Antialgal Properties Research Articles

Green slag cement with nano copper oxide and nano silica: Enhanced antimicrobial and structural properties

The global construction industry is facing challenges related to sustainability, environmental impact, and the demand for innovative materials with multifunctional properties. A major concern is the durability of cement structures, which is often compromised by harmful bacteria and algae. These microorganisms accelerate the deterioration of structures, increase maintenance costs, and pose safety risks. Addressing these issues is essential to prolong the life of cement-based structures and reduce their environmental and carbon footprint. Cement in moist environments is particularly vulnerable to microbial growth, leading to structural weaknesses and degradation. This degradation necessitates costly repairs, shortens the lifespan of infrastructure, creates a threat to human lives, and contributes to increased carbon emissions. To tackle these challenges, researchers have tried to develop low-carbon cement ((green cement) with antimicrobial properties. Nanomaterials like nano-copper oxide (nCuO) and nano-silica (nSiO₂) have shown great potential in enhancing both the structural performance and microbial resistance of green cement. When nanomaterials, nCuO is incorporated into Portland slag cement (PSC), which already has a lower carbon footprint compared to traditional cement, enhances antibacterial and antialgal properties but adversely impacts the mechanical performance and to counter the adverse effect of nCuO, nSiO2 added to improve the mechanic performance. PSC is known for its ability to reduce industrial waste and CO₂ emissions, and the addition of nCuO and nSiO₂ makes it an even higher-performance material. Effects of nCuO and nSiO₂ on PSC have been studied by using isothermal calorimetry to assess hydration kinetics, X-ray diffraction to observe composition changes during hydration, scanning electron microscopy (SEM) to analyze microstructural changes, and mechanical testing to evaluate the strength of the material. The effectiveness of antimicrobial properties is studied in lab and field experiments. The results revealed improved compressive strength and significant resistance to bacterial and algal growth. The combination of nCuO's antimicrobial properties and nSiO₂'s ability to enhance the cement's strength created a synergistic effect that optimizes both performance and durability. Additionally, the study proposed a model to better understand the interaction between these nanomaterials, offering valuable insights into the mechanisms of hydration and microbial inhibition.

UV-driven self-replenishing liquid-infused surface with promising anti-algal adhesion performance.

Slippery liquid-infused porous surfaces (SLIPSs) inspired by Nepenthes have attracted much attention owing to their potential application in various cutting-edge fields. However, the performance of SLIPSs is impeded by surface damage and lubricant depletion, thereby limiting their further application. Herein, a UV-responsive slippery surface (SMEMG) was fabricated by introducing the UV-responsive functional group coumarin into the polymer side chain through random copolymerization, followed by crosslinking, curing and impregnation with vegetable oil. The self-healing ability and lubricant self-replenishing performance of the SMEMG were investigated. The results show that upon exposure to UV light, the damaged surface substrate can be repaired through a reversible photodimerization reaction between coumarin groups. Meanwhile, the lubricant oil within the bulk of the SMEMG substrate can be extruded to the surface during the photodimerization reaction, facilitating the recovery of surface wettability. The SMEMG exhibited excellent self-cleaning and anti-algal properties as well as durability in a harsh environment, demonstrating its promising application in marine anti-fouling.

Green synthesis of ZnO-chitosan nanoparticles and vinyl resin with effective antifouling properties

The demand for non-toxic antifouling protective paint or coating, intended to restrict the development of germs on surfaces exposed to water, has witnessed a remarkable surge in recent times. In this study, From Avicennia Marina, ZnO nanoparticles were isolated, while chitosan nanoparticles were obtained from shrimp shells. The synthesis of hybrid nanoparticles comprising ZnO and chitosan was successfully achieved through reflux conditions. Assessment of the morphology and various approaches were used to determine the size of ZnO-chitosan hybrid nanoparticles, including as Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), X-ray spectroscopy (EDS), Field Emission Scanning Electron Microscopes (FE-SEM) and Dynamic light scattering (DLS). ZnO-chitosan hybrid nanoparticles' effectiveness was evaluated using a range of laboratory biological experiments. ZnO-chitosan hybrid nanoparticles were tested for their efficacy against Escherichia coli (E. coli) at a dose of 50 μg/mL, while their impact on Staphylococcus aureus (S. aureus) was tested at a concentration of 25 μg/mL. Furthermore, Isochrysis galbana was significantly inhibited by these nanoparticles, with an inhibition rate of approximately 99 % after 48 h. The panel with the best and most effective outcomes contained 3 wt% ZnO-chitosan hybrid nanoparticles (The lowest measured weight of biofouling was 30.997 g). The results suggest that hybrid nanoparticles comprising ZnO and chitosan, along with vinyl resin incorporation, exhibit superior performance in terms of antifouling, antibacterial, and antialgal properties compared to both ZnO and chitosan nanoparticles.

The antibacterial and antialgal enhancement of the hydroquinone acrylamide polyurethane coating based on microphase separation

The undesirable and inevitable adhesion of marine organisms on submerged surfaces has seriously affect the environment, economy and society, so emerging and promising strategies for antifouling are required. Here, the novel and environmental strategy of the antibacterial and antialgal materials was proposed for the application of the antifouling coating without releasing harmful substances. The environment-friendly antifouling agent, the capsaicin derivative N-(2,5-dihydroxy-4-acrylamide meth-ylbenzyl)acrylamide (PHABA), was modified to the molecular chain of the polyurethane. The best tensile strength was up to 23.5 MPa of PUP-25% and the elongation at break was 415% of PUP-25%. The excellent wear resistance (300 wear cycles) and chemical solution resistance (H2SO4, NaOH, and NaCl solutions) revealed the applicability of the coating. PHABA would migrate to the surface of the polyurethane coating with time and enhanced the antibacterial and antialgal properties of the coating. PUP-25% prevented more than 90% of bacterial and algal adhesion, indicating the potential application of the antifouling coating.

Coral settlement induction by tetrabromopyrrole is widespread among Caribbean corals and compound specific

Tetrabromopyrrole (TBP) is a readily biosynthesized marine proteobacterial compound that induces coral settlement (attachment and metamorphosis) at concentrations ranging from 50 – 250 ng ml-1 (0.13 – 0.65 µM). This suggests a great potential for the use of this compound as a settlement inducer for restoration purposes. However, the applicability and optimal concentration of TBP for many coral species is not yet known. Furthermore, TBP is an unstable compound, which may present both challenges and benefits to its potential use for restoration purposes. In order to assess the utility of this compound for restoration, settlement induction by TBP was assessed among a wide range of Caribbean coral species. Additionally, a suite of halogenated compounds (tribromopyrrole, pentabromopseudolin, dibromophenol, tribromophenol, bromophene, n-methyl tetrabromopyrrole, tetrachloropyrrole, dibromoindole, n-methyl tetrachloropyrrole and dibromopyridine) that are related to TBP, some of which have similar antibiotic and antialgal properties, were also tested for settlement induction activity. These compounds were chosen based on their structural similarity to TBP or their identity as a product within the bacterial TBP biosynthetic pathway. TBP induced settlement in nine of ten coral species tested including seven not previously reported (Dendrogyra cylindrus, Orbicella faveolata, Colpophyllia natans, Diploria labyrinthiformis, Pseudodiploria clivosa, Acropora cervicornis, Montastraea cavernosa) at concentrations ranging from 0.375 – 1.5 µM. No other compound tested induced settlement, demonstrating a high degree of specificity for TBP.

Synthesis, Characterization, and Applications of Rare-Earth-Based Complexes with Antibacterial and Antialgal Properties.

The pursuit of environmentally friendly and highly effective antifouling materials for marine applications is of paramount importance. In this study, we successfully synthesized novel rare earth-based complexes by coordinating cerium (Ce III), samarium (Sm III), and europium (Eu III) with pyrithione (1-hydroxy-2-pyridinethione; PT). Extensive characterizations were performed, including single-crystal X-ray analysis, which revealed the intriguing binuclear structure of these complexes. This structural motif comprises two rare-earth ions intricately double-bridged by two oxygen atoms from the PT ligand, resulting in a distinctive and intriguing geometry. Furthermore, the central rare earth ion is surrounded by three sulfur atoms and two additional oxygen atoms, forming a unique distorted bicapped trigonal prismatic configuration. Compared with conventional antifouling biocides such as sodium pyrithione (NaPT), copper pyrithione (CuPT), and zinc pyrithione (ZnPT), these newly synthesized rare-earth complexes exhibited a remarkable boost in their in vitro antibacterial efficacy against both Gram-positive and Gram-negative bacteria. Additionally, these complexes demonstrated significant potential as antialgal agents, displaying impressive activity against marine planktonic organisms. These findings underscore the promising application prospects of these rare-earth complexes in the field of marine antifouling.

Seaweed-based alginate/hydroxyapatite composite for the effective removal of bacteria, cyanobacteria, algae, and crystal violet from water.

A novel cost-effective and multifunctional nanocomposite was developed based on sustainable macroalgae biomass. The brown seaweed Sargassum latifolium was utilized for alginate extraction and the calcareous red seaweed Tricleocarpa fragilis was utilized as CaCO3 source for nanohydroxyapatite synthesis. The developed Zn2+-crosslinked alginate/nanohydroxyapatite (ZA/nHA) beads were characterized by FT-IR, XRD, and TEM. The antimicrobial potential of ZA/nHA to disinfect synthetic Escherichia coli-contaminated water was evaluated at different bacterial load and composite concentrations. The developed ZA/nHA effectively inactivated bacteria at initial concentration ≤ 105 CFU mL-1 and 0.5-1% (w/v) of ZA/nHA within 300-360 min. The kinetics of bacterial disinfection exhibited better fitting to Weibull model than Log-liner model, which confirmed the disinfection process. Furthermore, treatment of the cyanobacterium (Chroococcus sp.) and the microalga (Chlorella sp.) with ZA/nHA showed promising antialgal properties as indicated by reductions in chlorophyll a. The treatment indicated 100% and 90% removal of Chroococcus sp. and Chlorella sp. within 2 and 4 days, respectively. The developed ZA/nHA also exhibited a promising application as a biosorbent for crystal violet (CV). The adsorption process was very fast (0.171 mg CV g-1 adsorbent was removed within 7 min at pH 6.0). The adsorption kinetics exhibited better fitting to the pseudo-second order and Elovich models than the pseudo-first order equation. Besides, Sips model better represented the isotherm data of CV adsorption. The thermodynamic analysis indicated exothermic adsorption, which became more favorable at low temperature and high CV concentration. The developed nanocomposite is eco-friendly and suitable for multiple environmental applications.

Mechanical performance and anti-fungal and anti-algal properties for teakwood/parawood/PVC composites in UV-weathering and seawater immersion conditions,

This work examined teakwood and parawood in wood/poly(vinyl chloride) composite (WPVC) materials under UV-weathering and seawater immersion. The mechanical properties as well as anti-fungal and anti-algal performance were considered. Teakwood and parawood (a rubberwood product) in WPVC materials at ratios of 0:100, 20:80, 40:60, 50:50, 60:40, 80:20, and 100:0 were investigated. UV-weathering ageing periods of 0 to 32 days and seawater immersion periods of 0 to 90 were studied. Aspergillus niger TISTR 3012 and Chlorella vulgaris TISTR 8580 were used as marine fungi and marine algae, respectively. Higher parawood content (in formulations of 0:100, 20:80 and 40:60) in WPVC composite materials enabled better mechanical properties than those of higher teakwood content (in formulations of 60:40, 80:20 and 100:0). Seawater immersion caused more deterioration of WPVC composite materials than UV-weathering ageing. Both anti-microbial agents and wood particles are potentially used in WPVC composite materials for anti-microbial properties, including the percentage reduction of fungal and algal growth. Increasing UV-weathering ageing and seawater immersion periods decreased the percentage reduction of fungal growth, but increased the percentage reduction of algal growth in WPVC composite materials. The results suggested higher parawood content (in a formulation of 20:80) for WPVC composite materials for coastal environment applications.

Dopamine-assisted sustainable antimicrobial peptide coating with antifouling and anticorrosion properties

Surface biofouling will seriously affect the performance of solid–liquid contact surfaces. Antimicrobial peptides (AMPs) are considered as potential agents for surface antifouling due to its broad-spectrum antimicrobial capacity. In this study, a derived AMP was synthesized by the reaction between a marine originated AMP and monomolecular dopamine, which was then used to modify 304 stainless steel. Mass spectrometry analysis confirmed the synthesis reaction of DP, and the co-culture essays with E11 and 293 T cells proved DP’s excellent compatibility. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis confirmed that DP was grafted on surface successfully, meanwhile, atomic force microscope, contact angle and 3D optical profilometer results demonstrated that surface morphology and wettability changed remarkably after modification. The results of Vibrio natriegens and Phaeodactylum tricornutum adhesion assays illustrated that DP treated surface possessed great antifouling capacity, and the antibacterial and anti-algal properties of the DP modified surface can reach 97.78% and 90.01%, respectively. Electrochemical results indicated that DP modified surface exhibited superior anticorrosion. The stability test results showed that DP modified surface possessed long-lasting properties in antifouling and anticorrosion. These findings may provide a useful tethering process for producing excellent antifouling surfaces in marine equipment, medical devices and other relevant fields.

Simulation Study of Poly-Caprolactone, Chitosan, and Vinyl Ester Resin-coated Stainless Steel to Improve Corrosion Behavior, Bioactivity, and Biodegradability

Heterogeneous materials are usually found in industrial and chemical centers, such as metallic alloy, polymer blending, porous and cracked materials, and especially composites. We exhibited expanded detailed studies on the integration of bonding between poly-caprolactone (PCL), chitosan and vinyl ester resin (VER), and stainless steel (SS) with h-BN substrates. Using h-BN dielectrics leads us towards a suitable improvement in mobility relative and increasing surface activities. Furthermore, we exhibited that the integration of h-BN with stainless steel (SS) exhibits unique advantages compared to exfoliated graphene. We offered higher resistance and anti-corrosion for stainless steel by forming these polymer layers on the surface sheet. Therefore, biopolymer strongly can be suggested as a perfect antifouling coating solution owing to its broad-spectrum antibacterial, antifungal, and anti-algal properties, along with amazing film-forming properties. Although atomic coordinates are adjusted by this work to reduce the molecular energy, conformational changes in the polymers might be considered to obtain the macromolecules pair correlation function. Gyration rays and end-to-end distance distributions of the chains have been applied to measure polymers' flexibilities quantitatively.

Rapid, continuous, large-scale synthesis of ZnO/Ag hybrid nanoparticles via one-step impinging stream route for efficient photocatalytic and anti-algal applications

Although there are many studies on ZnO/Ag nanoparticles, it is still a challenge to achieve rapid, economic, and large-scale preparation of ZnO/Ag nanoparticles with excellent photocatalytic and anti-algal properties, especially maintaining high Ag reduction rate in the industrial production process. In this paper, based on a self-designed impinging stream microreactor, ZnO/Ag hybrid nanoparticles were synthesized by one-step impinging stream route, and NaBH4 reductant with excellent reducing property for Ag was elected. The relative speed between the raw materials is very fast, the turbulent kinetic energy is large, and the shear force in the impact zone is strong, so the product nucleates quickly in a short time, and the ZnO/Ag nanoparticles have uniform particle size. Methyl orange (MO), methyl blue (MB) and rhodamine B (RhB) could be completely degraded over ZnO/Ag hybrid nanoparticles with Ag content of 2.5% in raw materials under UV irradiation for 15 min, 18 min and 12 min, respectively. Furthermore, the photocatalytic efficiency of MO reached 99.3% even after four cycles, demonstrating the excellent stability of ZnO/Ag hybrid nanoparticles. The growth of Skeletonema costatum was inhibited entirely when Ag content was 7.5% in raw materials. This work not only provides an effective strategy for rapid, continuous and economical producing ZnO/Ag nanoparticles, but also offers a valuable clue for large-scale production of the containing Ag nanomaterials with high reduction rate of Ag.

Antialgal Synergistic Polystyrene Blended with Polyethylene Glycol and Silver Sulfadiazine for Healthcare Applications

Polystyrene (PS) was blended with polyethylene glycol (PEG) and silver sulfadiazine (SS) with different weight proportions to form polymeric blends. These synthesized blends were preliminary characterized in terms of functional groups through the FTIR technique. All compositions were subjected to thermogravimetric analysis for studying thermal transition and were founded thermally stable even at 280°C. The zeta potential and average diameter of algal strains of Dictyosphaerium sp. (DHM1), Dictyosphaerium sp. (DHM2), and Pectinodesmus sp. (PHM3) were measured to be -32.7 mV, -33.0 mV, and -25.7 mV and 179.6 nm, 102.6 nm, and 70.4 nm, respectively. Upon incorporation of PEG and SS into PS blends, contact angles were decreased while hydrophilicity and surface energy were increased. However, increase of surface energy did not led to decrease of antialgal activities. This has indicated that biofilm adhesion is not a major antialgal factor in these blended materials. The synergetic effect of PEG and SS in PS blends has exhibited significant antialgal activity via the agar disk diffusion method. The PSPS10 composition with 10 w / w % PEG and 10 w / w % SS has exhibited highest inhibition zones 10.8 mm, 10.8 mm, and 11.3 mm against algal strains DHM1, DHM2, and DHM3, respectively. This thermally stable polystyrene blends with improved antialgal properties have potential for a wide range of applications including marine coatings.

Horseradish Essential Oil as a Promising Anti-Algal Product for Prevention of Phytoplankton Proliferation and Biofouling.

Increased proliferation of algae is a current problem in natural and artificial water bodies. Controlling nutrients is the most sustainable treatment of increased algal proliferation, however in certain cases, it is not sufficiently available, or it does not provide results fast enough. Chemicals derived from natural sources, which could be effective in low concentrations and are biodegradable, may have an advantage over conventional chemical treatments. The main aim of the present study was to investigate the anti-cyanobacterial and anti-algal properties of allyl-isothiocyanate-containing essential oil produced from horseradish roots with a complex approach of the topic: on laboratory strains of cyanobacteria and eukaryotic algae, on microcosms containing natural phytoplankton assemblages, and on semi-natural biofilms. The results show that acute treatment can significantly reduce the viability of all the tested cyanobacteria and eukaryotic algae. Results of microcosm experiments with natural phytoplankton assemblages show that horseradish essential oil from 7.1 × 10−6% (v/v) is applicable to push back phytoplankton proliferation even in natural assemblages. The individual number in the biofilm was dropped down to one-fifth of the original individual number, so 7.1 × 10−6% (v/v) and higher concentration of the essential oil can be considered as a successful treatment against biofouling.

Identification and antialgal properties of o-coumaric acid isolated from Eupatorium fortune Turcz

In our pervious study, the ethanol extracts from Eupatorium fortunei Turcz at concentrations of 200 ÷ 500 mg L-1 significantly inhibited the growth of Microcystis aeruginosa, which is the most common species, responsible for toxic cyanobacteria blooming in fresh water. o-Coumaric acid (or 2-hydroxy-cinnamic acid) isolated from E. fortunei was tested its growth-inhibitory effect on M. aeruginosa and Chlorella vulgaris at the concentrations of 1.0, 10.0 and 100.0 mg L-1 in the 96- hour experiment by the optical density and the analytical method of chlorophyll a concentration. Results indicated that the compound strongly affected towards M. aeruginosa at the concentration of 100.0 mg L-1 with the inhibition efficiency (IE) values of 76.76 % and 84.66 %, respectively while those for C. vulgaris were lower just of 60.59%, and 74.53 %, respectively. The obtained data demonstrated that two methods were highly consistent and o-coumaric acid was more toxic to M. aeruginosa than C. vulgaris at all tested concentrations (p<0.05). The images of M. aeruginosa and C. vulgaris cells under the light microscope clearly showed the damage of these cells under the attck of o-coumaric acid. Although o-coumaric compound was widely demonstrated antibacterial properties in previous reports, to the best of our knowledge, our study was the first report about effect of o-coumaric acid on the growth of M. aeruginosa and C. vulgaris.
 Những nghiên cứu trước đây đã chỉ ra rằng cao chiết etanol từ cây Mần tưới Eupatorium fortune Turcz tại dải nồng độ 200 ÷ 500 µg mL-1 ức chế mạnh sinh trưởng của Microcystis aeruginosa, - loài phổ biến nhất gây nên sự bùng nổ tảo độc trong hệ sinh thái nước ngọt. o-Coumaric axit (hay 2-hydroxy-cinnamic axit) phân lập từ E. fortune được tiến hành đánh giá ảnh hưởng lên sinh trưởng của hai loài M. aeruginosa và Chlorella vulgaris tại ba nồng độ là 1.0, 10.0 and 100.0 mg L-1 trong thời gian 96 giờ thực nghiệm theo phương pháp đo mật độ quang và phân tích hàm lượng chlorophyll a. Kết quả nghiên cứu cho thấy sau 96 giờ phơi nhiễm tại nồng độ 100 mg L-1 hoạt chất ức chế mạnh tới M. aeruginosa với giá trị ức chế sinh trưởng (IE) tương ứng là 76.76 và 84.66%. Giá trị IE đối với C. vulgaris ghi nhận thấp hơn chỉ là 60.65 và 74.53%, tương ứng. Hai phương pháp phân tích trên có tính nhất quán cao và o-coumaric ức chế sinh trưởng lên loài M. aeruginosa mạnh hơn so với loài C. vulgaris tại tất cả các nồng độ nghiên cứu (p<0.05). Ảnh chụp các tế bào M. aeruginosa và C. vulgaris dưới kính hiển vi điện tử đã chứng minh những tổn thương của tế bào dưới tác động của o-coumaric axit. Mặc dù o-coumaric cho thấy đặc tính chống khuẩn cao trong các công bố trước đây, nhưng theo hiểu biết của chúng tôi đây là nghiên cứu đầu tiên công bố về ảnh hưởng của hoạt chất o-coumaric axit lên sinh trưởng của M. aeruginosa và C. vulgaris.

A POTENTIAL ALGAECIDE FROM THE PRUNING WASTES OF GRAPE (VITIS VINIFERA) - STEMS AND LEAVES

A series of water quality and ecological problems are caused by algal blooms, and natural allelochemicals are considered as the source of algaecides due to their friendly advantages to environment. It has been reported that abundance of secondary metabolites are found in grape plants, and the extracts from the plant exhibit antioxidant, antibacterial and antifungal capacities. In order to reveal the anti-algal activity of grape pruning wastes and promote their usage, we analyzed the composition of the extracts from grape leaves and stems, and determined their effects on Chlamydomonas reinhardtii. The compounds identified from leaf and stem extracts included alcohols, aldehydes, ketones, acids, esters, phenolics, furans and terpenoids. Among these compounds, phenolics, furans and terpenoids were the main components. All of leaf and stem extracts can inhibit C. reinhardtii cell growth and reduce chlorophyll content and maximal efficiency of photosystem II photochemistry (Fv/Fm), and the inhibitory effects were enhanced with the increase of the extract concentration. The methanol extracts from grape leaves (MEL) contained the most compounds and had the strongest inhibitory effects. The response index (RI) of cell multiplication, chlorophyll a content, chlorophyll b content and Fv/Fm was -0.84, -0.83, -0.85 and -0.96, respectively, after the cells were treated with 12 mg.mL-1 MEL for 24 h. It has been reported that phenolics and terpenoids exhibit a wide range of antibacterial, antifungal and anti-algal properties, and they might be the main active ingredients to inhibit C. reinhardtii growth. Therefore, grape pruning wastes have a potential use value as an algaecide.

Chitosan-zinc oxide nanocomposite coatings for the prevention of marine biofouling

Marine biofouling is a worldwide problem affecting maritime industries. Global concerns about the high toxicity of antifouling paints have highlighted the need to develop less toxic antifouling coatings. Chitosan is a natural polymer with antimicrobial, antifungal and antialgal properties that is obtained from partial deacetylation of crustacean waste. In the present study, nanocomposite chitosan-zinc oxide (chitosan-ZnO) nanoparticle hybrid coatings were developed and their antifouling activity was tested. Chitosan-ZnO nanoparticle coatings showed anti-diatom activity against Navicula sp. and antibacterial activity against the marine bacterium Pseudoalteromonas nigrifaciens. Additional antifouling properties of the coatings were investigated in a mesocosm study using tanks containing natural sea water under controlled laboratory conditions. Each week for four weeks, biofilm was removed and analysed by flow cytometry to estimate total bacterial densities on the coated substrates. Chitosan-ZnO hybrid coatings led to better inhibition of bacterial growth in comparison to chitosan coatings alone, as determined by flow cytometry. This study demonstrates the antifouling potential of chitosan-ZnO nanocomposite hybrid coatings, which can be used for the prevention of biofouling.

Fabrication of silver nanoparticles from leaf extract of Butea monosperma (Flame of Forest) and their inhibitory effect on bloom-forming cyanobacteria

Silver nanoparticles (SNPs) are used extensively in areas such as medicine, catalysis, electronics, environmental science, and biotechnology. Therefore, facile synthesis of SNPs from an eco-friendly, inexpensive source is a prerequisite. In the present study, fabrication of SNPs from the leaf extract of Butea monosperma (Flame of Forest) has been performed. SNPs were synthesized from 1% leaf extract solution and characterized by ultraviolet-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM). The mechanism of SNP formation was studied by Fourier transform infrared (FTIR), and anti-algal properties of SNPs on selected toxic cyanobacteria were evaluated. TEM analysis indicated that size distribution of SNPs was under 5 to 30 nm. FTIR analysis indicated the role of amide I and II linkages present in protein in the reduction of silver ions. SNPs showed potent anti-algal properties on two cyanobacteria, namely, Anabaena spp. and Cylindrospermum spp. At a concentration of 800 μg/ml of SNPs, maximum anti-algal activity was observed in both cyanobacteria. This study clearly demonstrates that small-sized, stable SNPs can be synthesized from the leaf extract of B. monosperma. SNPs can be effectively employed for removal of toxic cyanobacteria.

Uses of 2-hydroxypropyl-3-piperazinyl-quinoline carboxylic acid methacrylate and Terbutryn as algaecides in low-density polyethylene mulching films for agricultural applications

The aim of this work concerned the performances and limitations of uses of two commercial biocides, namely 2-hydroxypropyl-3-piperazinyl-quinoline carboxylic acid methacrylate and N2- tert-butyl- N4-ethyl-6-methylthio-1,3,5-triazine-2,4-diamine (Terbutryn), in low-density polyethylene mulching film for agricultural application. The effects of type and algaecide concentration as well as aging deterioration of low-density polyethylene film surfaces were studied in relation to the mechanical, physical, and antialgal properties of the low-density polyethylene films. For antialgal evaluation, disk diffusion test and chlorophyll- a measurement technique were carried out on Chlorella vulgaris, a single-cell green algae, and Phormidium angustissimum, a blue-green algae. The results suggested that adding 2-hydroxypropyl-3-piperazinyl-quinoline carboxylic acid methacrylate or Terbutryn tended to slightly increase the lightness value (L*) of specimens, but did not affect the film mechanical properties. The disk diffusion test indicated that only Terbutryn at 600–1000 ppm resulted in clear zone development against C. vulgaris for low-density polyethylene film specimens. Regarding the quantitative study by chlorophyll- a measurement technique, the antialgal activities of low-density polyethylene films gradually improved with increasing algaecide concentrations. Terbutryn appeared to show more effective antialgal efficacy than 2-hydroxypropyl-3-piperazinyl-quinoline carboxylic acid methacrylate. Under aging deterioration, Terbutryn-low-density polyethylene films showed less degradation of mechanical properties than neat low-density polyethylene films. However, the antialgal activity of Terbutryn-low-density polyethylene films at various algaecide concentrations was reduced under both accelerated UV weathering and natural outdoor exposure.

Phytochemical investigation and antimicrobial activity of Derris scandens

Different fractions of root and stem of Derris scandens demonstrated good antibacterial (Escherichia coli, and Bacillus megaterium), antialgal (Chlorella fusca), and antifungal (Microbotryum violaceum) activities. Phytochemical investigation resulted in isolation of scandenin, scandenin A, betulinic acid, lupeol, β-amyran-3-one, β-amyrin, β-sitosterol and ß-sitosterol glucopyranoside. Study showed that scandenin has strong antibacterial activity against B. megaterium and good antifungal and antialgal properties. Scandenin A showed good antibacterial, antifungal and antialgal properties.

Cyanobacteria: Photoautotrophic Microbial Factories for the Sustainable Synthesis of Industrial Products.

Cyanobacteria are widely distributed Gram-negative bacteria with a long evolutionary history and the only prokaryotes that perform plant-like oxygenic photosynthesis. Cyanobacteria possess several advantages as hosts for biotechnological applications, including simple growth requirements, ease of genetic manipulation, and attractive platforms for carbon neutral production process. The use of photosynthetic cyanobacteria to directly convert carbon dioxide to biofuels is an emerging area of interest. Equipped with the ability to degrade environmental pollutants and remove heavy metals, cyanobacteria are promising tools for bioremediation and wastewater treatment. Cyanobacteria are characterized by the ability to produce a spectrum of bioactive compounds with antibacterial, antifungal, antiviral, and antialgal properties that are of pharmaceutical and agricultural significance. Several strains of cyanobacteria are also sources of high-value chemicals, for example, pigments, vitamins, and enzymes. Recent advances in biotechnological approaches have facilitated researches directed towards maximizing the production of desired products in cyanobacteria and realizing the potential of these bacteria for various industrial applications. In this review, the potential of cyanobacteria as sources of energy, bioactive compounds, high-value chemicals, and tools for aquatic bioremediation and recent progress in engineering cyanobacteria for these bioindustrial applications are discussed.