+, Cd2+, Zn2+, Hg2+, Cr6+, Cu2+, Fe2+ [13]
Hg: mercury; Cr: chromium; Cu: copper; Ni: nickel; Mn: manganese; Fe: iron; Cd: cadmium; Zn: zinc; Pb: lead; As: arsenic; Sb: antimony; Au: gold; Al: aluminum; V: vanadium.
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Slick, P.; Arora, N.; Lo, E.; Santiago-Alarcon, D.; Philippidis, G.P. Prospects of Algal Strains for Acidic Wastewater Treatment. Appl. Sci. 2026, 16, 216. https://doi.org/10.3390/app16010216

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Slick P, Arora N, Lo E, Santiago-Alarcon D, Philippidis GP. Prospects of Algal Strains for Acidic Wastewater Treatment. Applied Sciences. 2026; 16(1):216. https://doi.org/10.3390/app16010216

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Slick, Paulina, Neha Arora, Enlin Lo, Diego Santiago-Alarcon, and George P. Philippidis. 2026. "Prospects of Algal Strains for Acidic Wastewater Treatment" Applied Sciences 16, no. 1: 216. https://doi.org/10.3390/app16010216

APA Style

Slick, P., Arora, N., Lo, E., Santiago-Alarcon, D., & Philippidis, G. P. (2026). Prospects of Algal Strains for Acidic Wastewater Treatment. Applied Sciences, 16(1), 216. https://doi.org/10.3390/app16010216

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