Algicidal Efficiency Research Articles

Algicidal activity synchronized with nitrogen removal by actinomycetes: Algicidal mechanism, stress response of algal cells, denitrification performance, and indigenous bacterial community co-occurrence

The harmful algal blooms (HABs) can damage the ecological equilibrium of aquatic ecosystems and threaten human health. The bio-degradation of algal by algicidal bacteria is an environmentally friendly and economical approach to control HABs. This study applied an aerobic denitrification synchronization algicidal strain Streptomyces sp. LJH-12–1 (L1) to control HABs. The cell-free filtrate of the strain L1 showed a great algolytic effect on bloom-forming cyanobacterium, Microcystis aeruginosa (M. aeruginosa). The optimal algicidal property of strain L1 was indirect light-dependent algicidal with an algicidal rate of 85.0%. The functional metabolism, light-trapping, light-transfer efficiency, the content of pigments, and inhibition of photosynthesis of M. aeruginosa decreased after the addition of the supernatant of the strain L1 due to oxidative stress. Moreover, 96.05% nitrate removal rate synchronized with algicidal activity was achieved with the strain L1. The relative abundance of N cycling functional genes significantly increased during the strain L1 effect on M. aeruginosa. The algicidal efficiency of the strain L1 in the raw water was 76.70% with nitrate removal efficiency of 81.4%. Overall, this study provides a novel route to apply bacterial strain with the property of denitrification coupled with algicidal activity in treating micro-polluted water bodies.

Boosting algicidal efficiency of Alteromonas sp. FDHY-CJ against Skeletonema costatum through fermentation optimization

Algicidal bacteria exhibit promising potential against harmful algal blooms (HABs); however, their application has been limited due to their limited algicidal activity. This study demonstrates the enhanced algicidal activity of Alteromonas sp. FDHY-CJ bacteria against harmful Skeletonema costatum using a 5 L fermenter. Utilizing this refined framework increased the OD600 value and algal cell mortality by 6.50 and 2.88 times, respectively, compared to non-optimized culture cultivated in a flask using marine broth 2216E medium. The mechanism of action involves significant inhibition of algal photosynthetic efficiency with concurrent degradation of photosynthetic pigments. Relative to the non-optimized group, the optimized bacterial treatment led to a significant increase in H2O2 and MDA (malondialdehyde) by 19.54 and 4.22-fold, respectively, and resulted in membrane damage. The culture optimization procedure yielded effectual algicidal substances capable of considerably reducing the severity of S. costatum HABs through cell membrane disruption.

Bacillus cereus strain L7 lyses Cylindrospermopsis raciborskii through intercellular contact

Cylindrospermopsis raciborskii is a new type of toxic filamentous cyanobacteria commonly found in tropical regions but has recently spread to temperate areas. It is considered an invasive species that poses a serious threat to drinking water sources and human health. Bacillus cereus strain L7, previously isolated and identified by our group, was found to have efficient algicidal activity against C. raciborskii FACHB-1503 in this study. The growth period and initial concentration of L7 had a significant impact on algicidal activity, with L7 culture in the decline phase exhibiting the highest algicidal activity (I = 99.62 %). The ideal environmental conditions for the coculture system were 30 °C, pH = 8, and a light-dark cycle (12 h light: 12 h dark). In experiments to confirm the algicidal mode of L7, the pellet resuspension with R2A medium had the highest algicidal efficiency (I = 98.54 %, t = 6 d), even higher than that of the L7 culture. In contrast, sterile filtrate and pellet resuspension with sterile water had no discernible impact on the algal growth, indicating that L7 performed algicidal activity through direct contact with algal cells. Following 6 days of coculture of L7 culture with C. raciborskii solution, the activity of the PSII system and the photosynthetic efficiency of algal cells were both zero. Following SEM and TEM results, it was discovered that the process of L7 lysis of algal cells begins with the disruption of their multicellular filamentous structure, rupture of the cell wall, efflux of the cell contents, and complete disappearance of the algal cell structure. This is the first research to demonstrate that L7 lyses C. raciborskii directly, which serves as an excellent strategic direction for launching innovative freshwater bloom control strategies.

Discovery of a High-Efficient Algicidal Bacterium against Microcystis aeruginosa Based on Examinations toward Culture Strains and Natural Bloom Samples.

Harmful cyanobacterial blooms occur worldwide and pose a great threat to aquatic ecosystems and public health. The application of algicidal bacteria represents an eco-friendly strategy for controlling harmful cyanobacterial blooms; thus, searching for a high efficiency of algicidal bacteria has been becoming an important and continuous task in science. Herein, we identified a bacterial strain coded Streptomyces sp. HY with a highly algicidal activity, and investigated its algicidal efficiency and mechanism against Microcystis aeruginosa. The strain HY displayed high algicidal activity toward Microcystis aeruginosa cells, with a removal rate of 93.04% within 2 days via indirect attack. Streptomyces sp. HY also showed the ability to lyse several genera of cyanobacterial strains, including Dolichospermum, Pseudanabaena, Anabaena, and Synechocystis, whereas it showed a minor impact on the green alga Scenedesmus obliquus, demonstrating its selectivity specially for targeting cyanobacteria. Its algicidal mechanism involved damages to the photosynthesis system, morphological injury of algal cells, oxidative stress, and dysfunction of the DNA repair system. Furthermore, HY treatment reduced the expression levels of genes (mcyB and mcyD) related to microcystin biosynthesis and decreased the total content of microcystin-leucine-arginine by 79.18%. Collectively, these findings suggested that the algicidal bacteria HY is a promising candidate for harmful cyanobacterial bloom control.

A novel algicidal bacteria isolated from native snail lived in Taihu Lake against algal blooms: identification, degradation kinetic, and algicidal mechanism.

Harmful algal blooms (HABs) impacted negatively the water ecosystem, and produced toxic microcystins that poses toxic effect on liver, nervous, and genital system. The introduction of useful and adaptive algae-degrading microbes or bio-augmentation can be regarded as an efficient way to inhibit the outbreak of HABs. The purpose of this study is to evaluate the application potential of algicidal bacteria named XMC, which is isolated from native snails. Response surface methodology (RSM) experiments showed that self-characteristic and various external conditions affected the actual algae inhibition ability of XMC. In particular, actual algicidal efficiency was strongly depend on the temperature and growth stage of XMC, and the maximum algicidal rate could reach 93.95% within 7days. The degradation curve of Microcystis aeruginosa was compliant with the first-order kinetic model, which could be used to predict the degradation effect of Microcystis aeruginosa in engineering applications. The analysis results of algae dissolution products showed that algicidal bacteria XMC had both direct and indirect algicidal capacity. In addition, XMC had strong algicidal ability and greater environmental adaptability, and its algae dissolution products were environmentally friendly. All results indicated that XMC had the potential to be used in the bio-degradation of cyanobacteria bloom.

Identification and Optimization of the Algicidal Activity of a Novel Marine Bacterium Against Akashiwo sanguinea

Akashiwo sanguinea is a marine algal species associated with harmful algal blooms (HABs). We found that Vibrio brasiliensis H115, isolated from the seawater of Dameisha Bay (Shenzhen), China, can lyse A. sanguinea. At bacteria-to-algae cell ratios of 7,000:1 and 8,000:1, 73.9 ± 1.8 and 81.4 ± 2.8%, respectively, of A. sanguinea were lysed in just 10 min. V. brasiliensis H115 attacks A. sanguinea by secreting extracellular active compounds. Single-factor experiments showed that the optimum growth conditions for strain H115 were medium 2216E with extra sorbitol (1.0%) and peptone (2.0%), pH 7.5, a shaking speed of 200 rpm, and incubated at 40°C for 54 h. Under these optimized conditions, the algicidal efficiency of strain H115 against A. sanguinea improved by 69.4%. Large biomasses were obtained when strain H115 was incubated in 5- and 100-L bioreactors, with algicidal efficiencies against A. sanguinea reaching 94.2 ± 0.5 and 97.1 ± 0.6%, respectively, in 4 h of co-incubation. These results suggest that strain H115 and its active algicidal compounds may be viable for controlling the outbreaks of A. sanguinea.

Algicidal Properties of Microbial Fermentation Products on Inhibiting the Growth of Harmful Dinoflagellate Species

The fermentation processes of algicidal bacteria offer an eco-friendly and promising approach for controlling harmful algae blooms (HABs). The strain Ba3, previously isolated and identified as Bacillus sp., displays robust algicidal activity against HABs dinoflagellate in particular. Microbial fermentation products have also been found to provide metabolites with multiple bioactivities, which has been shown to reduce harmful algae species’ vegetative cells and thus reduce red tide outbreaks. In this study, the microbial fermentation of algicidal bacterium Ba3 was analyzed for its potential ability of algicidal compounds. A treatment time increased the algicidal efficiency of the fermentation products against Prorocentrum donghaiense (91%) and Alexandrium tamarense (82%). Among the treatment groups, the changing trend for the 2% treatment group was faster than that for the other treatments, showing that the inhibition rate could reach 99.1% in two days. Active components were separated by organic solvent extraction and macroporous resin, and the molecular weight of the active components was analyzed by LC-MS. The result shows that the microbial fermentation products offer a potential, not practical use for controlling the outbreaks of dinoflagellate blooms. As a result of its potential application for inhibiting HABs, these findings provide an encouraging basis for promoting large-scale fermentation production and the controlling the outbreaks of red tide.

Algicidal mechanism of Raoultella ornithinolytica against Microcystis aeruginosa: Antioxidant response, photosynthetic system damage and microcystin degradation

Water eutrophication caused by harmful algal blooms (HABs) occurs worldwide. It causes huge economic losses and has serious and potentially life-threatening effects on human health. In this study, the bacterium Raoultella sp. S1 with high algicidal efficiency against the harmful algae Microcystis aeruginosa was isolated from eutrophic water. The results showed that Raoultella sp. S1 initially flocculated the algae, causing the cells to sediment within 180 min and then secreted soluble algicidal substances that killed the algal cells completely within 72 h. The algicidal activity was stable across the temperature range −85.0 to 85.0 °C and across the pH range 3.00–11.00. Scanning electron microscopy (SEM) revealed the crumpling and fragmentation of cells algal cells during the flocculation and lysis stages. The antioxidant system was activated under conditions of oxidative stress, causing the increased antioxidant enzymes activities. Meanwhile, the oxidative stress response triggered by the algicidal substances markedly increased the malondialdehyde (MDA) and glutathione (GSH) content. We investigated the content of Chl-a and the relative expression levels of genes related to photosynthesis, verifying that the algicidal compounds attack the photosynthetic system by degrading the photosynthetic pigment and inhibiting the expression of key genes. Also, the results of photosynthetic efficiency and relative electric transport rate confirmed that the photosynthetic system in algal cells was severely damaged within 24 h. The algicidal effect of Raoultella sp. S1 against Microcystis aeruginosa was evaluated by analyzing the physiological response and photosynthetic system impairment of the algal cells. The concentration of microcystin-LR (MC-LR) slightly increased during the process of algal cells ruptured, and then decreased below its initial level due to the biodegradation of Raoultella sp. S1. To further investigate the algicidal mechanism of Raoultella sp. S1, the main components in the cell-free supernatant was analyzed by UHPLC-TOF-MS. Several low-molecular-weight organic acids might be responsible for the algicidal activity of Raoultella sp. S1. It is concluded that Raoultella sp. S1 has the potential to control Microcystis aeruginosa blooms.

Encapsulation and Algicidal Properties of Fermentation Products From Vibrio brasiliensis H115

Algicidal bacteria offer an eco-friendly and promising approach for controlling harmful algae blooms (HABs). In this study, repeated batch fermentation of immobilized algicidal bacterium Vibrio brasiliensis H115 was preformed to enhance the productivity of the algicidal compounds. The highest algicidal efficiency of the fermentation products against Akashiwo sanguinea (100%) was achieved when the fermentation time was decreased from 24 to 14 h. The cell-free fermentation broth was then spray-dried and floating microcapsules were prepared from the dried powder. The optimum preparation conditions for floating microcapsules were: sodium alginate (SA), 3%; CaCO3: SA (mass ratio), 3:4; CaCl2, 3%; citric acid, 4%; ethylcellulose, 2%; crosslinking time, 30 min. Under the optimal conditions, the floating microcapsules displayed efficient A. sanguinea cell lysis ability and the algicidal efficiency increased from 10.62% (4 h) to 100% (24 h). These results suggest that the floating microcapsules could potentially be practically used for controlling the outbreaks of A. sanguinea.

Algicidal Efficiency and Genotoxic Effects of Phanerochaete chrysosporium against Microcystis aeruginosa.

Eutrophication has become a severe environmental problem. This study evaluated the algicidal efficiency and genotoxic effects of Microcystis aeruginosa co-cultured with Phanerochaete chrysosporium for 48 h under the optimum conditions of 250 mg/L of P. chrysosporium at 25 °C with dissolved oxygen content of 7.0 mg/L. The results showed that the activity of algal dehydrogenase, superoxide dismutase, and peroxidase were all decreased and the malondialdehyde content increased after co-culturing. Fourier transform infrared spectroscopy and scanning electron microscopy observations showed that the functional group and structure of algal cells were significantly changed. Compared with those of control tadpoles, blood cells of Fejervarya multistriata tadpoles had increased micronucleus frequency (from 1.05 ± 0.09 to 1.99 ± 0.05) and abnormal nuclei (from 2.45 ± 0.06 to 5.83 ± 0.07). The tail length of M. aeruginosa co-cultured with P. chrysosporium increased from 1.12 ± 0.21 to 21.68 ± 0.34, and the comet length increased from 6.45 ± 0.09 to 36.45 ± 0.67 within 48 h. Micronucleus assay and Comet assay results demonstrated that P. chrysosporium might effectively remove algae and reduce genotoxic effects and may be safe for aquatic ecosystems.

The complete genome sequence of the algicidal bacterium Bacillus subtilis strain JA and the use of quorum sensing to evaluate its antialgal ability

We describe the isolation of Bacillus subtilis strain JA and demonstrate that this bacterium exhibited strong algicidal effects on the algae Alexandrium minutum with an inhibition rate exceeding 80 % within 48 h. B. subtilis JA significantly reduced the photosynthetic efficiency of A. minutum and caused extensive morphological damage to the algae. Genomic analysis of B. subtilis JA demonstrated that a putative AI-2 type quorum sensing (QS) gene (LuxS) is present in its genome cluster, which is regulate pheromone biosynthesis. Interestingly, the exogenous addition of a QS-oligopeptide (ComX-pheromone) improved the algicidal efficiency of B. subtilis JA, thus indicating that the algicidal activity of this bacterium is potentially regulated by QS. Collectively, our data describe a potential antialgal bacterium and speculated that its behavior can be modulated by QS signal. B. subtilis JA may therefore represent a valuable tool for the development of novel chemical-ecological methods with which to control harmful algae.

Physiological responses of Microcystis aeruginosa against the algicidal bacterium Pseudomonas aeruginosa

Proliferation of cyanobacteria in aquatic ecosystems has caused water security problems throughout the world. Our preliminary study has showed that Pseudomonas aeruginosa can inhibit the growth of cyanobacterium, Microcystis aeruginosa. In order to explore the inhibitory mechanism of P. aeruginosa on the cell growth and synthesis of intracellular substances of M. aeruginosa, concentrations of Chlorophyll-a, intracellular protein, carbohydrate, enzyme activities and ion metabolism of M. aeruginosa, were investigated. The results indicated that 83.84% algicidal efficiency of P. aeruginosa was achieved after treatment for 7 days. The strain inhibited the reproduction of M. aeruginosa by impeding the synthesis of intracellular protein and carbohydrate of cyanobacterium, and only a very small part of intracellular protein and carbohydrate was detected after exposure to P. aeruginosa for 5 days. P. aeruginosa caused the alteration of intracellular antioxidant enzyme activity of M. aeruginosa, such as catalase, peroxidase. The accumulation of malondialdehyde aggravated membrane injury after treatment for 3 days. P. aeruginosa also affected the ion metabolism of cyanobacteria. The release of Na+ and Cl− was significantly enhanced while the uptake of K+, Ca2+, Mg2+, NO3− and SO42− decreased. Surface morphology and intracellular structure of cyanobacteria and bacterial cells changed dramatically over time as evidenced by electron microscope (SEM) and transmission electron microscope (TEM) analysis. These results revealed that the algicidal activity of P. aeruginosa was primarily due to the fermentation liquid of P. aeruginosa that impeded the synthesis of intracellular protein and carbohydrate, and damaged the cell membrane through membrane lipid peroxidation.

Algicidal efficiency and mechanism of Phanerochaete chrysosporium against harmful algal bloom species

Algal blooms pose serious ecological problems, threaten biological safety, and cause great economic losses. While white-rot fungi have attracted worldwide attention for their ability to inhibit algal blooms, the algicidal efficiency and mechanism of Phanerochaete chrysosporium have not been reported to date. In this study, Cryptomonas obovata FACHB-1301, Oscillatoria sp. FACHB-1083, and Scenedesmus quadricauda FACHB-507 were co-cultured with P. chrysosporium under optimum conditions with a fungal dosage of 250mg−l, pH of 7.0 and dissolved oxygen content of 7.0mg−l. The results showed that the chlorophyll-a content, dehydrogenase activity, and soluble protein content of the three algae decreased, whereas the malondialdehyde content increased after 48h of co-culture. Flow cytometry showed that P. chrysosporium damaged the membranes and nucleic acid of the algal cells, thereby causing cell death. Fourier transform infrared spectroscopy results indicated that the pyrrole ring of chlorophyll-a was degraded, and scanning electron microscopy revealed that the structure of the algal cells was seriously damaged by P. chrysosporium. These results demonstrated that the algal cells were severely damaged by P. chrysosporium and were finally degraded directly by the fungus, which has superior properties as algicidal agent for its low cost and safety compared to physical and chemical methods.

Wheat Bran Enhances the Cytotoxicity of Immobilized Alcaligenes aquatilis F8 against Microcystis aeruginosa.

Algicidal bacteria offer a promising option for killing cyanobacteria. Therefore, a new Alcaligenes aquatilis strain F8 was isolated to control Microcystis aeruginosa in this study. The algicidal activity of strain F8 was dependent on the cell density of M. aeruginosa, and the maximal algicidal rate of the free bacterium reached 88.45% within 72 h. With a view to its application to the control of M. aeruginosa in the natural environment, strain F8 was immobilized in sodium alginate beads, but immobilization of the strain decreased its algicidal rate compared to that of the free bacterium. However, addition of wheat bran to the sodium alginate matrix used to immobilize strain F8 not only eliminated the adverse effects of immobilization on the bacteria but also resulted in an 8.83% higher algicidal rate of the immobilized than free bacteria. Exclusion and recovery methods were used to identify key ingredients of wheat bran and gain insight into the mechanism underlying the observed enhancement of algicidal activity. This analysis indicated that certain factors in wheat bran, including vitamins B1, B2, B9, and E were responsible for promoting bacterial growth and thereby improving the algicidal rate of immobilized strain F8. Our findings indicate that wheat bran is able to improve the algicidal efficiency of A. aquatilis strain F8 for killing M. aeruginosa and is a good source of not only carbon and nitrogen but also vitamins for bacteria.

Growth inhibition and microcystin degradation effects of Acinetobacter guillouiae A2 on Microcystis aeruginosa

Strain A2 with algicidal activity against Microcystis aeruginosa was isolated and identified with the genus Acinetobacter on the basis of phenotypic tests and 16S rRNA gene analysis. It was identified with the species Acinetobactor guillouiae by partial rpoB sequence analysis. When 10% (v/v) of the bacterial culture was co-incubated with M. aeruginosa culture, algicidal efficiency reached 91.6% after 7 days. Supernatant of A2 culture showed similar algicidal activity, while the cell pellet had little activity, suggesting that Acinetobacter guillouiae A2 indirectly attacked M. aeruginosa cells by secreting an extracellular algicidal compound, which was characterized as heat-stable. A significant decrease in the microcystin (microcystin-LR) concentration was observed after 10% (v/v) addition of A2 culture. Transcription of three microcystin-related genes (mcyA, mcyD and mcyH) was also found to be inhibited. The algicidal compound 4-hydroxyphenethylamine was obtained by further isolation and purification using various chromatographic techniques. The EC50, 3d and EC50, 7d values of 4-hydroxyphenethylamine against M. aeruginosa were 22.5 and 10.3 mgL−1, respectively. These results indicate that A. guillouiae strain A2 inhibits growth of M. aeruginosa and degrades microcystin production. The identified compound, 4-hydroxyphenethylamine, has potential for development as a new algicidal formulation or product.

Interactive effects of algicidal efficiency of Bacillus sp. B50 and bacterial community on susceptibility of Microcystis aeruginosa with different growth rates

Application of algicidal bacteria is a promising way in the control of harmful algal blooms. However, many environmental factors can strongly influence the algicidal efficiency of algicidal bacteria against harmful algae. Till now, the relationship between algicidal efficiency and environmental factors is still elusive. In order to explore the key factors which play important role in determining the algicidal efficiency of an algicidal bacterium Bacillus sp. B50 against Microcystis aeruginosa, the susceptibilities of thirteen M. aeruginosa strains to algicidal bacterium Bacillus sp. B50 were tested. The results indicated that these thirteen M. aeruginosa strains could be classified into three groups: high susceptive strains, moderate susceptive strains and, resistant ones. The susceptibility of these Microcystis strains to Bacillus sp. B50 did not correspond with microcystins-producing characteristics or cellular phenotype of M. aeruginosa. However, the susceptibility has a linear relationship with growth rate of these M. aeruginosa strains. Bacterial community in the culture of the resistant strains could modify the susceptibility of susceptive one to the stress from algicidal bacterium, but this modification could be diminished by enhancing inoculation density of algicidal bacterium.

Isolation and algicidal effect of algicidal bacterium strain N25

Objective To isolate high efficient algicidal bacteria,and investigate their algicidal effect on Microcystis aeruginosa. MethodsBacteria were isolated from activated sludge,and were inoculated in Microcystis aeruginosa culture fluid.Algicidal bacteria were screened through observation of color of culture fluid and number of Microcystis aeruginosa.Algicidal efficiency was evaluated by calculating the algicidal rates,and high efficient algicidal bacteria were obtained.PCR was employed to sequence 16S rDNA of high efficient algicidal bacteria,and was aligned with the data of Genebank to identify the target bacterium.Transmission electronic microscopy was used to observe the morphological changes in the algae treated with algicidal bacteria for 48 h. ResultsA strain of algicidal bacterium was isolated from activated sludge samples,which was designated as N25-2(hereinafter to be referred as N25).It was identified by 16S rDNA that the match rates of N25 with Bacillus SP.and Lysinibacillus fusiformis were both 99%.When the concentration of Microcystis aeruginosa was over 1×106/mL and the concentration of bacteria reached 1×106 cfu/mL,the algicidal rate was higher than 72% within 48 h.Transmission electronic microscopy revealed that there were increased vacuoles,deep staining of polyhedrons and increased phycobilisomes in Microcystis aeruginosa after being treated with N25,and the main morphological changes were plasmolysis and inner structural damage. ConclusionN25 has a high algicidal efficiency,and the algicidal mechanism may be associated with the secretion of bacteria,which needs further study.

Inhibition of Microcystis aeruginosa and microcystin-LR with one algicidal bacterium isolated from a eutrophic lake

Toxic Microcystis aeruginosa blooms have been increased in freshwater body in China in recent years. The discovery of algicidal bacteria has brought renewed attention in the treatment of the harmful algae blooms (HABs). In this study, one strain of algicidal bacterium number SDK2 was selected from a eutrophic lake and its inhibition effects on M. aeruginosa and microcystin-LR released by M. aeruginosa was studied. The algicidal activity showed that the strain SDK2 had significant algicidal efficiency on M. aeruginosa. The removal rate of chlorophyll a increased when the bacterial cell density increased and it reached a maximum of 80%. It inhibited M. aeruginosa indirectly by releasing extracellular algicidal matter. It also had good degradation effects on microcystin-LR and the removal rate was 65%. According to the physiological and biochemical characteristics and the16S rDNA sequencing analysis of the strain SDK2, it was identified as Ochrobactrum sp. Key words : Removal, Microcystis aeruginosa , microsystins, algicidal bacterium.

The Algicidal Characteristics of One Algae-Lysing FDT5 Bacterium on Microcystis aeruginosa

One strain of algicidal bacterium which can inhibit Harmful algal blooms (HABs), FDT5, was isolated from activated sludge and found to have good algicidal effects on Microcystis aeruginosa. It was revealed that: The FDT5 was a Gram-negative bacterium and identified as Ochrobactrum sp.; The greater the initial bacterial cell density, the faster the degradation of chlorophyll a.; The algicidal efficiency was evaluated at the most favorable conditions which were a temperature of 30–35°C, a pH of 7.6 and complete darkness; The FDT5 strain lysed Microcystis aeruginosa not directly but by secreting metabolites which could withstand high temperatures and pressure.

Influence of Stabilizer Concentration on Effectiveness of Chlorine as an Algicide

Cyanuric acid, used as chlorine stabilizer in swimming pool waters, has a relatively minor effect on the algicidal efficiency of free chlorine. The toxicity of free chlorine to three swimming pool algae was reduced slightly by 25 mg of cyanuric acid per liter if inhibiting, but less than algicidal, concentrations of chlorine were employed. Higher stabilizer concentrations (50, 100, and 200 mg/liter) generally resulted in no further reduction in the algicidal efficiency of free chlorine beyond that observed at 25 mg/liter.